Strategies for Adhering to Rules in a Dynamically Typed Language

Joël has been pondering another tool for thought from Maggie Appleton: diagramming. What does drawing complex things reveal? Stephanie has updates on how Soup Group went, plus a clarification from last week's episode re: hexagons and tessellation.

They also share the top most impactful articles they read in 2022.

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• Maggie Appleton tools for thought
• Squint test
• Cardinality of types
• Honeycomb hexagon construction
• Coachability
• Strangler Fig Pattern
• Finding time to refactor
• Parse don't validate
• Errors cluster around boundaries

Transcript:

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STEPHANIE: Hello and welcome to another episode of The Bike Shed, a weekly podcast from your friends at thoughtbot that has basically become a two-person book club between me and Joël. [laughter]

JOËL: I love that.

STEPHANIE: I'm so sorry, I had to. I think we've been sharing so many things we've been reading in the past couple of episodes, and I've been loving it. I think it's a lot of the conversations we have off-air too, and now we're just bringing it on on-air. And I am going to lean into it. [laughs]

JOËL: I like it.

STEPHANIE: So, Joël, what's new in your world?

JOËL: So, in a recent episode, I think it was two episodes ago, you shared an article by Maggie Appleton about tools for thought. And I've kind of been going back to that article a few times in the past few weeks. And I feel like I always see something new.

And one tool for thought that Maggie explicitly mentions in the article is diagramming, and that's something that we've used as an industry for a long time to deal with conditional logic is just writing a flow diagram. And I feel like that's such a useful tool sometimes to move away from code and text into visuals and draw your problem rather than write your problem.

It's often useful either when I'm trying to figure out how to structure some of my own code or when I'm reviewing a PR for somebody else, and something just feels not quite right, but I'm not quite sure what I want to say. And so drawing the problem all of a sudden might give me some insights, might help me identify why does something feel off about this code that I can't quite put into words?

STEPHANIE: What does drawing complex things reveal for you? Is there a time where you were able to see something that you hadn't seen before?

JOËL: One thing I think it can make more obvious is the shape of the problem. When we describe a problem in words, sometimes there's a sense of like, okay, there are two main paths through this problem or something. And then when we do our code, we try to make it DRY, and we try all these things. And it's really hard to see the flow of logic. And we might actually have way more paths through our code than are actually needed by the initial problem definition.

I think we talked about this in a past episode as well, structuring a multi-step form or a wizard. And oftentimes, that is structured way more complex than it needs to be. And you can really see that difference when you draw out a flow diagram, the difference between forcing everything down a single linear flow with a bunch of little independent conditions versus branching up front three or four or five ways, however many steps you have. And then, from there, it's just executing code.

STEPHANIE: I have two thoughts here. Firstly, it's very tragic that this is an audio medium only [laughs] and not also a visual one. Because I think we've joked in the past about when we've, you know, talked about complex problems and branching conditionals and stuff like that, like, oh, like, if only we could show a visual representation to our listeners. [laughs] And secondly, now that makes a lot more sense why there are so many whiteboards just hanging out in offices everywhere. [laughs]

JOËL: We should use them more. It's interesting you mentioned the limitations of an audio format that we have. But even just describing the problem in an audio format is different than implementing it in code. So if I were to describe a problem to you that says, oh, we have a multi-step form that has three different steps to it, in that description, you might initially think, oh, that means I want to branch three ways up front, and then each step will need to do some processing. But if you look at the implementation in the code, maybe whoever coded it, and maybe that's yourself, will have done it totally differently with a lot more branching than just three up front because it's a different medium.

STEPHANIE: That's a really good point. I also remember reading something about how you can reason about how many branches a piece of code might have if you just look at the structure of the lines of code in your editor if you either step away from it and are just looking at the code not really able to see the text itself but just the shape that it makes. If you have some shorter lines and then a handful of longer lines, you might be able to see like, oh, like these are multiple conditionals happening, which I think is kind of related to what you're saying about taking a piece of code and then diagramming it out to really see the different paths.

And I know that that can also be obscured a little bit if you are stylistically using different syntax. Like, if you are using a guard clause to return early, that's a conditional, but it gets a bit hidden from the visual representation than if you had written out the full if statement, for example.

JOËL: I think that's a really interesting distinction that you bring up because a lot of languages provide syntactic sugar for common conditional tasks that we do. And sometimes, that syntactic sugar will almost obfuscate the fact that there is a conditional happening at all, which can be great in a lot of cases.

But when it comes to analyzing and particularly comparing different implementations, a second conversion that I like to do is converting all of the conditional code to some standardized form, and, for me, that's typically just your basic if...elsif...else expressions. And so any fancy Boolean operators we're doing, any safe navigation that we're doing around nil, maybe some inline conditionals, early returns, things like that, all of the implicit elses that are involved as well, putting them all into some normalized form then allows me to compare two implementations with each other.

And sometimes, two approaches that we initially thought were identical, just with different syntax, turned out to have slightly different behavior because maybe one has this sort of implicit branch that the other one doesn't. And by converting to a normalized syntax, all of a sudden, this difference becomes super obvious.

To be clear, this is not something I do necessarily in the actual code that I commit, not necessarily writing everything long-form. But definitely, when I'm trying to think about conditional code or analyzing somebody else's code, I will often convert it to long-form, some normalized shape so that I can then see some things about it that were not obvious in the final form. Or to make a comparison with something else, and then you can compare apples to apples and say, okay, both these approaches that we're considering in normalized form, here's what they look like. There's some difference here that we do care about or don't care about.

STEPHANIE: That's really interesting. I find it very curