Podcasts about monoids

The First Doctor and the Earth's destruction! Dom Bettinelli and Jimmy Akin discuss this story of the Doctor encountering the last humans and a race of Monoids in a tale of disease, suspicion, conflict, and betrayal, highlighting the time-jumping narrative, Dodo's introduction, and more.

The First Doctor and the Earth's destruction! Dom Bettinelli and Jimmy Akin discuss this story of the Doctor encountering the last humans and a race of Monoids in a tale of disease, suspicion, conflict, and betrayal, highlighting the time-jumping narrative, Dodo's introduction, and more. The post The Ark appeared first on StarQuest Media.

Join Rod, Joe, Tim & Frazer as we enter a turbulent period of the shows early history but a fruitful creative patch. We face Rills, Daleks, Greeks, more Daleks, Catholics and Monoids on our quest to crown this half season.

Friends, what if we told you that we have the perfect Halloween costume idea for you and you'd get to go the whole night without having to talk to anyone! No? You don't want to have a ping pong ball in your mouth all night? Alright then, fine! But just hear us out as we talk about the Monoids, the plague that Dodo brings, the 1st Doctor "hmm'-ing a lot, Cushman carts of the deep future, and an honest-to-goodness elephant on set as we review the First Doctor adventure The Ark!!

Friends, what if we told you that we have the perfect Halloween costume idea for you and you'd get to go the whole night without having to talk to anyone! No? You don't want to have a ping pong ball in your mouth all night? Alright then, fine! But just hear us out as we talk about the Monoids, the plague that Dodo brings, the 1st Doctor "hmm'-ing a lot, Cushman carts of the deep future, and an honest-to-goodness elephant on set as we review the First Doctor adventure The Ark!!

The episode where we contemplate the worst consequences of us failing at our jobs, and the ramifications for the human race. Do the Monoids call the humans Duoids? On this podcast, we've been taking a look at our instruments in there, and it's really very strange! This episode was recorded on 21 October 2023. Email us at thedoctorswatcher@gmail.com. Follow us on Tumblr at the-doctors-watcher. I guess we also have a Twitter or whatever. Check out Circuit 23's music at http://soundcloud.com/circuit23 and email him at circuit.23@gmail.com. Listen to his album “Mens Vermis” at https://circuit23.bandcamp.com/album/mens-vermis.

Forget the Star Beast, the return of David Tennant and that surprise cameo by the Monoids.... probably. It's time for a brand new episode of Too Hot For TV. This time Dylan is joined by Pete Lambert, together they traverse both comics and audios. First up it's the Doctor Who Weekly comic strip 'The Tide of Time'  written by Steve Parkhouse with art by Dave Gibbons, featuring the Fifth Doctor. Then it's Sixth Doctor and Charlie Big Finish Audio 'The Condemned' written by Eddie Robson and directed by Nick Briggs.  And as always they answer the questions: Who is Peter Davidson?Who had a catalogue of imaginary Doctor Who Toys?Which doctor who monster is not a Twink? 

If you're in the market for bicycle shorts, Joël's got you. Stephanie just returned from RubyKaigi in Japan and shares details of her trip. Recently at thoughtbot, there have been conversations around an interesting data modeling exercise. Joël and Stephanie discuss the following: Value Objects vs. Hashes Doing Math on Compound Numbers Monoids and Folding Naming Concepts in Code This episode is brought to you by Airbrake (https://airbrake.io/?utm_campaign=Q3_2022%3A%20Bike%20Shed%20Podcast%20Ad&utm_source=Bike%20Shed&utm_medium=website). Visit Frictionless error monitoring and performance insight for your app stack. Ruby Kaigi (https://rubykaigi.org/2023/) Google Translate Lens (https://lens.google/) Video on city parks (https://www.youtube.com/watch?v=qnyikrFlGdU) Enumerable#tally (https://ruby-doc.org/3.2.2/Enumerable.html#method-i-tally) Hash#merge (https://ruby-doc.org/3.2.2/Hash.html#method-i-merge) Monoids (https://blog.ploeh.dk/2017/10/06/monoids/) Enumerable#all? (https://ruby-doc.org/3.2.2/Enumerable.html#method-i-all-3F) Value of specialized vocabulary (https://www.bikeshed.fm/356) Gist with Joël's code solution (https://gist.github.com/JoelQ/3056a0a6e8b5488faa5caeef630cd702) Transcript: STEPHANIE: Hello and welcome to another episode of The Bike Shed, a weekly podcast from your friends at thoughtbot about developing great software. I'm Stephanie Minn. JOËL: And I'm Joël Quenneville. And together, we're here to share a little bit of what we've learned along the way. STEPHANIE: So, Joël, what's new in your world? JOËL: I've made an unusual purchase this week. I went out and bought a pair of bicycle shorts. And, for those who are not aware, these are special shorts that have padding built into them. Typically, they're, like, skin-tight, but I got, I guess, what are called mountain biking shorts. So, they kind of look more like the cut of a normal short. But they've got this, like, built-in padding for biking. STEPHANIE: So. Just to confirm, you did get these shorts for biking purposes, right? JOËL: Yes. I purchased these shorts for biking purposes. STEPHANIE: Okay. [laughs] JOËL: And I got these because I was talking to a friend about this and mentioning that this was, like, probably the most ambitious cycling thing I've ever done in my life. And they recommended if you have not done bike shorts, you really should get them. They make a big difference. STEPHANIE: Wow. Okay, I have two thoughts here. First of all, you prefaced this saying that this was an unusual purchase. So I thought maybe that you bought these bike shorts for some other purpose. [laughs] But I am excited to talk about this because I've also been curious about trying bike shorts. I bike a lot in Chicago in the summer, and I've been doing, like, longer rides on the Lakefront trail. And one of my goals, actually, this summer is to do a bikepacking trip. But I have not been super comfortable on longer rides. And I was just thinking that this might be something really helpful to make them a little more enjoyable. JOËL: So, is the kind of biking that you're doing closer to what might be considered commuting? STEPHANIE: Yeah, mostly commuting. But also, just, like, going on long rides on the weekends, in addition to this, hopefully, forthcoming bikepacking trip up to a state park. So not too long, maybe, like, 60 miles, but definitely long enough to start getting a little uncomfy on your seat. JOËL: Yeah, is 60 miles, like, in one day? STEPHANIE: Yeah, exactly. JOËL: That's a lot. Yeah, the friend who recommended biking shorts to me told me that pretty much anything over maybe 10 miles is worth getting shorts. STEPHANIE: Wow, okay. I clearly have been suffering [laughs] for way too long, then. Tell me more about your cycling trip. JOËL: So this is a bikes plus beer trip. Basically, I plotted a bunch of breweries in Belgium on a map and constructed an itinerary that could hit a bunch of them while keeping fairly short rides between towns. And the goal is to do maybe 30-35 miles in a day. And so I'll be going probably, like, cycling in the morning, and then exploring and drinking in the afternoon and evening. STEPHANIE: That sounds amazing. That's really cool to do a little bit of a tour of the area and then also traveling by bike. JOËL: Yeah, I'm excited because other modes of transport really just give you the origin and the destination, whereas cycling, you kind of get all of the in-between places. You get a much better feel for the area that you're in. And you can make all these unexpected stops if you want. You can make detours. So I feel like you get the sort of being in the moment, being in the place effect that you would have as a pedestrian but with a much longer reign. STEPHANIE: Yeah, absolutely. That's exactly what I was going to say. I love cycling. And there's something really special about being able to be present in your surroundings and seeing people on the street or a cool building as you're going. But also going at a speed where it feels very fun and very freeing to just be cycling through a town and making stops when you want to, and traveling greater distances than you could be able to on foot. JOËL: So I just received these bike shorts yesterday in the mail. So today, at the end of the day, I'm going out for a bike ride, and I'm going to see if they perform as advertised. STEPHANIE: That's exciting. Keep us posted [laughs] on if you end up liking them or not. JOËL: Yeah, yeah. The next episode or two, I'll have to report bike shorts; yay or nay? STEPHANIE: Yeah, The Bike Shed will now become bike gear reviews. JOËL: The name will actually line up, then with what the people googling, it might think it actually is. Stephanie, what's new in your world? STEPHANIE: Speaking of vacation, I just got back from a two-and-a-half-week trip myself. I mentioned on the podcast a couple of episodes ago, I think, that I was traveling to Japan for RubyKaigi, an international Ruby Conference over in Japan. And then I spent another week in Taiwan, just on my own time. So, yeah, I had a really big, long trip, and it was really great. It was my first time going abroad in a really long time. It was my first time being somewhere where I didn't speak the language. So, in Japan...I don't speak any Japanese. And it was both challenging and also, like, not too bad. I found my way around through a lot of gesturing and smiling, and nodding. [laughs] And, hopefully, people were able to understand what I was trying to communicate. Also, pointing at menus, I highly recommend going to places that have pictures of the food, and then you can just point when you want to order. [laughs] JOËL: So, did you find that English was not particularly useful then in Japan as a tourist? STEPHANIE: Yeah, I would say so. The next thing was that most signs were translated. So we ended up taking public transportation a lot. And that was quite easy to navigate, especially since I have kind of navigated subways in other cities before, and reading the signs is no problem. But when you're trying to communicate with locals, that was a little harder. JOËL: Did you use any, like, apps on your phone or anything like that to help navigate kind of the different language? STEPHANIE: Yeah, the Google Translate Lens app. I can't remember exactly what it is. But this was my first time really using it. And I was really impressed by how it was able to translate things that you're using your camera to take pictures of, or just, like, having your camera view. I did feel a little silly, like, holding my phone up to everything and trying [laughs]...so I could understand what I was reading. But for menus that did not have pictures, that was my backup strategy. [laughs] JOËL: Did you ever have to have your phone translate something and then just show your phone to someone else? STEPHANIE: No, I didn't have to go that far. Though I do think that it has a feature where you can have someone speak into the phone, and it will translate that into your native language. And then you respond by speaking into it and then playing the sound for them, which, you know, I bet really works in a pinch. But I think that required a little more investment into the interaction [laughs] with the other person than I was ready for. Like I said, the gesturing served me quite well. JOËL: I got the experience of being on the other side of that a while back. So, here in Boston, I was just walking down the street, and someone stopped me and just holds up their phone. And they've typed something in Chinese on there. And they hit a button, and it comes in English. STEPHANIE: [laughs] JOËL: And they're asking for directions. And I think I typed a sentence back on their phone in English, and then they hit the translate button and got it back in Chinese. We went back and forth a few times. And eventually, I think he got what he wanted, and we went our separate ways. And I was kind of amazed that this whole interaction happened. STEPHANIE: Yeah, that's really cool. JOËL: Yeah, kudos to that person for having the courage to stop someone on the street when you don't speak their language. STEPHANIE: Yeah, absolutely. I think even when I was struggling to communicate with someone because of the language barrier, I could tell from their gesturing in return that we were, like, willing to help each other out. And that, like, there was still an ability to find some kind of connection, even though, you know, we didn't completely understand each other. And that was definitely one thing that I really enjoyed was being in a place with, you know, people different from me and having that exposure. It's been a really long time since I've got to experience that, and that was really valuable. JOËL: So, other than the conference, what would you say are some highlights of the trip for you, maybe one from Japan and one from Taiwan? STEPHANIE: So one of my favorite things about being in Tokyo was all the green space that was around. I ended up walking a lot just to explore the neighborhoods. And I always just stumbled across a local park or even a shrine that had really great nature around it, a lot of big trees. You know, some, like, water features, maybe like a pond, and a lot of really fun plants that I got to learn about. And, yeah, that was really nice, especially in such a dense urban area, like, coming across green space to just sit for a little while. And it was such a nice relief from the density and busyness of a big city. That was just one thing that I was really impressed by being in Japan. JOËL: That's really cool. I think that really speaks to the quality of their urban planning. I know that the stereotype of Tokyo that I have in my mind is that it's, like, you know, ultra-modern, ultra-urban, you know, it's the largest city in the world. So the idea that they've taken the time to set up all these little parks everywhere is really endearing. Particularly, I think the idea of smaller parks at the neighborhood level where you don't need, you know, something massive like, let's say, New York's Central Park, which is, you know, really cool. But having just a little green space in your neighborhood where you can, like, stop by, I think it's a wonderful upgrade to local people's quality of life. I was recently listening to a video on YouTube from a city planning channel talking about just all the thinking that goes behind city parks, and having them at different scales, and how that impacts the residents of different areas. So it's really cool to hear that Tokyo has done a great job with that. STEPHANIE: Yeah, absolutely. I think part of the joy of just stumbling upon it was that you know, even when I wasn't seeking it out, it would just come along during my walks. And, yeah, it really was very refreshing. JOËL: What about Taiwan? STEPHANIE: So, in Taiwan, what I really enjoyed about it it's a bit of a smaller island. And so you can actually get to a lot of places within a few days. And a lot of folks take day trips out to the coast from Taipei. And I was able to do a two-day trip to another county that had some hot springs, and I got to enjoy an outdoor hot springs in the rain. And that was really nice because it was, like, surrounded by trees. And it happened to be raining that morning, but, you know, we were all kind of already getting wet, so it didn't really matter. And it was just, like, this really serene and gorgeous experience being able to enjoy that. And I think that was another place where I was in a very urban area, and then being able to escape a little bit was really nice. JOËL: That sounds like a magical moment. Have you visited hot springs before, or was this your first time going to a hot spring? STEPHANIE: I have been to a few in the U.S. before. I like to take road trips to national parks. And there are some really great hot springs in the U.S. as well. And so this was kind of something that I really wanted to do somewhere else just to experience it elsewhere. And, yeah, I'm really glad to have checked that off my bucket list. JOËL: That's really cool. I've never been to a hot spring, and it sounds like a fun thing to do. So it's on my kind of greater bucket list. It's maybe not a top-five thing to do, but definitely, something I want to do one day. STEPHANIE: Cool. Love it. That was vacation talk from Joël and Stephanie. [laughs] MID-ROLL AD: Debugging errors can be a developer's worst nightmare...but it doesn't have to be. Airbrake is an award-winning error monitoring, performance, and deployment tracking tool created by developers for developers that can actually help cut your debugging time in half. So why do developers love Airbrake? It has all of the information that web developers need to monitor their application - including error management, performance insights, and deploy tracking! Airbrake's debugging tool catches all of your project errors, intelligently groups them, and points you to the issue in the code so you can quickly fix the bug before customers are impacted. 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JOËL: So recently at thoughtbot, we've been having conversations around this really interesting data modeling exercise, where let's say this is a company, and you want to purchase T-shirts for everyone at the company. You have already some T-shirts on hand because you've done this kind of thing before in a couple of different warehouses. And you need to know how many new T-shirts you need to order in order to have enough for everyone. So as long as you keep things simple, the math is pretty easy because you sum the number of people at your company, and then you sum the number of shirts across all of your warehouses, and that gives you the T-shirts that you need, the T-shirts that you have. You get the difference between those two numbers, and that tells you how many new T-shirts you need to order. Where things get more complicated is once you start introducing T-shirt sizes, and that's where the fun data modeling comes in. If everyone at your company has a T-shirt size that they want and then at your warehouses, you store...the object that represents a warehouse stores a hash of sizes and how many of each size you have. Now, how do you do all this, like, summing across things? And it's not really just a single number that you want. Now you need to know how many small, mediums, and larges. And, sometimes, you've got a hash. Sometimes you've got just symbols on a user, and you've got a sum across hashes. Maybe do some differences across hashes. And it gets kind of tricky to work with. So that's sort of the problem as it's initially presented. And we've been having a really interesting conversation around different ways to try to solve it in a way that's really kind of clean and nice. STEPHANIE: Yeah, that's interesting because what you described sounds like the first iteration of solving the problem is, oh, the warehouse stores this information as a hash. So maybe I will create a new hash for the counts of T-shirt sizes that I need and then do the comparison on those two hashes. It sounds like maybe there was some unwieldiness or maybe even some duplicated code there. Is that what you think you all were trying to solve by modeling this differently? JOËL: I think we kind of quickly hit some limitations with hashes. One thing that is fun before we start trying to combine a bunch of hashes is that some of the data exists as a hash on the warehouses. But to get the T-shirts that we need, all we have are an array of users and a size on all of them. And we can use this fun method from Enumerable called Tally to give us a kind of Tally hash that is just a mapping of size, two counts of that size in the array. And so that's a really fun method. You don't get to bring it out that often in Ruby. And it's nice because that hash format happens to match the same format as the hashes stored on the warehouse objects. STEPHANIE: Right. So now you're comparing apples to apples. But it sounds like maybe this hash representation does hold some kind of significance. JOËL: Yeah. I guess, for me, I tend to see anytime you're doing fancier operations on a hash more than just reading in and out; it probably wants to be some kind of value object. And, in this case, we kind of want to do math on hashes. I think the equation is kind of still the same thing. We're trying to get the difference between the two, between the want versus have, but you can't just subtract one hash from another directly. There's some things that you can do with the hash merge method that allows you to pass a custom block and do some things there. But we're going to have to do this sort of repeatedly. And now we're kind of leaking some of that knowledge a little bit. So it feels like something where you might want to actually name this concept and make it an object of its own that can then have its own kinds of domain operations as methods on it. STEPHANIE: Yeah, I like that a lot. Because even just as I was thinking about it when you are storing data like that in just a hash, what do you call it? Like, what do you name it? I think I've seen things like that named, like, T-shirt data, or, like, warehouse data, or warehouse T-shirt counts, or T-shirt counts. You know, that is when it starts to diverge, and you end up maybe seeing the same, like, data represented, but it being named different things in different parts of the code. And I, in experience, have found that very painful. JOËL: Yeah, because I guess you could have, like, T-shirts on hand from your warehouse; that's one hash. But the hash generated from the users might get called something like user preferences. And if you're reading through that code and you see a hash, and you're like, okay, do these two hashes that I'm looking at, maybe in a test, just kind of coincidentally have the same keys? Or are these kind of fundamentally the same thing? Or is the idea of, like, T-shirts on hand like a stock different from, like, a preference? And do they represent different things that just happen to be similar in this particular scenario? STEPHANIE: Right. And especially if then there are methods where you're passing that data structure that really represents the same thing. But you're passing it as arguments, and then, suddenly, one variable name, user preferences, or user T-shirt preferences becomes, you know, T-shirt count. That has been really confusing for me before. JOËL: One thing that does get, I think, clunky very quickly is that you have all of these warehouse objects that have that hash of, like, stock on hand on them. And what you really want is a kind of aggregate object that tells you not what's the stock on hand for one warehouse but across all warehouses. So you've got to go through, I guess, that array of warehouses and somehow kind of aggregate all of those hashes together. And because they're already tallies, you can't just do Enumerable Tally on it anymore. You've got to find some way to combine them together, and that gets tricky really quickly. STEPHANIE: Right. I can see they're starting to be, like, nested loops, especially if you're just working with primitives. JOËL: I think some initial implementations that we saw ended up doing either, like, some kind of reduce block or eachwithobject, or something like that, which are, I think, fine solutions here. But what lives inside of those blocks is what gets complicated. And I don't know about you, but I feel like if I'm reading through some code and then all of a sudden I see a reduce block, and it's, like, ten lines of logic with maybe some, like, nested things, like, maybe some nested loops or some conditions inside of it, that's kind of intimidating. Reduce is not a super easy method to wrap your head around, especially when the block has got a lot of logic. STEPHANIE: Yeah, that's a really good point. It definitely gives me pause. And I have to, like, you know, commit to reading the method in its entirety to fully understand [laughs] what's going on. JOËL: Sometimes, like, really pause and, like, annotate with comments and all this stuff. STEPHANIE: So, what did you end up thinking about in terms of solving that problem of aggregating the sums of all the different T-shirt sizes for each warehouse? JOËL: So I think, for me, oftentimes, it's easier to make the problem a little bit smaller, solve that smaller problem, and then try to kind of scale up back up again and particularly when you're dealing with something like reducing or aggregating a large collection. Like, forget about dealing with a collection. Just how could I combine two items of this type? So if I had two of these hashes. And forget about fitting it for an array. But if I have two of these hashes, how could I combine them together? And you could do this with hash merge. I wanted to do things a little bit more encapsulated. And because I also knew that we're building some more logic around these, I actually wrote a custom object. I called it a tally, maybe inspired by that Enumerable method, and implemented an operator plus on this tally object. So a tally object can plus another tally object. And the response from that is you get a third tally object that's gone through all of the keys and summed them together. So it's kind of an aggregate sum. STEPHANIE: This is a cool example of a method that's a verb also representing a noun to name the return value, right? So the Tally method on Enumerable returns a hash, which we have been talking about for a while as, like, a data structure that's, you know, perfectly fine, but maybe we can leverage turning it into like you said, a value object to give it more meaning or to make it easier to work with. And it seems like the naming part just kind of fell into your lap. JOËL: Yeah, tally is interesting in that it is both a noun and a verb in English. I'm not sure what the grammatical term for that kind of word is. STEPHANIE: So, once you extracted this new class out, what insights or observations did you have about this problem? JOËL: What becomes really cool about this is that once you have a way of combining two objects together, reduce is a way to just kind of scale that up to an arbitrary number. And so, just like you can sum an array of numbers by reducing plus over the array. Because I have plus on my tally object, I can reduce plus operator over an array of tally objects. And they all just kind of sum together in a single tally that's the combination of all of them. So this is really cool. What used to be an intimidating reduce block, the intimidating logic gets moved into a plus method, which I think is much more approachable. Because I can go in the context of an object and say, okay, I've got this tally object, and I'm trying to add it to another tally object. And we're just going one key at a time, adding them together. Simple enough. And then in the place where we're reducing, all we're saying is list of tallies reduce plus. And I know that pattern already because I do it with integers to sum them together. And so now I've just got this really simple one-line in the scary part. And the actual complex logic is much more approachable. STEPHANIE: That is very cool. I found it really interesting that this came about because we were trying to do math on these two hashes. So it seems like, you know, a tally because it represents a score or, like, a number. Like, we were able to implement those plus operators and get to a simple solution because we're working with numbers. JOËL: Yeah, I think it might be fair to describe it as maybe a compound number is the term that I use. I don't know if that's mathematically correct. Oftentimes, when you're dealing with things that represent a number or something that's represented numerically but that might have more than one number involved in it. But you still want to do math with this kind of compound, multi-number value anyway. And one example that you might have is, let's say, a point in 2D space. You have an X coordinate and a Y coordinate. And you can do math on points. In fact, there's a whole field of math to deal with that kind of thing. That's an important thing that you have to do. You might want to be able to add or subtract points. You might want to do certain types of multiplication on them. And so just because something has more than one number associated to it doesn't mean that it can't be used for math. In fact, oftentimes, that's where the fancier math does come into play. But when we treat them as primitives, and we just have, let's say, our XY pair was a hash, or, like, a two-element array, then we lose the ability to do math nicely. If we create, let's say, a point class that has an X and Y, and then we define plus, we define minus, we define scalar and vector multiplication, things like that, now we can do all those operations. And we can treat it like math, even though it's not just a simple integer anymore. STEPHANIE: Yeah, I like that a lot because we do end up working with data, you know, maybe even from our database. But then, inevitably, we want to, like, learn something about it. And so I was thinking about how frequently I use GROUP BY in MySQL queries and how, oftentimes, I care about counts, or, like, number of records. And perhaps this is why we see, like, the hash primitive used so frequently in codebases that then become pretty complicated once we're trying to, like I mentioned, like, learn something about it or, like, compare things or whatever logic that we need to do. And transforming them into objects that then know how to do math on themselves [laughs] is very cool. JOËL: Hashes are interesting because they're pretty much just basic data structures. And I think, very often, they're sort of pre-objects. They're things that want to eventually become objects. And, oftentimes, what I find is that hashes get passed around a system. And various other classes or subsystems all have bits of logic that act on the hash because the hash can't own that. And so you end up with the logic around the concept of whatever the hash represents kind of scattered and maybe duplicated across three or four places in the application. And then, all of a sudden, if you give that a name, if you create a class for it, you can pull all of that logic into one place. And, all of a sudden, it probably cleans up all of the surrounding places because now they don't have to care about the implementation of exactly what operating on the hash is. But, also, it means that these operations generally have, like, nice domain names. And, in the case of a complex number, you might even have that represented through math operations, like, plus or minus. And that allows your code to read really nicely. STEPHANIE: Right. Which gets me thinking about how I mentioned, like, tally as a noun, and, you know, you implemented your custom class. But do you think there's any value in the idea of a tally being specifically like a hash-like thing with a number as the value for each key, like, that existing as a more general class for people to use? JOËL: Oh, that's interesting. So, in my personal implementation, I hard-coded values for small, medium, and large because those were the T-shirt sizes from the example. But you're talking about some sort of generic tally object that maybe would be a gem or something like that that people could use that represents counts of arbitrary things or multiple counts of arbitrary things that might then implement some common math operators so that you could add or subtract them. STEPHANIE: Yeah, exactly. Because I was just thinking, you know, like I mentioned, I often represent that when I count number of records in my database. Or even I can recall a problem that I encountered previously where I had to figure out the number of orders for an e-commerce store based on the location. And I held that in a hash data structure, but really, it's a tally. [laughs] And so, yeah, I think that maybe we've kind of stumbled across a very useful representation of very common problems. JOËL: Yeah, I can see there being use for a generic version of this. Maybe that's your chance to go out and create some open source, or maybe this already exists. We should maybe research that first. STEPHANIE: Yeah, if any one of our listeners know, [laughs] send us an email. JOËL: So something that was really interesting to me about all of these changes, introducing the value object, cleaning up the reduce, all that stuff, is that, in the end, once the...there was this object that represented the sort of aggregate compound value, the tally, then the equation stayed the same. And I can just slot in those variables as before. Whereas previously, when we switch from just a single count to this, like, we need to take into account sizes that, like, broke the initial implementation of the code. So it's funny how you sort of go from a simple implementation and then a new requirement, which breaks it. But then just changing the hash to be an object all of a sudden made the original code, which didn't really need to change; it just worked again. STEPHANIE: Hmm. That's really interesting because it makes me think about how maybe the primitives were perfectly fine, you know, in the first set of requirements, and not until, like, an additional complexity or something new emerged that we needed to reach for an object that could support the change. JOËL: Yeah. And I think I'd argue that if you're doing just raw T-shirt count, an integer is probably the right value to use there. But if you're doing counts broken out by T-shirt size, then having an object that's a single thing that responds to plus and minus so that you can use it in the same equation where you're saying sum up all of these things from the warehouse, and then do a difference with the T-shirts that we need that becomes really nice. STEPHANIE: Do you think there was some value in going through the hash implementation first, though, and then arriving at using a more custom object? I'm curious, kind of, like, what that journey was like. JOËL: It's hard to say. I would say maybe yes. But I could also see someone who's done this a lot, who's built the sort of heuristics, the instincts around this could immediately be like, oh, wait, we're trying to sum hashes here. Clearly, these need to be objects. Clearly, what we need is something that implements a plus operator that we can reduce. STEPHANIE: Yeah, I like that a lot. Because part of, you know, knowing what to reach for is having seen it enough times and seeing patterns, right? JOËL: This reminds me of a particular pattern that comes from the world of functional programming. It has a kind of scary-sounding name. It's monoid, not monad, monoid. And the idea in the context of Ruby is it's some kind of object that implements a plus method. So two of these objects can combine each other. And typically, you also have some sort of empty version of this object or some sort of, like, zero value. And there's a few rules that go around, like, kind of how this object has to behave. Like, you can't just put any implementation you want in that plus method. Certain requirements that have to be met for it to be considered, like, a valid plus method in this pattern. But if you do meet those requirements, then arrays of this type of object are just inherently reducible because you can just reduce plus over them. And so I think anytime you're trying to aggregate some sort of unwieldy data structure, that's probably a useful pattern to have because, you know, wait, as long as I have a way to combine two items together and potentially some way to generate an empty state, I can aggregate this whole list. STEPHANIE: I'm curious, does that also apply to non-numerical values? JOËL: Yes, any kind of aggregation combination, whatever. So maybe what you're doing is you're combining strings together. STEPHANIE: Got it. JOËL: String concatenation is a form of combination. And so you could be reducing some kind of concatenation over an array of strings, and you end up with one aggregate string that's the combination of all of them. Sometimes, though, you're not just taking values and putting them next to each other so that what you have is kind of all of them at the same time. You might instead do some kind of comparison. An example here might be Boolean values. You might say the way that I'm sort of, quote, unquote, "aggregating" two values, two Boolean values is with the operator AND. And so you have two Boolean values, and you get a new sort of combo value out of them, that is, are both of these values true? STEPHANIE: Whoa, that's blowing my mind right now. Because I had never thought of the, like, AND operator on Booleans, essentially aggregating them into a single true or false value. [laughs] JOËL: It's kind of weird, right? But I guess we do the same thing with numbers. One plus one doesn't give us 11 unless you're writing JavaScript. STEPHANIE: [laughs] JOËL: You know, we get a new number too, that is some sort of, like, combination of the two. So, similarly, it kind of makes sense that two Booleans might combine to create a new sort of third Boolean value. Where it gets really interesting, though, is that once you have this sort of combination, if you try to reduce AND over an array of Booleans, what you effectively have created is Ruby's Enumerable all method that checks to say, are all values in this array true? STEPHANIE: Interesting. But really, the way that's implemented is just, like, a definition of what aggregate means for Booleans, right? JOËL: Right. But it's taking that idea of aggregating two values and scaling it up to an array of many values. So we know Boolean AND. Another way to think about it is, are both of these values true? Is the question it's trying to answer. And then we're scaling that out to say, is both of these values true for everything? So are all of these values true? Because we're going from two to many. STEPHANIE: Cool. So maybe the takeaway for some of our listeners could be, like, next time they find themselves having to deal with a collection or an Enumerable and, you know, using a reduce or, like, trying to break it down to compare two of those elements first, and figuring out how they want that interaction to work. Does that sound right? JOËL: Yeah, absolutely. Once you have a way to combine two elements together, if you want to scale it up to n elements, you just plug it into reduce, and it does the rest of the work for you. My big takeaways from this exercise were one: the value of creating custom objects. Wrapping primitives like hashes in an object and adding a few domain methods on them made such a difference in my final implementation. Secondly, I think it's what you're saying, this whole thing about breaking down complex reduce problems by figuring out how to combine two items and then just using reduce to scale it to an array. And then, finally, I think this is a point that we've mentioned on this podcast before, the value of specific vocabulary - being able to name things and patterns. And so knowing some of the details of this monoid pattern and having a name for it means that now I start seeing it in places. And so the moment I see, oh, wait, we're aggregating values; we're combining two values together and then doing this in a reduce, immediately, my mind goes, wait, that feels like monoid. And then, I can explore that with my custom object to try to make the code better. STEPHANIE: Yeah. And even if you don't remember the monoid part specifically, the idea of Tally, like, that is something that I think is really cool and really applicable to a lot of codebases. JOËL: So, for those who are interested in more practically what this code looks like, I've put this all in a Gist, and I'll link to it in the show notes. This was a really fun exercise for me because I used sort of two development techniques to help sort of build this out. One, I went with a kind of literate programming approach, where I had just a Ruby file and would have put in some big comment blocks talking about what the setup was, what I was trying to do, and then describing how I'd like to use the code, and then try to write code that made that happen. And then, for the actual objects that I was using under the hood, I used TDD to test drive and build them out. So you've got all of that in the Gist. We've got the tests and that sort of literate programming script that almost reads like a mini blog post, except it's executable Ruby. So, if you're curious to see about that, the link is in the show notes. STEPHANIE: That's a very cool format. I'm excited to take a look. On that note, shall we wrap up? JOËL: Let's wrap up. STEPHANIE: Show notes for this episode can be found at bikeshed.fm. JOËL: This show has been produced and edited by Mandy Moore. STEPHANIE: If you enjoyed listening, one really easy way to support the show is to leave us a quick rating or even a review in iTunes. It really helps other folks find the show. JOËL: If you have any feedback for this or any of our other episodes, you can reach us @_bikeshed, or you can reach me @joelquen on Twitter. STEPHANIE: Or reach both of us at hosts@bikeshed.fm via email. JOËL: Thanks so much for listening to The Bike Shed, and we'll see you next week. ALL: Byeeeeeee!!!!!!! ANNOUNCER: This podcast is brought to you by thoughtbot, your expert strategy, design, development, and product management partner. We bring digital products from idea to success and teach you how because we care. Learn more at thoughtbot.com.

The Doctor, Steven, and Dodo arrive on an Ark...in space! The remnants of the human race has joined forces with a race known as the Monoids. Together, they have fled Earth before it is overtaken by the Sun and are heading to the planet Refusis 2 where they hope to re-establish civilization.  Unfortunately, Dodo has a cold....and the humans and Monoids of the distant future have no resistance to the virus.... STEVEN: Look, do you think this has happened before? That we've carried an infection from one age to another, or even one planet to another?DOCTOR: Oh, I don't want to think it about it, dear boy. It's too horrifying. Though I must say that we're usually very healthy.STEVEN: It'll spread through the whole ship, become an epidemic.___________STEVEN: And that, unfortunately, tells me only one thing...That the nature of man, even in this day and age, hasn't altered at all. You still fear the unknown, like everyone else before you.______________________________DOCTOR: He's right. A long time ago, your ancestors accepted responsibility for the welfare of these Monoids. They were treated like slaves. So no wonder when they got the chance, they repaid you in kind.REFUSIAN: Unless you learn to live together, there is no future for you on Refusis.DASSUK: We understand.DOCTOR: Yes, you must travel with understanding as well as hope. You know, I once said that to one of your ancestors, a long time ago. Upcoming:Serial #24 The Celestial Toymaker(Episodes: "The Celestial Toyroom," "The Hag of Dolls," "The Dancing Floor," "The Final Test"All missing EXCEPT episode 4, "The Final Test")Monday, October 10thVanquishing Villains #2: The First Doctor vs MegalomaniacsA special look back on all the larger-than-life megalomaniacs of the First Doctor's era.Monday, October 17thSpecial thanks to Cathlyn "Happigal" Driscoll for providing the beautiful artwork for this podcast. You can view her work at https://www.happigal.com/ Do feel free to get in touch to share the love of all things Doctor Who: throughthevortexpodcast@gmail.com

Keep an eye out - we're talking Monoids this time!

Keep an eye out - we're talking Monoids this time!

Time Ram unleashes the cloister bell as we face our impossible mission: turning A Good Man Goes to War into a Patrick Troughton story! Find out what happens when a format we haven't given enough thought to turns around and bites us on the a***! Suddenly we find ourselves in a world of pervert scientists and hyper-babies, a cheap 2001 and craving the claw! A world of Monoids, Menoptra, Sensorites and Visians, where only the Meddling Monk can save us! As we move from Easy Yellow to Moderate Red Alert, open heart surgery begins to look simple. This can't be Time Ram... This must be Time Disease.

Back to The Ark we go, and find invisible Refusians, Monoid civil war and wonder how many Monoids there really are and why do some of them not have numbers? And what's cooking in the security kitchen?

The Earth is dying and all the animals are loaded onto a generation ship two by two, along with the entire Human race and their allies the Monoids. This week Paddy and Tricia discuss the first adventure of the new TARDIS crew as they prove to be both the potential destroyers and saviours of The Ark.

Welcome to Regenerated and welcome to Episode 24, in this one Matt and  Beckie take a look The Ark  The Doctor and his companions arrive, on board a giant Ark spaceship, But Dodo has brought with her the common cold which could prove devastating to these future humans and their servants, the Monoids  welcome to regenerated  thank you for listening    (Disclaimer there is talk of Covid-19 and a small amount of death talk)  merchandise -https://teespring.com/en-GB/stores/regenerated       facebook - www.facebook.com/regenerateddoctorwhopodcast/       twitter - twitter.com/Regenerated1963       website - regenerated1963.wixsite.com/regenerated     patreon - patreon.com/regenerated

As Season Three comes to an end it's time to honour the characters and moments that stood out for us. Who will take a place in our hall of fame? Dodo or Katarina? Steven or Charlie the barman? Chumblies or Monoids?  This episode was produced at The Post Office Tower by Professor Brett. 

Sara Lichtenstein, Cameron Gera, and Taylor Fausak get recursively drunk on semigroups and monoids. - https://dev.to/sshine/getting-recursively-drunk-with-monoids-2jek

In the second part of their look at the consequences of time travel, Ben and Mark travel thousands of years in the future to tackle 'The Ark' - a Doctor Who story that seems as relevant as ever. As the humans and Monoids cope with a deadly disease, Mark ponders the blame game in the current COVID-19 pandemic and wonders if the Monoids represent some hope for us all. Meanwhile, an Elizabeth Sandifer piece forms the crux of a discussion of the serial's racial politics and how deliberate half of it actually is. Slavery, racism, class uprisings and deadly pandemics all discussed with a good quantity of wine and whisky in their bellies. What could possibly go wrong?

Everyone talks about monads but monoids are where it’s at. Monoids are simple and make distributed computation a breeze. In this episode, we learn the two properties that make an operation a monoid, and how to use it do distributed computation.

Hoje é dia de revisar The Ark com o 1º Doutor, Steven e Dodo! No futuro distante, a Terra será destruída e os humanos encontraram um planeta para sobreviver, Refusis. Eles estão indo para seu destino a bordo de uma nave que leva toda a humanidade e os animais da Terra, além de uma raça alienígena chamada Monoids. Dodo passando gripe pra geral, um elefante no set, amigos invisíveis e bomba escondida na estátua!

We've tackled Semigroups, and with a little more effort we can better understand Monoids too. With all this momentum we'll cover parameterized types and the Maybe type too.

Sticking with Types, we dive deeper with sum and product types, we hit on Semigroup and start to unwind Monoids!

We watch another old episode, one of the only ones available on video in its entirety from this season, The Ark (not to be confused with The Ark in Space which starred Tom Baker as the Doctor from season 12). The Doctor, William Hartnell, along with Dodo and Steve land in an Ark ship carrying the human race from a doomed Earth following the expansion of the sun as it started to die. Interestingly, this means the Doctor has been witness to both the start of their journey by having been on Platform One to witness the end of Earth in the First Season of the Ninth Doctor and the end of their journey to the planet Refusis II. The Ark is piloted by the Guardians while most of the humans are in stasis miniaturized. Also brought along are many flora and fauna form Earth as well as the Monoids. An alien race which the humans have enlisted as servants. The Doctors companions bring along a cold which threatens the ship since the humans and Monoids have no immunity to this virus anymore. Once solved they leave only to end up back on the Ark 700 years later where they find the roles have reversed on the ship in the intervening time as they approach their destination with the Monoids being cruel masters to their Guardian slaves, and they find the planet not as uninhabited as they think it is. If you like us, Follow us on Twittter @DWDont_Blink , Facebook @DWDontBlink, and Instagram at dwdont_blink. Also feel free to write us a review on Google Play or iTunes.Original Posting Date: Thu, 08 Jun 2017

Julie Moronuki: @argumatronic | argumatronic.com Show Notes: This episode is a follow-up episode to the one we did with Julie in September: Learn Haskell, Think Less. We talk a whole lot about monoids, and learning programming languages untraditionally. Transcript: CHARLES: Hello everybody and welcome to The Frontside Podcast, Episode 93. My name is Charles Lowell, a developer here at The Frontside and I am your podcast host-in-training. With me today from The Frontside is Elrick also. Hello, Elrick. ELRICK: Hey. CHARLES: How are you doing? ELRICK: I'm doing great. CHARLES: Alright. Are you ready? ELRICK: Oh yeah, I'm excited. CHARLES: You ready to do some podcasting? Alright. Because we actually have a repeat guest on today. It was a very popular episode from last year. We have with us the author of ‘Learning Haskell: From First Principles' and a book that is coming out but is not out yet but one that we're eagerly looking forward to, Julie Moronuki. Welcome. JULIE: Hi. It's great to be back. CHARLES: What was it about, was it last October? JULIE: I think it was right before I went to London to Haskell [inaudible]. CHARLES: Yeah. JULIE: Which was in early October. So yeah… CHARLES: Okay. JULIE: Late or early October, somewhere in there. CHARLES: Okay. You went to Haskell eXchange. You gave a talk on Monoids. What have you been up to since then? JULIE: Oh wow. It's been a really busy time. I moved to Atlanta and so I've had all this stuff going on. And so, I was telling a friend last night “I'm going to be on this podcast tomorrow and I don't think I have anything to talk about.” [Laughter] JULIE: Because I feel like everything has just been like, all my energy has been sucked up with the move and stuff. But I guess… CHARLES: Is it true that everybody calls it ‘Fatlanta' there? JULIE: Yeah. [Laughs] CHARLES: I've heard the term. But do people actually be like “Yes, I'm from Fatlanta.” JULIE: I've heard it a couple of times. CHARLES: Okay. JULIE: Maybe it's mostly outsiders. I'm not sure. CHARLES: [Chuckles] JULIE: But yeah, it's a real cool city and I'm real happy to be here. But yeah, I did go in October. I went to London and I spoke at Haskell eXchange which was really amazing. It was a great experience and I hope to be able to go back. I got to meet Simon Payton Jones which was incredible. Yeah, and I gave a talk on monoids, monoids and semirings. And… CHARLES: Ooh, a semiring. JULIE: Semiring. So, a semiring is a structure where there's two monoids. So, both of them have an identity element. And the identity element of one of them is an annihilator. Isn't that a great word? It's an annihilator… CHARLES: Whoa. JULIE: Of the other. So, if you think of addition and multiplication, the identity element for addition is zero, right? But if you multiply times zero, you're always going to get to zero, so it's the annihilator of multiplication. CHARLES: Whoa. I think my mind is like annihilated. [Laughter] JULIE: So, it's a structure where you're got two monoids and one of them distributes over the other, the distributive property of addition and multiplication. And the identity of one of them is the annihilator of the other. Anyway, but yeah, I gave a history of where monoids come from and that was really fun. CHARLES: Yeah. I would actually like to get a summary of that, because I think since we last talked, I've been getting a little bit deeper and deeper into these formal type classes. I'm still not doing Haskell day-to-day but I've been importing these ideas into just plain vanilla JavaScript. And it turns out, it's actually a pretty straightforward thing to do. There's definitely nothing stopping these things from existing in JavaScript. It's just, I think people find type class programming can be a tough hill to climb or something like that, or find it intimidating. JULIE: Yeah. CHARLES: But I think it's actually quite powerful. And I think one of the things that I'm coming to realize is that these are well-worn pathways for composing things. JULIE: Right. CHARLES: So, what you encounter in the wild is people generating these one-off ways of composing things. And so, for a shop like ours, we did a lot of Ruby on Rails, a lot of Ember, and both of those frameworks have very strong philosophical underpinnings that's like “You shouldn't be reinventing the wheel if you don't have to.” I think that all of these patterns even though they have crazy quixotic esoteric names, they are the wheels, the gold standard of wheel. [Laughs] They're like… JULIE: Right. CHARLES: We should not be reinventing. And so, that's what I'm coming to realize, is I'm into this. And last time you were talking, you were saying “I find monoids so fascinating.” I think it took a little bit while to seep in. But now, I feel like it's like when you look at one of those stereo vision things, like I'm seeing monoids everywhere. It's like sometimes they won't leave me alone. JULIE: In ‘Real World Haskell' there's a line I've always liked. And I'm going to misquote it slightly but paraphrasing at least. “Monoids are ubiquitous in programming. It's just in Haskell we have the ability to just talk about them as monoids.” CHARLES: Yeah, yeah. JULIE: Because we have a name and we have a framework for gathering all these similar things together. CHARLES: Right. And it helps you. I feel like it helps you because if you understand the mechanics of a monoid, you can then when you encounter a new one, you're 90% there. JULIE: Right. CHARLES: Instead of having to learn the whole thing from scratch. JULIE: Right. And as you see them over and over again, you develop a kind of intuition for when something is monoidal or something looks like a semiring. And so, you get a certain intuition where you think, “Oh, this thing is like a… this is a monad.” And so, what do I know about monads? All of a sudden, this new situation like all these things that I know about monads, I can apply to this new situation. And so, you gain some intuition for novel situations just by being able to relate them to things you already do know. CHARLES: Exactly. I want to pause here for people. The other thing that I think I've come in the last three months to embrace is just embrace the terminology. JULIE: Yeah. CHARLES: You got to just get over it. JULIE: [Chuckles] CHARLES: Think about it like learning a foreign language. The example I give is like tasku is the Finnish word for pocket. JULIE: Right. CHARLES: It sounds weird, right? Tasku. But if you say it 10 times and you think “Pocket, pocket, pocket, pocket, pocket.” JULIE: Yes, yeah. [Laughs] CHARLES: Then it's like, this is a very simple, very useful concept. JULIE: Right. CHARLES: And it's two-sided. There on the one hand, the terminology is obtuse. But at the same time, it's not. It's just, it is what it is. And it's just a symbol that's referencing a concept. JULIE: Right, right. CHARLES: It's a simple concept. So, I just want to be… I know for our listeners, I know that there's a general admonition. Don't worry about the terminology. It's… JULIE: Right, right. Like what I just said, I said the word ‘monad'. I just threw that out there at everybody, but [chuckles] it doesn't matter which one of these words we'd be talking about or whatever I call them. We could give monads a different name and it's still this concept that once you understand the concept itself, and then you can apply it in new situations, it doesn't matter then what it's called. But it does take getting used to. The words are… well, I think functor is a pretty good word for what it is. If you know the history of functor and how it came to mean what it means, I think it's a pretty good word. CHARLES: Really? So, I would love to know the history. Because functor is mystifying to me. It sounds like, I think the analogy I use is like if George Clinton and a funk parliament had an empire, the provinces, the governors of the provinces would be functors. ELRICK: [Laughs] JULIE: Yes. CHARLES: But [Laughs] that's the closest thing to an explanation I can come up with. JULIE: I might use that. I'm about to give a talk on functors. I might use that. [Laughter] ELRICK: Isn't that the name of the library? Funkadelic? CHARLES: Well, that's the name of the library that I've been… JULIE: [Could be], yeah. ELRICK: That you'd been… CHARLES: That I'd been [writing] for JavaScript. ELRICK: Yeah. CHARLES: That imports all these concepts. JULIE: [Laughs] ELRICK: Yeah. JULIE: Yeah. ELRICK: So awesome. JULIE: Yeah. Yeah, I have… CHARLES: So, what is the etymology of functor? JULIE: Well, as far as I can tell, Rudolf Carnap, the logician, invented the word. I don't know if he got it from somewhere else. But the first time I can find a reference to it is in, he wrote a book about… he was a logician but this is sort of a linguistics book. It's called ‘The Logical Syntax of Language'. And that's the first reference I know of to the word functor. And he was trying to really make language very logically systematic, which natural language is and isn't, right? [Chuckles] CHARLES: Right. JULIE: But he was only concerned with really logically systematizing everything. And so, he used the word functor to describe some kinds of function words in language that relate one part of a sentence to another part of a sentence. CHARLES: Huh. So, what's an example? JULIE: So, the example that I've used in the past is, as far as I know this is not one that Carnap himself actually uses but it's the clearest one outside of that book… well the ones inside the book I don't really think are very good examples because they're not really how people talk. So, the one that I've used to try to explain it is the word ‘not' in English where ‘not' gets applied to the whole sentence. It doesn't really change the logical structure of the sentence. It doesn't change the meaning of the sentence except for now it negates the whole thing. CHARLES: I see. JULIE: And so, it relates this sentence with this structure to a different context, which is now the whole thing has been negated. CHARLES: I see. So, the meaning changes, but the structure really doesn't. JULIE: Right. And it changes the whole meaning. CHARLES: Right. JULIE: Not just part of the sentence. So, if you imagine ‘not' applying to an entire sentence because of course we can apply it just to a single word or just to a single phrase and change the meaning just of that word or that phrase, but if you imagine a context where you've applied ‘not' to a whole sentence, to an entire proposition, because of course he's a logician. So, if you've applied ‘not' to an entire proposition, then it doesn't change the structure or the meaning of that proposition per se except for it just relates it to the category of negated propositions. CHARLES: Mmhmm. JULIE: So, that's where it comes from. And… CHARLES: But I still don't understand why he called it functor. JULIE: He's sort of making up… well, actually I think the German might be the same word. CHARLES: Ah, okay. JULIE: Because he was writing in German. Because he's looking for something that evokes the idea of ‘function word'. CHARLES: Oh. JULIE: So, if you were to take the ‘func' of ‘function' [Laughs] and the, I don't know, maybe in German there's some better explanation for making this into a particular word. But that's how I think of it. So, it's ‘function word'. And then category theorists took it from Carnap to mean a way to map a function in this category or when we're talking about Haskell, a function of this type, to a function of another type. CHARLES: Okay. JULIE: And so, it takes the entire function, preserves the structure of the function just like negation preserves the structure of the sentence, and maps the whole thing to just a different context. So, if you had a function from A to B, functor can give you a function from maybe A to maybe B. CHARLES: Right. JULIE: So, it takes the function and just maps it into a different context. CHARLES: Right. So, a JavaScript example is if I've got an array of ints and a function of ints to strings, I can take any array of ints and get an array of strings. JULIE: Right. CHARLES: Or if I have a promise that has an int in it, I can take that same function to get a promise of a string. JULIE: Yeah. CHARLES: Yeah. I had no idea that it actually came from linguistics. JULIE: Yeah. [Laughs] CHARLES: So actually, the category theorists even… it digs deeper than category theory. They were actually borrowing concepts. JULIE: They were, yes. CHARLES: We just always are borrowing concepts. ELRICK: I like the borrowing of concepts. JULIE: Yeah. ELRICK: I think where people struggle with certain things, it's tying it back to something that they're familiar with. So, that's where I get… my mind is like [makes exploding sound] “I now get it,” is when someone ties it back to something that I am… CHARLES: Right. ELRICK: Familiar with. Like Charles' work with the JavaScript, tying it with JavaScript. I'm like, “Oh, now I see what they're talking about.” JULIE: Right. CHARLES: because you realize, you're using these concepts. People are using them, just they're using them anonymously. JULIE: Right. ELRICK: True. CHARLES: They don't have names for them. JULIE: Right. ELRICK: True. CHARLES: It's literally like an anonymous function and you're just taking that lambda and assigning it to a symbol. JULIE: Yeah. CHARLES: You're like “Oh wait. I've been using this anonymous function all over the place for years. I didn't realize. Boom. This is actually a formal concept.” ELRICK: True. And I think when people say like “Don't reinvent the wheel” it's a great statement for someone that has seen a wheel already. [Laughter] ELRICK: You know what I'm saying? If you never saw a wheel, then your'e going to reinvent the wheel because you're like “Aw man. This doesn't exist.” [Chuckles] JULIE: Yeah. ELRICK: But if people are exposed to these concepts, then they wouldn't reinvent the wheel. CHARLES: Right. JULIE: Right. Yeah. CHARLES: Instead of calling in some context, calling it a roller. [Chuckles] It's a round thingy. [Laughter] JULIE: Right. Yeah, so that's a little bit what I tried to do in my monoid talk in London. I tried to give some history of monoid, where this idea comes from and why it's worth talking about these things. CHARLES: Yeah. JULIE: Why it's worth talking about the structure. CHARLES: So, why is it worth the… where did it come from and why is it worth talking about? JULIE: Oh, so back when Boole, George Boole, when he decided to start formalizing logic… CHARLES: George Boole also, he was a career-switcher too, right? He was a primary school teacher. JULIE: Right, yeah. CHARLES: If I recall. He actually, he was basically teaching. Primary school is like elementary school in England, right? JULIE: I believe so, yes. CHARLES: Yeah. I think he was like, he was basically the US equivalent of an elementary school teacher who then went on to a second and probably, thankfully a big career that left a big legacy. JULIE: Right. Although no one knew exactly how big the legacy was really, until Claude Shannon picked it up and then just changed the whole world.[Laughs] Anyway, so Boole, when he was trying to come up with a formal algebra of logic so that we could not care so much about the semantic content of arguments (we could just symbolize them and just by manipulating symbols we could determine if an argument was logically valid or not), he was… well, for disjunction and conjunction which is AND and OR – well, disjunction would be the OR and conjunction the AND – he had prior art. He had addition and multiplication to look at. So, addition is like disjunction in some important ways. And multiplication is like conjunction in some important ways. And I think it took me a while to see how addition and disjunction were like each other, but there are some important ways that they're like each other. One of them is that they share their identity values. If you think of, it's sort of like binary addition and binary multiplication because in boolean logic there's only two values: true or false. So, you have a zero and a one. So, if you think of them as being like binary addition and binary multiplication then it's easier to see the connection. Because when we think of addition of just integers in a normal base 10 or whatever, it doesn't seem that much like an OR. [Laughs] CHARLES: Mmhmm. No, it doesn't. JULIE: [Inaudible] like a logical OR. So, it took me a while to see that. But they're also related then to set intersection and union where intersect-… CHARLES: So can… Let's just stop on that for a little bit, because let me parse that. So, for OR I've got two values, like in an ‘if' statement. This OR that. If I've got a true value then I can OR that with anything and I'll get the same anything. JULIE: Right. CHARLES: So, true is the identity value of OR, right? Is that what you're saying? So, one… JULIE: Well, it's false that's the identity of OR. CHARLES: Oh, it is? JULIE: Zero is the identity of addition. CHARLES: Wait, but if I take ‘false OR one' I get… oh, I get one. JULIE: Right. CHARLES: Okay. So, if I get ‘false OR true', I get true. Okay, so false is the identity. JULIE: Yeah. CHARLES: Oh right. You're right. You're right. Because… okay, sorry. JULIE: So, just like in addition, zero is the identity. So, whatever you add to zero, that's the result, right? You're going to get [the same] CHARLES: Right. JULIE: Value back. So, with OR false is the identity and false is equivalent to zero. CHARLES: [Inaudible] ‘False OR anything' and you're getting the anything. JULIE: Right. So, the only time you'll get a false back is if it's ‘false OR false', right? CHARLES: Right. Mmhmm. JULIE: Yeah. So, false is the identity there. And then it's sort of the same for conjunction where one is the identity of multiplication and one is also the… I mean, true is then the identity of logical conjunction. CHARLES: Right. Because one AND… JULIE: ‘True AND false' will get the false back. [Inaudible] CHARLES: Right. ‘True And true' you can get the true back. JULIE: Yeah. CHARLES: Okay. JULIE: And it's also then true, getting back to what we were talking about, semirings, it's also true that false is a kind of annihilator for conjunction. That's sort of trivial, because… CHARLES: Oh, because you annihilate the value. JULIE: Right. When there's only two values it's a little bit trivial. But it is [inaudible]. So… CHARLES: But it's [inaudible]. Yeah. It demonstrates the point. JULIE: Right. CHARLES: So, if I have yeah, ‘false AND anything' is just going to be false. So, I annihilate whatever is in that position. JULIE: Right. CHARLES: And the same thing as zero is the annihilator for multiplication, right? JULIE: Right. CHARLES: Because zero times anything and you annihilate the value. JULIE: Yeah. CHARLES: And now I've got… okay, I'm seeing it. I don't know where you're going with this. [Laughter] ELRICK: Yeah. CHARLES: But I'm there with you. ELRICK: Yup. JULIE: And then it turns out there are some operations from set theory that work really similarly. So, intersection and union are similar but the ones that are closer to conjunction/disjunction are disjoint unions and cartesian products. So we don't need to talk about those a whole lot if you're not into set theory. But anyway… CHARLES: I like set theory although it's so hard to describe without pictures, without Venn diagrams. JULIE: It is. It really is, yeah. So anyway, all of these things are monoids. And they're all binary associative operations with identity elements. So, they're all monoids. And so, we've taken operations on sets, operations on logical propositions, operations on many kinds of numbers (because not all kinds of addition and multiplication I guess are associative), and we can kind of unify all of those into the same framework. And then once we have done that, then we can see that there's all these other ‘sets'. Because most of the kinds of numbers are sets and there are operations on generic sets with set theory. So, now we can say “Oh. We can do these same kinds of operations on many other kinds of sets, many other varieties of sets.” And we can see that same pattern. And then we can get a kind of intuition for “Well, if I have a disjunctive monoid where I'm adding two things or I'm OR-ing two things…” Because even though those are logically very similar, intuitively and in terms of what it means to concatenate lists versus choosing one or the other, those obviously have different practical effects. CHARLES: So, I'm going to try and come up with some concrete examples to maybe… JULIE: Okay, yeah. CHARLES: A part of them will probably be like in JavaScript, right? So, to capture the idea of a disjunctive monoid versus a conjunctive monoid. So, a disjunctive monoid is like, so in JavaScript we're got two objects. You concat them together and it's like two maps or two hashes. So, you mash them together and you get… so, for the disjunctive one you'd have all the keys from both of the hashes inside the resulting object. You take two objects. Basically we call it object assign in JavaScript where you have basically the empty object. You can take the empty object and then take any number of objects. And so, we talked about… JULIE: That would become a disjunctive monoid, right? CHARLES: That would be a disjunctive monoid because you're like basically, you're OR-ing. Yeah. JULIE: You're kind of, [inaudible] CHARLES: Hard to find the terminology. JULIE: Yeah. CHARLES: But like object assign would be a disjunctive monoid because you're like mashing these two objects. And the resulting object has all of the things from both of them. JULIE: Right. So, it's like a sum of the two, right? CHARLES: Right, right. Okay, so then another one would be like min or max where you've got this list of integers and you can basically take any two integers and you can mash them together and if you're using min, you get the one that's smaller. Basically, you're collapsing them into one value but you're actually just choosing one of them. Is that like… JULIE: Yeah. CHARLES: Would that be like a conjunctive monoid? JULIE: No, that's also disjunctive but that's more like an OR than like a sum. CHARLES: Okay. JULIE: Right. So, that's what I said. It's hard to think of disjunctive monoids I think because there's really two varieties. There's some underlying logical similarity, like the similarity in the identity values. But they're also different. Summing two things versus choosing one or the other are also very different things in a lot of ways. CHARLES: Right. Okay. JULIE: And so, I think the conjunctive monoids are all a little bit more similar, I think. [Chuckles] But the disjunctive monoids are two broad categories. And we don't really have a monoid in Haskell of lists where you're choosing one or the other. The basic list monoid is you're concatenating them. So, you're adding two lists or taking the union of them. But for maybe, the maybe type, we do have monoids in Haskell where you're just choosing either the first just value that comes up or the last just value that comes up. So, we do have a monoid of choice over the maybe type. And then we have a type class called alternative which is monoids of choice for… so, they're disjunctive monoids but instead of adding the two things together, they're choosing one or the other. CHARLES: Okay. JULIE: Though we have a type class for that. [Laughs] CHARLES: [Sighs] Oh wow. Yeah. JULIE: Mmhmm, yeah. CHARLES: I'l have to go read up on that one. JULIE: That type class comes up the most when you're parsing, because you can then parse… like if you found this thing, then parse this thing. But if you haven't found this thing, then you can keep going. And if you find this other thing later, then you can take that thing. So, you allow the possibility of choice. The first thing that you come to that matches, take that thing or parse that thing. So, that type class gets mostly used for parsing but it's not only useful for parsing. CHARLES: Okay. JULIE: So yeah. That's the most of the time when I've used it. CHARLES: Is this when you're like parsing JSON? Or is this when you're just searching some stream for some value? Like you just want to run through it until you encounter this value? Or how does that…? JULIE: Right. Say you want to run through it until you find either this value or this value. I've used it when I've been parsing command line arguments. So, let's say I have some flags that can be passed in on my command line command. There are some flags that could be passed in. So, we'll parse until we find this thing or this thing. This flag or this flag. So, if you find this flag, then we're going to go ahead and parse that and do whatever that flag says to do. If you don't find that first flag then we can keep parsing and see if you find this other flag, in which case we'll do something different. CHARLES: Okay. JULIE: It'll take the first match that it finds. Does that make sense? CHARLES: Yeah, yeah, yeah. It does. But I'm not connecting how it's a monoid. [Laughs] JULIE: How is that a monoid? Well, because it's a monoid of OR-ing CHARLES: What's the identity value or the empty value in that case? JULIE: Well, the empty value would be… let's say you have maybes. Let's say you have some kind of maybe thing, so you're parser is going to return maybe this thing, maybe whatever you're parsing. Like maybe string. CHARLES: Yeah, yeah. JULIE: So, it's going to return a maybe string. So well, nothing would be the empty. CHARLES: Okay. JULIE: But nothing is like the zero because it's a disjunction, logical OR. So, only when you have two nothings will you get back a nothing. Otherwise, it will take the first thing that it finds. CHARLES: Okay. I see. JULIE: Yeah. So, the identity then is the nothing, like false is the identity for disjunction. CHARLES: Mmhmm. Okay. JULIE: Yeah. CHARLES: [Inaudible] JULIE: Yeah. If you have nothing or this other thing, then you return this other thing. Then you return the maybe string. If you have two nothings, then you get in fact nothing. Your parsing has failed. CHARLES: Right, because you've got nothing. JULIE: Because you've got nothing. There was nothing to give you back. CHARLES: So, you concatenated all of the things together and you ended up with nothing. JULIE: Right, because there was nothing there. CHARLES: Right. [Laughs] JULIE: You found nothing. So, it's useful when you've got some possibilities that could be present and you just want to keep parsing until you find the first one that matches. And then it'll just return whatever. It'll just parse the first thing that it matches on. CHARLES: Okay, okay. JULIE: Does that make sense? CHARLES: Yeah. No, I think it makes sense. JULIE: I'm not sure. Because I feel like I kind of went down a rabbit hole there. [Laughs] CHARLES: Yeah. [Laughs] No, no. I think it makes sense. And as a quick aside, I think… so, I was, when we were talking about min and max, are min and max also like a semiring? Because negative infinity is the annihilator of min and it's the identity of max. and positive infinity is the annihilator of max but it's the identity of min. JULIE: I guess. I don't really think of min and max as having identities. Is that how [inaudible]? CHARLES: I'm just, I don't know. Well, I think if you have negative infinity and you max it with anything, you're going to get the anything, right? Negative infinity max one is one. Negative infinity/minus a billion is minus a billion. JULIE: Yeah, okay. CHARLES: I don't know. Just off the cuff. I'm just trying to… annihilators sound cool. And so… [Laughter] CHARLES: And so I'm like, I'm trying to find annihilators. JULIE: Yeah, they are cool. CHARLES: [Laughs] JULIE: One of my friends on Twitter was just talking about how he used the intuition at least of a semiring at work because he had this sort of monoid to concatenate schedules. So, he's got all these different schedules and he's got this kind of monoid to concatenate them, to merge the schedules together. But then he's got this one schedule that is special. And whenever something is in this schedule, it needs to hard override every other schedule. CHARLES: Right. JULIE: And so, that was like the annihilator. So, he was thinking of it as a semiring, because that hard override schedule is like the annihilator of all the other schedules. CHARLES: Yeah. JULIE: If anything else exists on this day or whatever, then it'd just get a hard override. So, there's a real world use. [Laughs] CHARLES: Yeah, a real world example. That's the thing that I'm finding, is that all these really very crystalline abstractions, they still play out very well I think in the real world. And they're useful as a took in terms of casting a net over a problem. Because you're like… when I'm faced with something new, I'm like “Well, let's see. Can I make it a functor?” And if I can, then I've unlocked all these goodies. I've unlocked every single composition pattern that works with functor. JULIE: Right, right. CHARLES: And it's like sometimes it fits. It almost feels like when you're working on something at home and you've got some bolt and you're trying on different diameters. So you're like, “Oh, is it 15 millimeter? Is it 8 millimeter?” JULIE: Right. [Laughs] CHARLES: “Like no, okay. Maybe it'll work with this.” But then when it clicks, then you can really ratchet with some serious torque. JULIE: Right, right. Yeah. CHARLES: So, yeah. Definitely trying to look for semirings [Laughs] is definitely beyond my [can] at this point. But I hope to get there where it can be like, if it's a fit, it's a fit. That's awesome. JULIE: Right. Yeah, it's kind of beyond my can too. Semirings are still a little bit new for me and I can't say that I find them in the wild as it were, as often as monoids or something. But I think it just takes seeing some concrete examples. So, now you know this idea exists. If you just have some concrete examples of it, then over time you develop that intuition, right? CHARLES: Right. JULIE: Like “Okay, I've seen this pattern before.” [Chuckles] CHARLES: yeah. Basically, every time now I want to fold a list, or like in JavaScript, any time you want to reduce something I'm like “There's a monoid here that I'm not seeing. Let me look for it.” JULIE: Yeah. Oh, that's cool, yeah. CHARLES: Because like, that's basically, most of the time you're doing a reduce, then like I said that's the terminology for fold in JavaScript, is you start with some reducible thing. Then you have an initial value and a function to actually concatenate two things together. JULIE: Right. CHARLES: And so, usually that initial state, that's your identity. And then that function is just your concat function from your monoid. And so, usually anytime I do a reduce, there's the three pieces. Boom. Identity value, concatenation function, it's usually right there. And so, that's the way I've found of extracting these things, is I'm very suspicious every time I'm tempted to… JULIE: [Laughs] CHARLES: A fold. I'm like “Hmm. Where's the monoid I'm missing? Is it [under the] couch?” Like, where is it? [Laughs] Because it just, it cleans it up and it makes it so much more concise. JULIE: Oh yeah, that's awesome. CHARLES: So anyhow. JULIE: Have we totally lost Elrick? ELRICK: Nope, I'm still here. JULIE: Okay. [Laughs] ELRICK: I'm sitting in and listening to you two break down these complex topics is really good. Because you guys break them down to a level where it's consumable by people that barely understand it. So, I'm just sitting here just soaking everything in like “Oh, that's awesome.” Taking notes. Yes, okay, okay. [Laughter] JULIE: Cool. ELRICK: So, I'm like riding the train in the back just hanging out, feeling the cool breeze while you guys just pull the train ahead in… [Laughter] ELRICK: In the engine department, you know? It's awesome. CHARLES: Yeah. ELRICK: I don't know if they're related. But you were talking about semirings and I heard of semigroups or semigroups. I have no idea if those two things are related. Are they related or [inaudible]? JULIE: They're kind of related. So, a semigroup is like a monoid but doesn't have an identity value. CHARLES: What is an example of a semigroup out there in the wild? Because every time I find a semigroup, I feel like it's actually a monoid. JULIE: Well, you know I feel like that a lot, too. We do have a data type in Haskell that is a non-empty list. So, there is no empty list CHARLES: Ah, right. Okay. JULIE: So then you can concatenate those lists, but there's never an identity value for it. CHARLES: I see. JULIE: Yeah. So, that's a case. There's actually a lot of comparison functions, greater than and less than. I think those are semigroups because they're binary, they're associative, but they don't have an identity value. Like if you're comparing two numbers, there's not really an identity value there. CHARLES: Right. Well, would the negative infinity work there? Let's see. Like, negative infinity greater than anything would be the anything. Well, okay wait. But greater than, that takes numbers and yields a boolean, right? JULIE: Yeah, CHARLES: Right. So, it couldn't be… could it be a semigroup? Don't semigroups have to… Doesn't the [inaudible] function have to yield the same type as the operands? JULIE: Yes. CHARLES: But a non-empty list, that's a good one. Sometimes it's basically not valid for you to have a list that doesn't have any elements, right? Because it's like the null value or the empty value and it could be like a shopping cart on Amazon. You can't have a shopping cart without at least something in it. JULIE: Right. CHARLES: Or, you can't check out without something. So, you might want to say like the shopping cart that I'm going to check out is a non-empty list. And so, you can put two non-empty lists together. But yeah, there's no value you can mash together, you can concat with anything, that isn't empty. JULIE: Right. CHARLES: So, I guess going back to your question Elrick, I don't know if it's related to semiring. But semigroup is just, it's like one-half of monoid. It's the part that concats two values together. JULIE: Right. Well, yeah. And so, it's supposed to be half a group, right? But I don't remember… CHARLES: [Laughs] JULIE: [Inaudible] all of the group stuff is, all the stuff that these types have to have to be a group. And similarly, I forget what the difference between semiring and ring is. [Chuckles] Because a ring and a group I know are not the same thing. But I forget what the difference is, too. So, I kind of got a handle on what semigroups are, and I know all my Haskell friends are going to, when they hear this podcast they're going to tweet all these examples of semigroups at me, especially my coauthor for ‘Joy of Haskell', Chris Martin. He's really into semigroups. And so, I know he's going to be very disappointed in my inability to think… [Laughter] JULIE: To think of any good examples. But it's not something that I find myself using a lot, whereas semirings are something that I have started noticing a little bit more often. So, how a monoid relates to a group is something that I can't remember off the top of my head. And I know how semirings relate to monoids, but how monoids then relate to rings and groups, I can't really remember. And so, these things are sort of all related. But the relation is not something I can spill out off the top of my head. Sorry. [Laughs] CHARLES: No, It's no worries. You know, I feel like… ELRICK: It's all good. CHARLES: What's funny is I feel like having these discussions is exactly like the discussions people have with any framework of using one that we use a lot, which is EmberJS. But if you could do with React or something, it's like, how does the model relate to the controller, relate to the router, relate to the middleware, relate to the services? You just have these things, these moving parts that fit together. And part of… I feel like exploring this space is really, absolutely no different than exploring any other software framework where you just have these things, these cooperating concepts, and they do click together. But you just have to map out the space in your head. JULIE: Yeah. This is going to sound stupid because everybody thinks that because I know Haskell I must know all these other things. But I just had to ask people to recommend me a book that could explain the relationship of HTML and CSS, because that was completely opaque to me. CHARLES: [Laughs] Yeah. JULIE: I've been involved in the making now of several websites because of the books and stuff like that. And I have a blog. It's not WordPress or anything. I did that sort of myself. So, I've done a little bit with that. But CSS is really terrifying. And… CHARLES: Right. Like query selectors, rules, properties. JULIE: Yeah. ELRICK: [Laughs] CHARLES: Again, might as well be groups and semigroups and monoids, right? JULIE: Right, right. ELRICK: Yeah. CHARLES: [Laughs] ELRICK: That is really interesting. [Chuckles] I've never heard anyone make that comparison before. But it's totally true, now that I'm thinking about it. JULIE: Yeah, yeah. CHARLES: Yeah. In the tech world we are so steeped in our own jargon that we could be… we can reject one set of jargon and be totally fine with another set. Or be like, suspicious of one set of concepts working together and be totally fine with these other designations which are somewhat arbitrary but they work. JULIE: Right. CHARLES: So, people use them. JULIE: So, it's like what you've gotten used to and what you're familiar with and that seems normal and natural to you. [Chuckles] So, the Haskell stuff, most of it seems normal and natural to me. And then I don't understand HTML and CSS. So, I bought a book. [Laughter] CHARLES: Learning HTML and CSS from first principles. JULIE: Yes, yeah. I just wanted to understand. I could tell that they do relate to each other, that there is some way that they click together. I can tell that by banging my head against them repeatedly. But I didn't really understand how, and so yeah. So, i've been reading this book to [Laughs] [learn] HTML and CSS and how they relate together. That's so important, just figuring out how things relate to each other, you know? CHARLES: Yeah. ELRICK: Yeah. That is very true. JULIE: Yeah. ELRICK: We can trade. I can teach you HTML and CSS and you can teach me Haskell. JULIE: Absolutely. ELRICK: [Laughs] CHARLES: There you go JULIE: [Laughs] ELRICK: Because I'm like, “Ooh.” I'm like, “Oh, CSS. Great. No problem.” [Laughter] ELRICK: Haskell, I'm like “Oh, I don't know.” JULIE: Yeah. CHARLES: Yeah. ELRICK: [Laughs] CHARLES: No, it's amazing [inaudible] CSS. ELRICK: Yeah. CHARLES: It is, it's a complicated system. And it's actually, it's in many ways, it's actually a pretty… it's a pretty functional system, CSS is at least. The DOM APIs are very much imperative and about mutable state. But CSS is basically yeah, completely declarative. JULIE: Right. CHARLES: Completely immutable. And yeah, the workings of the interpreter are a mystery. [Laughs] ELRICK: Yup. JULIE: YEs. And you know, for the Joy of Haskell website we use Bootstrap. And so, there was just like… there's all this magic, you know? [Laughs] ELRICK: Oh, yeah. CHARLES: Yeah. JULIE: Oh look, if I just change this little thing, suddenly it's perfectly responsive and mobile. Cool. [Laughter] JULIE: I don't know how it's doing this, but this is great. [Laughs] CHARLES: Yeah. Oh, yeah. It's an infinite space. And yeah, people forget what is so easy and intuitive is not and that there's actually a lot of learning that happened there that they're just taking for granted. JULIE: I think so many people start from HTML and CSS. That's one of their first introductions to programming, or JavaScript or some combination of all three of those. And so, to them the idea that you would be learning Haskell first and then coming around and being like “Oaky, I have to figure out HTML,” that [seems very] strange, right? [Laughter] CHARLES: Yeah. Well, definitely probably stepping into bizarro world. JULIE: And I went backwards. But [Laughs] CHARLES: Yeah. JULIE: Not that it's backwards in terms of… just backwards in terms of the normal way, progression of [inaudible] CHARLES: Yeah. It's definitely the back door. Like coming in through the catering kitchen or something. JULIE: Yes. CHARLES: Instead of the front door. Because you know the browser, you can just open up the Dev Tools and there you are. JULIE: Exactly, yeah. CHARLES: The level of accessibility is pretty astounding. And so, I think t's why it's one of the most popular avenues. JULIE: Oh, definitely. Yeah. ELRICK: It's the back door probably for web development but not the back door for programming in general. JULIE: Mm, yeah. Yeah. CHARLES: Yeah. It seems like Haskell programming has really started taking off and that the ecosystem is starting to get some of the trappings of a really less fricative developer experience in terms of the package management and a command line experience and being able to not make all of the tiny little decisions that need to be made before you're actually writing ‘hello world'. JULIE: Right. ELRICK: Interesting. Haskell has a package manager now? CHARLES: Oh, it has for a while. ELRICK: Oh, really? What is it called? I have no idea? Do you know the name off the top of your head? CHARLES: So, I actually, I'm not that familiar with the ecosystem other than every time I try it out. So I definitely will defer this question to you, Julie. JULIE: This is going to be a dumb question, I guess. What do we mean by package manager? CHARLES: So, in JavaScript, we have npm. The concept of these packages. It's code that you can download, a module that you can import, basically import symbols from. And Ruby has RubyGems. And Python has pip. JULIE: Okay, okay. CHARLES: Emacs has Emacs Packages. And usually, there's some repository and people could publish to them and you can specify dependencies. JULIE: Right, yeah. Okay, so we have a few things. Hackage is sort of the main package repository. And then we have another one called Stackage and the packages that are in Stackage are all guaranteed to work with each other. CHARLES: Mm, okay. JULIE: So, on Hackage, some of the packages that are on Hackage are not really maintained or they only work with some old versions of dependencies and stuff like that, so the people who made Stackage were like “well, if we had this set of packages that were all guaranteed to work together, the dependencies were all kept updated and they all can be made to work together, then that would be really convenient.” And then we have Cabal and we have Stack are the main… and a lot of people use Nix for the same purpose that you would use Cabal or Stack for building projects and importing dependencies and all of that. CHARLES: Right. So, Cabal and Stack would be roughly equivalent then to the way we use Yarn or JavaScript and Bundler in Ruby. You're solving the equation for, here's my root set of dependencies. Go out and solve for the set of packages that satisfy. Give me at least one solution and then download those packages and [you can] run them. JULIE: Yeah, yeah. Right, so managing your dependencies and building your project. Because Haskell's compiled, so you've got to build things. And so yeah, we have both of those. CHARLES: And now there's like web frameworks and REST frameworks. JULIE: Oh there are, yeah. We have… CHARLES: All kinds of stuff now. JULIE: We had this big proliferation of web frameworks lately. And I guess some of them are very good. I don't really do web development. But the people I know who do web development in Haskell say that some of these are very good. Yesod is supposed to be very good. Servant is sort of the new hotness. And I haven't used Servant at all though, so don't ask me questions about it. [Laughter] JULIE: But yeah, we have several big web frameworks now. There are still some probably big holes in the Haskell ecosystem in terms of what people want to see. So, that's one thing that people complain about Haskell for, is that we don't have some of the libraries they'd like to see. I'd like to see something… I would really like to see in Haskell something along the lines of like NLTK from Python. CHARLES: What is that? JULIE: Natural language toolkit. CHARLES: Oh, okay. JULIE: So yeah, Python has this… CHARLES: Yeah, Python's got all the nice science things. JULIE: They really do. And Haskell has some natural language processing libraries available but nothing along the lines of, nothing as big or easy to use and stuff as NLTK yet. So, I'd really like to see that hole get filled a little bit better. And you know… CHARLES: Well, there you go. If anyone out there is seeking fame and fortune in the Haskell community. JULIE: That's actually why I started learning Python, was just so that I could figure out NLTK well enough to start writing it in Haskell. [Laughter] JULIE: So, that's sort of my ambitious long-term project. We'll see how that goes. [Laughs] CHARLES: Nice. Before we wrap up, is there anything going on, coming up, that you want to give a shoutout to or mention or just anything exciting in general? JULIE: Yeah, so on March 30th I'm going to be giving a talk at lambda-squared which is going to be in Knoxville and is a new conference. I think it's just a single-day conference and I'm going to be giving a talk about functors. So, I'm going to try to get through all the exciting varieties of functors in a 50-minute talk. CHARLES: Ooh. JULIE: So, we'll see how that goes. Yeah. And I am still working with Chris Martin on ‘The Joy of Haskell' which should be finished this year, sometime. I'm not going to… [Laughter] JULIE: Give any more specific deadline than that. And in the process of writing Joy of Haskell, I was telling him about some things that, some things that I think are really difficult. Like in my experience, teaching Haskell some places where I find people have the biggest stumbling blocks. And I said, “What if we could do a beginner video course where instead of throwing all of these things at people at once, we separated them out?” And so, you can just worry about this set of stumbling blocks at one time and then later we can talk about this set of stumbling blocks. And so, we're doing… we're going to start a video course, a beginner Haskell video course. I think we'll be starting later this month. So, I'm pretty excited… CHARLES: Nice. JULIE: About that. Yeah. CHARLES: Yeah, I know a lot of people learn really, really well from videos. There's just some… JULIE: Yeah. [Inaudible] for me, so I'm a little nervous. But [Laughs] CHARLES: Yeah, especially if you can do… are you going to be doing live coding examples? Building out things with folks? JULIE: Yeah. CHARLES: Yeah. Well, you just needn't look no further than the popular things like RailsCasts and some of the… yeah, there's just so many good video content out there. Yeah, we'll definitely be looking for the. JULIE: Cool. CHARLIE: Alright. Well, thank you so much, Julie, for coming on. JULIE: Well, thank you for having me on. Sorry I went down some… I went kind of down some rabbit holes. Sorry about that. [Laughs] CHARLES: You know what? You go down the rabbit holes, we spend time walking around the rabbit holes. JULIE: [Laughs] CHARLES: There's something for everybody. So… [Laughter] CHARLES: And ultimately we're strolling through the meadow. So, it's all good. JULIE: [Laughs] Yeah. CHARLES: Thank you too, Elrick. JULIE: It was nice talking to you guys again. CHARLES: Yeah. ELRICK: Yeah, thank you. CHARLES: If folks want to follow up with you or reach out to you, what's the best way to get in contact with you? JULIE: I'm @argumatronic on Twitter and my blog is argumatronic.com which has an email address and some other contact information for me. So, I'd love to hear questions, comments. [Laughs] Yeah. I always [inaudible]. CHARLES: Alright, fantastic. JULIE: To talk to new people. CHARLES: Alright. And if you want to get in touch with us, we are @TheFrontside on Twitter. Or you can just drop us an email at contact@frontside.io. Thanks everybody for listening. And we will see you all later.

Julie Moronuki: @argumatronic | argumatronic.com Show Notes: 00:57 - Julie's Unique Origin Story Into Programming 03:47 - Good Resources vs Bad Resources for Learning Haskell 11:18 - Areas to Look at Before Taking on Haskell and Functional Programming 15:56 - Terminology 17:50 - The Haskell Pyramid 25:51 - Learning Haskell Vocabulary 28:20 - Monoid and Functor 42:06 - Advice for Someone Who May Not Be Interested in Programming Resources: Haskell Programming From First Principles (Haskell Book) Natural Language Processing (NLP) Learn You a Haskell for Great Good! Programming in Haskell by Graham Hutton Haskell: The Craft of Functional Programming by Simon Thompson Real World Haskell by Bryan O'Sullivan, John Goerzen, and Don Stewart Introduction to Functional Programming Course with Eric Meijer The Joy of Haskell Haskell eXchange 2017 - A Monoid For All Seasons Transcript: CHARLES: Hello everybody and welcome to The Frontside Podcast, Episode 83. My name is Charles Lowell, a developer here at the Frontside and your podcast host-in-training. With me today on the podcast is Elrick also. Hello Elrick. ELRICK: Hello. How you doing? CHARLES: I'm doing well. I'm glad to have you on this one. I'm glad to be doing this podcast in general. We have someone on the podcast today who I've been following for, I guess probably about two years because she published a book that has been very, very helpful to me. It's one that I recommend to a lot of people. It is learning Haskell from first principles. With us on the show is Julie Moronuki, who is co-author of that book. Thank you so much, Julie for coming. JULIE: Yes, hi! Happy to be here. It's nice to finally get to talk to you. CHARLES: Yeah. One of the reasons I wanted to have you on the podcast was because I feel as though you have one of the most unique origin stories because of programming and entering in the tech world. Most of us are curious, we either come from video games or maybe we just start fiddling with the web browser. You enter the maze from the entrance that is like hidden from all, I would say. You went straight to writing a book on Haskell, is that --? JULIE: That is what happened. In 2014 on Twitter, I met my co-author, Chris Allen and he has been trying to figure out better ways to teach people Haskell because the on-ramping, I guess of people to Haskell can be quite difficult. The materials that exist are not always accessible and people felt like they need the advanced math degrees before they can write Haskell. He was trying to figure out better ways to introduce people to it. Since I was this person who's never programmed before -- I have no background -- and then he thought, "This will be a very different experience, trying to teach Haskell to her." Because I have a linguistics background and stuff he thought, "That would be interesting too and maybe, she'd be interested eventually in doing NLP." I said, I'm not -- CHARLES: What's that? Acronym alert. JULIE: Oh, yeah. Sorry. Natural Language Processing. I said, "You know, I've never done any programming and I don't play video games and I never have had any desire to learn computer programming. I don't think I'm going to like this. I don't think this is going to last but sure, I will try," and so I did a little bit. I read a little bit of 'Learn You a Haskell for Great Good.' I've read some other things. CHARLES: This was before you guys had the idea of actually writing a book. JULIE: Yes. He had the idea of turning some of his thoughts about teaching Haskell into a book and as he would explain things to me, like the questions I had about 'Learn You a Haskell,' I'd be like, "We should write this down," and he would say, "It's so hard to write it though. It's easy when I'm explaining it to you and it's so hard to write it." Initially, it started that I was helping him at things that he was teaching me and then as we got further into the book and I started reading a lot of other Haskell stuff on my own and figuring stuff out, I was writing more and more of it. Then we were kind of equal co-authors after not too long. That's how it happened. I really didn't think that I would stick with Haskell or with programming. I'm still sometimes I'm not sure about programming. I'm not sure about this whole making software thing. But Haskell is so interesting to me that I'm still here. CHARLES: That is fantastic and it's a great story. I'm curious, when you were doing the proto-research to learning Haskell, coming from really truly first principles and having no experience of programming, what made a good resource versus a bad resource? What are the things that you gravitated towards and say, "This is really instructive." What was the tone there? JULIE: One of the major problems ahead of most of the Haskell resources that exist is they assume that you've done programming before because nobody learns Haskell as a first language so they all assume that you have done some programming before. They would make references to things that if you were a programmer, you would know what they meant but I didn't. That was one of the hardest things for me. Even 'Learn You a Haskell' does that to some extent. CHARLES: What's an example of that? JULIE: I had learned a little bit about recursion from linguistics because that's a thing in human language so I really understood recursion but most of the Haskell resources explain it to you primarily in terms of, "This will be like your loops in other languages." I'm going to be like, "I don't know what a loop is. This isn't helpful for me." There are a lot of things that I didn't understand so when people talk about Haskell as being a pure functional language, neither pure nor functional necessarily, I didn't have anything to contrast them with so they didn't necessarily make sense to me as things that make Haskell different from other languages. I didn't know what imperative programming was and people would say, "In contrast to imperative programming, functional programming does this," and I'd be like, "Okay, but I don't understand what the imperative programming way is so this contrast isn't making any sense to me and same thing with purity." There were a lot of things I had to learn, in fact about mutable state because I didn't know anything about it. I had some understanding of how computer memory works but still some of the ways that people talk about it were not obvious to me. CHARLES: Do you find that seeking out that contrast actually wasn't helpful? Is it noise since at least at the beginning, it's something you'll never do. It's like saying, "Over in France, they wear these kind of socks." Since I'm going out into the street in front of my house, I don't really care. JULIE: Right. In the beginning, it was a lot of noise and I understand why they do that because they are making the assumption that everybody who is learning Haskell has come from some other programming language, probably an imperative one so I understand why that happens but in the beginning, it was very much noise for me. I noticed a lot of Haskell resources, one of the first things they tell you is that in Haskell you can't do 'x = x + 1'. I was like, "If I'm reading this like it's mathematics, why would I think I could do that." If you come from a different programming language, you might well think that you can do that but in Haskell, we can't so making that contrast, when I didn't have that background was really just confusing for me. Now, because I teach people and most of them do have some background in an imperative language, understanding the contrast is more helpful to me but in the beginning it was just confusing and noise. When we wrote Haskell book, we tried not to make those kinds of references and like, "Let's assume that everybody is just like Julie, doesn't know a different programming language that we can contrast it with and let's try to write a book like that." CHARLES: Right. I think that's a key insight because some people would say there's a lot missing or that difference might stand out. Now, that you pointed out, I can see it but I don't think I noticed it while I was reading it. But one of the things that I like is because I also tried to learn Haskell through 'Learn You a Haskell,' and I didn't find it very helpful. I found it entertaining and it's not a knock against the authors. Some of the sketches were really cute but it was still more explaining... I don't know. It was explaining more of the how, than the why, if that makes any sense where I felt as though in your book, there were a lot more analogies to actual human experiences, using the visceral language saying, "A mono is something you can mash together or squeezed together." That really connected for me. Whereas, explaining it in terms of concatenation and laws and stuff like that. Those things seem cited to the secondary resources to the primary resource. JULIE: Yeah. I think that's kind of helpful for me too. There are different Haskell books that have, I think different things about them that are good. I forget the name of the book but Graham Hutton's book, the way he talks about recursion was really helpful to me. The way he explains recursion and of course, folds but folds are things that he's known for so those parts of that book are helpful for me. But really the best book other than my own of course, for me is Simon Thompson's. I think it's called ‘The Craft of Functional Programming' and I think it does better at explaining things just in terms of Haskell. Real World Haskell, I guess is really good. It was harder for me because I hadn't been a programmer before. I think it's got so many practical exercises that -- CHARLES: Was that the O'Reilly book by Irish gentleman whose name eludes me? JULIE: Yes, Brian O'Sullivan. It makes more sense to me now but there were things in it that are sort of programmer things. Because I'd never made software before, that were really confusing for me. But Simon Thompson's, because his book does have exercises and they were ones that I could understand and do. They were fairly self-contained. My first experience actually in writing a program that does IO was from his book and I was just so thrilled. I was like, "I got it. I did it." That was really helpful book for me but I don't see people recommend that one as often but that was probably the best one for me. CHARLES: Yeah, it's always a balance because the Real World Haskell didn't really worked for me, almost because the examples were too pragmatic or too complex and I picked this up when I was 10 years into my programming career and I struggled to follow the JSON parser example, which is parsing JSON is something that I've actually done several times in multiple languages and I still struggled with it. JULIE: Whereas for me, I don't even know what JSON is. This is not something I've ever dealt with. I know what it is now sort of, but it's still not something that I deal with very much. I was just like, "What is this? I don't even know what to do here." It wasn't quite as helpful for me. I've heard a lot of people have success with that one but I think they don't share quite the same richness of programming experience with Brian O'Sullivan. I think it's a little bit more difficult. ELRICK: These are a lot of amazing resources that I wish I knew about when I try to learn Haskell. I took an online course with, I think it's like Eric Meijer and that class was very intense. Looking back, what would you say are some areas that someone should, either start to look into before they step into the Haskell world, being that you didn't come from a programming background but connecting to dots backwards now? What would you say are some areas that people can slowly ramp up into to get into Haskell and functional programming? JULIE: When I teach people Haskell, the people who have the easiest time are people who have been writing Scala for a while and they've moved over to the FP in Scala side. When I first started Haskell, I heard a lot of people make jokes about how Scala is a gateway drug to Haskell. I think there's actually might be so truth in that because I certainly have a lot of students that were Java programmers, then they got interested in Scala because maybe Scala is better for some things than Java and then they start moving more and more over to the FP in Scala side. Those are probably the students that have, I think the easiest time making the transition to Haskell that I've had anyway. But you know, I think even JavaScript, trying to write in a more functional style and there are some resources for that and really, there's a very good tutorial about monads that uses all the code examples in JavaScript. I think a lot of the concepts that you can start to approach them from other languages. Haskell is still going to be weird in a lot of ways and another thing that works for a lot of people is going to Elm. Elm is similar to Haskell but different. I think that that has worked also for a lot of people getting them into understanding more functional programming concepts but with the much easier... The word easy is so -- ELRICK: It's like a relative term like, "Oh, this is easy." JULIE: It is. CHARLES: Easy to say, right. ELRICK: That's what I thought when I step into learning Haskell and functional programming. I was like, "How bad could it be?" JULIE: Right. Learning Haskell can be very bad. I'm not going to kid around about that. It's a shame because I don't think that it needs to be that bad but the way it's presented oftentimes, for various reasons, I think why Haskell gets presented the way it does but I don't think it needs to have it like that. The designer of Elm, whose name I'm not going to try to pronounce because I don't know how you say his last name, he really made an effort to for example, the error messages in Haskell can be very intimidating. The situation there has improved since I started learning Haskell but they can be quite intimidating and he really made an effort to make very friendly error messages, very helpful error messages. I think that it shows and then it makes a difference for people who are learning. If you start with Elm and then you do want to see what Haskell or PureScript, which is also frontend language, mostly. It compose of JavaScript but it's very Haskell-like, then from Elm, let's see if we can get a little more hardcore Haskell. I think the transition to Haskell or PureScript is easier from there. I think it does help to move in the functional direction from whatever language you're in, if you do FP in Scala or try moving to more functional JavaScript or even Elm. Then Haskell will make it more sense from there or be a little easier to approach. CHARLES: Yeah, and I definitely think that for, at least from my perspective, I've been able to take a lot of those concepts that I've learned from Haskell and then apply them, even inside Vanilla JavaScript. There are things that have become indispensable like mapping and folding and they exist in JavaScript. You can reduce arrays, which is a similar to a fold and then you can map arrays but understanding that map, the key insight for me that I got from learning Haskell is that there's a whole class of values that you can map, not just arrays. The standard JavaScript object is essentially a Functor and will get a little bit to that because for people listening what that word even means and the meta around the fact that they're all these weird words and how do I go about something I want to ask you about. But the trees can be mapped and the objects can be mapped and all of the sudden, it's like this one concept that I use so much for lists, it's available on all these different data structures and it's get me thinking like, "What other data structures can I use this operation? What are the things are Functors that I'm working with?" Really, it's changed my perspective to think about the type of the data structure, in terms of the operations. JULIE: I'm in favor of keeping the terminology that we have but just explaining it much better. That's the approach that I take but it can be very hard, especially it was your first learning Haskell. I don't know if you've seen the Haskell pyramid but to get sort of productive where you can write programs in Haskell is not a very high bar. It feels like it is when you first start but it's not really very high bar but Haskell just keeps growing and growing and getting deeper and deeper so you're always approaching new libraries that you've never seen before and you feel then you've been learning Haskell all over again because they're written in a very different style of Haskell or they have even more terminology, even more kinds of Functors that you've never heard of before or something like that so you're always approaching these things over again. It can be a very intimidating feeling and it makes a lot of people very uncomfortable and I'd say, if you like Haskell and that does make you feel uncomfortable, then you don't actually need to do that because a lot of people write Haskell very happily every day in their jobs even and don't do that. They don't mess with some of the newer, super cool libraries that have all this funky terminology and stuff. Some of them don't mess with them at all. CHARLES: But certainly, there is some concepts that are core. I'm thinking of like applicative and Functor and all these things that I'm learning about and I'm curious to hear about your experience as you climb that pyramid. What is the pyramid entailed? First of all, I'd love to hear more about it because this is actually the first time I heard about the Haskell pyramid. JULIE: Say you understand monads, then you can write really a lot of Haskell programs. Probably at some point, you will need to understand monads transformers but if you just get to the point where you understand monads pretty decently, you can write a lot of software so after that, then learning more is maybe going to improve your Haskell, maybe let you write some things that you couldn't write before but a lot of it above, not that these things are necessarily in an hierarchical progression. We cover monad transformers in a fair bit of detail in Haskell book but if you get anything beyond what's in Haskell book, one of those things that some of them are very interesting, some of them can make you much more productive but some of them are also people do them for fun to explore the space and some people love them and some people hate them. Haskell lets you do a lot of things for fun and exploring mathematics in ways that are interesting and exciting and may influence and in fact, have influenced other languages like [inaudible] in PureScript but not really necessary for basic Haskell programming. A nice thing happened while we're writing Haskell book. I was writing, I think it's chapter six, which is about type classes. I was writing that chapter and at the same time, my co-author had started writing the Monoid chapter. The type classes chapter comes in chapter six and we introduce a lot of the basic type classes: num and eq and some of those in that chapter because I do think it's important. Type classes are very special thing about Haskell so I think it's important to, at least start coming to groups at them early. Some people disagree with me about that and think they can ignore them for much longer. But at any rate, it is where it is and I felt that that was important. Maybe the real motivation for type classes, really until we started writing the Monoid chapter so he started writing that while I was working on type classes chapter and he sent me the beginnings of the Monoid chapter to look at. At first I thought, "We've got addition and multiplication and list concatenation and this just doesn't seem interesting. What is this generalization of a Monoid that I'm supposed to get from these three things? And why bother making it a type class," because additional and multiplication are already in the num type class and then list concatenation is just for list so why make this into a type class and what's that motivation there. With eq, we want a quality -- CHARLES: Is that how you pronounce 'eq?' JULIE: That's how I pronounce it because 'equal' or equality. CHARLES: Okay, so this is a type class for doing what? Making sure to being able to compare two values on the same value. JULIE: Yes and it's a weird one because for most data types, you can have an eq instance and you want probably, in a lot of cases to have that but we don't want because function is a data type in Haskell so you don't want to have an eq instance for functions and that's why equality is not implemented generally for everything. That's why it's a type class so there's no instance for functions because that's not decidable. You can't decide if two functions are equal, generally. Some functions you can but in the general terms, for datatype, you can't. CHARLES: That's actually a pretty profound statement. Proof of which is left as an exercise for the listener. JULIE: We got to the Monoid and I was like, "What is the [inaudible]," or something. It turns out that there are Monoids everywhere. There's all kinds of things that you want to, either concatenate or make a product of. Then having this as a type class and thinking of it in terms of like, "We've got this abstraction. We've got this category. We've got this algebraic structure. Now, we can look for in all these other places," because once you've named the thing, then you can talk about it and think about it in a little bit of the different way. It's like, "Now, we've got this group of addition, multiplication, list concatenation." Now, we've got an abstraction of that and we can think, "Where else can I see this pattern?" and it turns out it's all over the place. For me, that was one of our thought like, "Type classes are actually really cool and powerful and interesting thing." For me, that was when it seemed like, "The terminology is worth it because, now I want to think about finding these algebraic structures and in all these other places." CHARLES: Right and like a Monoid, it could essentially be called, if you're using a Java interface, like 'mashable togetherable' or 'concatenatable' or something like that. But there's a kind of one-to-one correspondence but it is a vocabulary that just needs to be learned. JULIE: I don't know much about category theory or anything but the other cool thing about Monoid for me was that there are almost always two because there's almost always one that's destructive or additive or concatenative and there's almost always one that is conjunctive or a product or multiplicative. It's often across product that would be the zipless Monoid that exist in base and it's a cross product of the two lists. There's almost always two, whereas when you think of Monoids in the very abstract looking category theory, it doesn't matter if it's addition or multiplication. The operation doesn't matter, whether it's addition or multiplication or concatenation or cross product because you generalize the actual operation to the extent where what it's going to produce. It doesn't matter anymore. For me, I still think of Monoids in terms of like set theory or Boolean Algebra, then that's one of the things that I think is difficult with Haskell where people talk about Monoids in terms of category theory but I think that's not very helpful for the actual programmer who has to actually deal with the two different instances like sum and products or concatenation and zipping are going to actually act different in a program. CHARLES: Right, they're going to yield a different set of values. JULIE: Yes. CHARLES: Is there a baseline vocabulary? I kind of think of it like learning a new language, right? JULIE: Yep. CHARLES: When you're learning Haskell, you're not just learning a new language. You're literally learning a new language. I could go and I could learn Japanese but it's going to be a struggle at some point. People say certain languages are hard and certain language are easy. I don't generally subscribe to that. I think that most of it is just going about and living in a place where they speak this language and you'll absorb it and it's the decision to go and live there -- that's kind of the primary one. But let's say, you're a foreigner and you're travelling to this country called Haskell that's got this strange language. Like other human languages, it's just got different names associated with different concepts and some of the concepts might even just be unique to that country. Just like when you're travelling and acquiring a human language, there's a certain level of vocabulary that you need to achieve before you can do things like buy groceries and be able to transact financial exchanges or have a conversation about the weather. What are the kind of the levels of vocabulary that you need to acquire to be operational in Haskell or I would say, even in functional programming because now that I've been exposed to this, I see it in Clojure. I actually see people doing this JavaScript and in Erlang, in Elixir and what have you. JULIE: Yeah, I don't really know how to answer this question. How to buy groceries in Haskell? CHARLES: Let me let scale that down because I had this horrible tendency to spend five minutes asking what I say is going to be single question but it's actually like 30. Let's take down the scope. When you were learning this vocabulary, at what point did you feel like you're really gaining traction? We're you really starting to connect the dots? JULIE: For me, I think when I got through Functor. It was when I felt like -- CHARLES: Functor and what comes before Functor? JULIE: Monoid. I think once you understand Monoid and Functor, then a lot of other concepts in Haskell will start falling into place because this is not obvious to everyone but I think once you really understand Monoid and once you really understand Functor, then applicatives are monoidal Functors and that's not obvious to everyone. Like I said, it's not obvious at first certainly, and monads have characteristics of both Monoid and Functor as well. Then you start saying, "There's all these other Functors. There's profunctors and bifunctors. I think once you really understand Monoid and Functor, a lot of the rest of Haskell starts falling into place and then type classes like alternative. Alternative is another kind of Monoid. We have all these other names that if you can see the general pattern of Monoids and Functors, I think to me anyway, a lot of it then just started falling into place. Applicatives to me seemed, I don't want to say obvious or simple but in traverse, it's same sort of thing so we have these other names for it -- traversable -- and I was like, "Why was it called traverse. I don't understand this word at all." But once I saw the type signature and what actually happens with what the function traverse does, I was like, "Okay, I see what's happening here." For me, those were the two big hills. Once I got through Monoid and Functor and really understood them well, then a lot of other stuff just come and fell into place for me. ELRICK: This is really interesting. How was a Monoid explained to you when you were first starting to learn Haskell? Then now, how do you explain what a Monoid is to someone that's learning Haskell? JULIE: When Monoid was first explained to me, it was the pattern of there's addition and multiplication and list concatenation so it generalize out that pattern and that was really hard for me to understand at first because list concatenation and addition are similar but multiplication is different. I was like, "What do these three things have in common?" What they have in common is that they take two values of a certain type and return another value of that type and that's the type signature of the main function, that's in the Monoid type class. But that doesn't really tell you very much. A lot of functions could do that, in theory at least. How you combine them is really what's interesting about Monoid and also what makes concatenation and addition different from multiplication. Fortunately in college, I had had a fair bit of exposure to Boolean Algebra so figuring out that like, "There's actually two basic genres or varieties of Monoid and they are disjunctive or additive or they are conjunctive or multiplicative," and figuring that out, to me I always think that Monoid should really be, maybe two different type classes, one for the additive Monoid like list concatenation and addition and things where you are adding two things like a set union. Then conjunctive, which would be this intersections or multiplication or cross products. I always think there's maybe should be two different type classes but there's not a good way to do that really in Haskell. Instead, we have this one type class and then we do this ugly business of wrapping them in different type names. CHARLES: Is that why you'll have a constructor for some so it's just a wrapper for an integer? JULIE: Yeah. CHARLES: I don't know if that's so bad. JULIE: I don't like it but -- CHARLES: Yeah. You know what? You do a lot more than I do so I'm going to take your word for it. JULIE: Yeah, that's exactly why. Sum and product are the wrappers for integers because integer doesn't have a Monoid. It has two Monoids over it. CHARLES: I see. There's lots of ways to combine integers. JULIE: Yeah and those are the two basic ones. Then because Monoids also have an identity so with semi-groups, then you get even more semi-groups for integers because you get max and min, because they don't have an identity so there's semi-groups. CHARLES: There's always risk getting down into the weeds with the vocabulary but I think that there's a message here because your answer to the question is really, "When I understood Monoid and I understood Functor," from that point on, the overhead that you had to expend to get other things was lower than the overhead that you had to expend to get those initial two things. For anyone listening, Monoid and Functor are probably opaque terms. You have no idea what the hell they mean. We've been talking about in things like that a little bit but then it's okay because they're a finite set of opaque terms and they're very achievable and once you can achieve those, then you've done 90% of the work and now, you're just combining them into interesting and novel ways. JULIE: Yes. I will say it that a lot of people do tell us about Haskell book that applicative is actually the hardest chapter in the book, not monad but applicative. CHARLES: Really? JULIE: Yeah. A lot of people do tell us that. Because that's the first time that you've taken the concept of Monoid and the concept of Functor and combining them into a new thing so then, once you've done that with applicative, then after that, really it's all downhill. CHARLES: Right. It seems like there's a couple of key insights. As you're climbing that hill, I like that analogy is like one, just understanding that there things like type classes so you've through attacking Monoid and through attacking Functor, you realize, "There is such a thing." By recognizing there is such a thing as a Functor, you recognize that there is the potential for other type classes like it. Then through combining it with Monoid, to get applicative, you can see, "I can actually compose these things into new instances of those things," and then that's either the crest of the hill or the Pandora's box, depending on which way you look at it. I think there's a hopeful message in there that if you can invest the time to learn these opaque terms and making them transparent to you, you can really, really, really lean heavily on that knowledge in going forward. JULIE: Yeah. I'm writing a new book now called 'The Joy of Haskell.' The idea of The Joy of Haskell is meant to be an intermediate book. For people who already know some Haskell but we want to make words like Functor more general, like in Haskell book we really focused on the type class called Functor when it's actually a concept from mathematics or actually originally from linguistics oddly enough but we really focused on the type class in there, rather than trying to explain what a Functors are generally. In the new book, in The Joy of Haskell, we're going to try to take a lot of these terms like Monoids and Functors and catamorphisms and all these other words that Haskell has used all the time and try to explain them generally. Then also give examples like interesting uses from different libraries and stuff like that. It'll service both, hopefully a guide to the vocabulary of the Haskell ecosystem and also some documentation and examples for libraries and things like that that are useful because these things do have uses. They do get used in interesting and exciting or terrifying -- maybe those are related -- ways. That's the goal of the new book is to try to make a guide to all of this vocabulary that Haskell use all the time. We're trying to do that. How do I explain Monoids, you asked. You've got two values of whatever type. It doesn't matter the type and in general, there would be two ways you can think of to combine them, either making a sum or a union of all the values in them or making some product of those values, if they contain multiple values or even if they only contain one. That's how I explain them now. I'm not certain that addition and multiplication are actually the best ways to start with that because addition and multiplication don't act quite like set union and intersection do. I'm actually thinking of them in terms of and this is how I explain monoids to the people now, I start from set theory and that sounds really heavy but it doesn't have to be because I think a lot of things about sets are -- CHARLES: They're very intuitive, especially if you have visuals. JULIE: They're very intuitive, for people to think about. Yes, exactly. I explain Monoid now more in terms of set union and intersection. I'm actually giving a talk in October. It's coming up in just a couple weeks at Haskell eXchange in October 12th and 13th in London and I'm giving a talk there called 'A Monoid For All Seasons' and I'm going to try to explain the theoretic motivation for Monoids and try to explain them in those terms. Semi-group is a little bit different because lacks the identity but I'll try to explain the alternative type class and monad plus this really the same thing as alternative. These things are also just Monoids so we have these different names because it's a different type class alternative but it's really just another kind of Monoid. I'm giving that talk about set theory in Monoids in October, in a couple of weeks. People keep asking me on Twitter, "What's your obsession with Monoids," because my name on Twitter is Monoid Mary so I try to explain why I love them so much. CHARLES: Actually, it's an awesome point, which I've just gotten to experience it is what you see like, "Oh, there are these abstract things," you start searching for them. A lot of times, you'll uncover them and it'd be a real timesaver. There's the thrill of unearthing it in the first place and then when you could say, "Now that I've identified this thing as a Monoid, there's so much less that I have to write." There's like less work that I have to do. It's the same reason that we write frameworks for ourselves in software. It's like, "We love Ruby on Rails because of all the work we don't have to do." Now, you have to expend a lot of energy to work with it, using Rails an example but there's lots of software frameworks. It's like, "If you can find a good persistence framework or you can find a good thing for making a library for handling HTTP requests and responses, why would you write it all by hand in the first place?" I think the thing that's exciting for me as a developer is being able to see, "Monoid is a thing. Functor is a thing and I can now actually use this and I can use it almost as a looking glass to explore the world around me. When I see something in the landscape that just leaps out through that lens is another great one." I've been on a big kick lately but being able to say, "This is going to save me so much time because of the thoughts that I don't have to think and the code that I don't have to write." I think connecting it back to the pragmatic, I certainly have become really obsessed, maybe not about Monoids but having a type class large in your mind. JULIE: I think it's a really powerful thing. Sometimes that jargon is really useful. It's useful in a sense that it like compresses a bunch of information into a single word to remember. It's like teaching my eight-year old multiplication and we were talking about like, "It's like addition," and for us adult, I'll just go ahead say, "It's associative and commutative," but showing him that you can do those things and that addition is like that too and we're talking about that and he was so excited to learn that there's this word 'commutative' that encapsulates this idea for both concepts so he doesn't have to think like, "Addition does this thing. Multiplication does this thing." He doesn't have to remember both of those things, like he just remembers, "Commutative and they're both like this." It kind of compresses that information and what you have to remember and think about. Then it does make it easier to see that pattern in other things, then we can find commutativity in other things because now we have this pattern that we can look for and we got a name for it. We can talk about it and really, there's a lot of stuff like that in Haskell where we find some pattern that we find useful or we want to be able to talk about or easily translate to a bunch of different types, not translate is quite the right word but you know what I mean, I think. Then we give it a name and we make type class for it and then it's, "Now, we find it even more place for us." CHARLES: Right. It's about thinking less, right? JULIE: Yeah. CHARLES: That's a big misconception is that it's not about thinking more, it's about thinking less. JULIE: It really is. I think it's because there's so much kind of upfront work, where you have to learn all this new stuff upfront, then people mistake that for how much work we're always doing but in Haskell it's like, "We did all this work upfront and now we're now we're not going to think about these things anymore." ELRICK: That sounds like a good title for a book, 'Learn Haskell and you will think less," but it's true. When I struggled through that online class, I came out of that just being able to pick up any functional programming language and just hit the ground running. It is definitely a plus and you will think less. JULIE: Yeah, in the long term, I think that you do. Haskell is not a perfect language. There are things that probably can be improved. CHARLES: Now, before we go, I wanted to ask you, having had this very unique on-ramp into programming, which apparently you're still not convinced about. I'm curious what it would take to actually convince you but the real question that I have is there any advice that you have for someone who does not have a stereotypical background in programming who may not think that they would find programming interesting, who might have any number of roadblocks in terms of their own conceptions about the path forward. What advice would you have for them? JULIE: I am a bit joking when I say that I'm still not sure about writing software. I don't feel like I'm good at it and I think this is really the key. There are a bunch of domains in programming that I don't personally care about. I don't want to make web apps and I have nothing but respect and admiration for people who do. To me, it's very, very hard. CHARLES: Mostly because our tools aren't the same. JULIE: Yeah and there's just so many things outside your own program, there are just so many things that you have to think about and deal with because there's the network and there's other people's computers and they might be doing in other people software and what it might be doing. It is insane so for me it's very hard. There's a lot of domains of programming that I don't care about and when I thought about programming, that's the kind of thing I would think about. I certainly knew a lot of people who are web developers or the common programming jobs, I guess. Some of them just weren't that appealing to me and I'm not interested in making games or graphics so those are the kinds of things that I thought about for programming. There are things though that I am interested in doing. I'm very interested in natural language processing and I guess that's related to machine learning. I've recently taken up an interest in things like the raft protocol, the consensus protocol. Those kinds of things interest me a lot and there's a lot of the theory that interests me. I'm reading a dissertation right now about implementing a non-strict lambda calculus, which is what Haskell is. It's a non-strict lambda calculus and this guy's dissertations are theoretically implementing a non-strict lambda calculus. To me, the theoretical side is really interesting but then I am also interested in certain kinds of software. For some reason, I have developed quite an interest in making Twitter bots. I think that the advice I would give -- I'm rambling a little bit -- to people who think they're not interested in programming so why should they learn or whatever, is just find the thing that you are interested in and there's probably a way you can make software for that and maybe that will be the thing that will get you interested. It might not be Haskell, maybe you are interested in making web apps, in which case I would say go for Elm or PureScript, obviously because I like functional programs but Haskell might not be the best first language for you in that case but find the thing that you're interested in and there probably is a way to write software to do that. There's probably something in programming that will interest you. It's such a vast field. CHARLES: All right. I really, really like that answer. ELRICK: Yeah, that's a beautiful advice. Find your domain. CHARLES: Yeah, it's bigger than you think. JULIE: It's much bigger than you think. CHARLES: And there is a place for you. Thank you so much for coming on the show, Julie. I really, really, really enjoyed our conversation. JULIE: Yes, so did I. This is a lot of fun. CHARLES: Thank you. Now, before we go, I understand that you are going to be in London, was it roughly very, very soon, you said you were giving a talk. JULIE: Yes, the 12th and 13th of October. It will be recorded for people who can't get in. It will be recorded, I believe. CHARLES: You will be talking on 'A Monoid For All Seasons.' JULIE: Yes. CHARLES: And then you've also got The Joy of Haskell book, which you're hacking away right now, right? JULIE: Yes. CHARLES: With that, thank you so much for both of you. Thank you all for listening. What's a good place for people to reach out for you? JULIE: If they're on Twitter, I'm very active on Twitter so I'm @argumatronic on Twitter and my blog is also Argumatronic and that has more contact information. CHARLES: Fantastic. We'll link to those in the show notes. For everybody else, thank you for listening. You can get in contact with us at @TheFrontside on Twitter and Contact@Frontside.io over email. We'd love to hear from you. This just in, we're running a special. If you go to our website and enter the promo code 'ELRICK20,' you can get that 20% discount on your next custom developed web application. Go check that out. Take it easy, everybody. Bye-bye. JULIE: Bye-bye.

Into the icy maw of category theory starting with Monoids! In reality we find out it's not actually all that scary and there are some really fantastic things that we gain by understanding these basic categorical concepts. We now have a twitter account! Follow us at https://twitter.com/lambdacast We also now have a patron account if you're looking to support the show: https://www.patreon.com/lambdacast Show Notes: Haskell Diagrams library http://projects.haskell.org/diagrams/doc/quickstart.html https://vimeo.com/84104226 Chris Wilson pointed out that Haskell's Typeclassopedia has a nice chart of the relationship between Haskell's implementation of many categorical structures: https://wiki.haskell.org/wikiupload/d/df/Typeclassopedia-diagram.png

Chris Penner Hanabi Skyladder Mindfulness meditation Primitive Obsession POJOBoolean BlindnessDestroy All IfsMuniHac 2016: Beautiful folds are practical, toopurescript-halogenIntegrating PureScript and Halogen into JavaScript ApplicationsThe J Programming LanguageNumeronymAs-patternsComonads, Monoids and Trees

The Monoids have taken over but we are still broadcasting. Enjoy a brand new episode of Bad Wolf Radio. The Tenth is travelling again. We talk about David Tennant hitting the US convention scene and how much we'd pay to meet him. Listener feedback. We got a couple more messages and we read them on the show. Five minutes of Danny Pink. New Titan vinyls are coming in August and we talk about which ones we'd buy and where we'd place poor Danny. Also Adam thinks we need to change our intro. Which episode of Doctor Who has had the most formal complaints filed about it? Adam let's us know. More Ninth Doctor! A new comic series is coming from Titan in April. What happened to Vicki? Before we talk about our Classic Who adventure we do a quick recap of what happened in all the episodes that we missed. 700 years is a long time. We discuss the Classic Doctor Who adventure "The Ark."

The Three Who Rule are slightly in tatters this week with Warren away in the Deep South and Chris fighting a cold that would easily fell the entire population of a space ark that left Earth in the 57th Segment of Time, Monoids included! Fortunately, all is quiet on the news front again this week as the world of Doctor Who is focused internally on actually making new episodes for broadcast in the fall. As a result, we turn to the past again as Steven, Warren, and Chris commentate over the final three episodes of the 1971 serial The Mind of Evil, featuring The Master, rockets, epic gun battles, and some delectable soup. Check out the show notes at http://www.radiofreeskaro.com Follow us on Twitter: @radiofreeskaro

Almost ten million years in the future, the materialises on a vast spacecraft including its own miniature zoo and arboretum. The and are still explaining the basics of their time travel ability to new companion when she starts to show signs of a cold. It is only a matter of time before they are found and taken to the control chamber of the vessel. Their captors are the mute Monoids, seemingly identical alien beings with a single eye. The Monoids live in peace alongside the humans who command the spaceship, their own planet having been destroyed, but often do much of the menial work. The humans in charge of the ship explain that the Earth is about to be destroyed because of the expansion of the sun, and that this ship is an Ark sent into space with the last remnants of humanity, civilization and various forms of flora and fauna. The human Guardians in charge of the craft run a tight ship: failure to conform to rules means either death or miniaturisation until they reach their destination, an Earth-like planet called Refusis II, which takes nearly 700 years to get to. As an amusement during the journey a vast statue is being carved by hand, depicting a human being. Dodo's cold has now spread amongst the Monoid and human populations, but regrettably, they have little natural immunity. When the Commander of the Ark collapses with the malady, the whole ship is placed on alert as Zentos, the Deputy Commander is suspicious of the travellers and believes they have deliberately infected the ship. When the first Monoid dies, there is little the Doctor can say to pacify the angry Guardians. Zentos places the Doctor, Steven and Dodo on trial for their crimes, with a young Guardian called Manyak and the Commander's daughter Mellium as defence. Steven acts as the first defence witness, attacking the closed nature of the minds of the Guardians, but exhausts himself in the process and collapses with the fever. His words have no impact on Zentos, who orders their execution, but the ailing Commander intervenes to protect the three travellers and permit them access to medical equipment to devise a cure to the cold. The Doctor is thus able to recreate the cold vaccine from the membranes of animals on the craft, and this is administered throughout the crew. The Commander, Steven and the others infected are soon on the road to recovery. Their work done, the trio have only time to observe the end of Earth on the long-range scanner before the Doctor leads them back to the TARDIS. Curiously, when the TARDIS rematerialises, they are still on the Ark. However, seven hundred years have passed and there has been a major change: the Monoids are in control. They have completed the statue in the image of themselves, having staged a coup during the long journey. This was made possible by a genetic weakness introduced into the humans, but not the Monoids, by a second wave of the cold virus 700 years earlier. The Monoids also now have voice communicators and use numerical emblems to distinguish each other. The humans are now little more than slaves, with the odd exception like the collaborator subject Guardian Maharis, and have little hope of change. The Doctor and his friends encounter the Monoid leadership, installed in a throne room on the Ark, after which they are sent to the security kitchen to help prepare meals for the Monoids. Two humans, Manissa and Dassuk, believe the moment of their liberation is at hand. Steven tries to help them in a revolt which is unsuccessful. The arrival on Refusis is close at hand and a landing pod is prepared. Monoid 1 wants to make sure that the new world is inhabited only by Monoids, despite promises that the human population will be allowed to live there too. A landing party is assembled – the Doctor, Dodo, Monoid 2 and a subject Guardian named Yendom – and they soon reach Refusis II and start to investigate. A stately castle which seems to be unoccupied is in fact the home to the invisible Refusians, giant beings rendered invisible by solar flares. They welcome their guests and have been expecting them but only want to share the planet with other peaceful beings. Monoid 2 and Yendom flee the castle, and en route Yendom realises the humans will not be allowed to reach Refusis with the Monoids. Monoid 2 kills him and is shortly afterward killed himself when the landing pod explodes. The tension of the situation foments dissent in the Monoid ranks, with Monoid 4 openly opposing Monoid 1's plans to abandon the humans and colonise Refusis without more checks on the planet. Three launchers are sent to the planet, Monoids 1 and 4 commanding them, and when the crews emerge Monoid 4 interprets the destroyed landing pod as evidence of the danger that Monoid 1 has led them to. A civil war erupts between the two Monoid factions. The Doctor, Dodo and a Refusian use the confusion to steal one of the launchers and pilot back to the Ark. The Monoids have placed a bomb on board the ship and plan to evacuate soon to the planet surface, leaving the humans to die on the spaceship. Word of this threat spreads and spurs a human rebellion. The arrival of the Doctor and the Refusian spur things along, and they soon realise the bomb has been placed in the head of the statue. Thankfully the Refusian is able to help dispose of the statue into space before the bomb explodes. The humans now begin to land on Refusis themselves, having been offered support on peaceful terms by the Refusians. Many of the Monoids have been killed in their civil war and those that remain are offered peaceful settlement alongside the other two species. Once more the TARDIS departs, and this time the curiosity is that the Doctor simply vanishes from the TARDIS control room… [] Continuity In , the Earth was also evacuated because of solar flare activity that rendered the biosphere uninhabitable for five thousand years. There, however, the survivors of mankind slept in suspended animation and returned to repopulate the planet after that period had passed. The Earth is seen trailing smoke as it heads towards the Sun at the close of episode two. The Doctor estimate the date as 10,000,000, however in the 2005 episode "", Earth is finally destroyed by the expanding Sun around AD 5,000,000,000. Series writer opines that the fictional alluded to in the revived series of Doctor Who rewrote some historical events, among them the destruction of Earth. The Monoids also feature in the audio drama by . The TARDIS is referenced in the first episode as "that black box" whereas by the time of the third doctor when the series was recorded in color it is obviously a blue police box. [] Production Serial details by episode Episode Broadcast date Run time Viewership (in millions) Archive "The Steel Sky" 5 March 1966 (1966-03-05) 24:00 5.5 16mm t/r "The Plague" 12 March 1966 (1966-03-12) 25:00 6.9 16mm t/r "The Return" 19 March 1966 (1966-03-19) 24:19 6.2 16mm t/r "The Bomb" 26 March 1966 (1966-03-26) 24:37 7.3 16mm t/r Although is credited as a co-writer, she does not appear to have done any actual work on the scripts. Her then-husband, Paul Erickson requested that she be given a credit, but her name appears on no other related documents. Despite this, Scott was credited as a contributor to the s published by /. The Monoids were played by actors, each holding a ball in his mouth to represent the alien's single eye. The upper portion of the actor's face was hidden by a . This serial features a guest appearance by Michael Sheard. (See also .) book The Ark Series Release number 114 Writer Publisher Cover artist ISBN Release date October 1986 (Hardback) 19 March 1987 (Paperback) Preceded by Followed by [] Commercial releases This story was released on , in 1998. It was later released on CD (The CD version contains a two minute reprise from the end of the previous story The Massacre), with linking narration by Peter Purves. The CD also includes an interview with Peter about this story and his time on Doctor Who. This CD is available as an Audio Book on the . It is scheduled to be released on DVD in 2011 and will have an audio commentary with Peter Purves and Michael Imison. [] In print A novelisation of this serial, written by , was published by in October 1986. [] References Shaun Lyon et al. (2007-03-31). . Outpost Gallifrey. Archived from on 2008-03-31. . Retrieved 2008-08-30.  . Doctor Who Reference Guide. . Retrieved 2008-08-30.  Sullivan, Shannon (2005-04-29). . A Brief History of Time Travel. . Retrieved 2008-08-30.  , "Doctor Who Archive: The Ark," , #228, 2 August 1995, , p. 26. Pixley, Andrew, "The Ark: Archive Extra," , #7, 12 May 2004 (The Complete First Doctor), , p. 73.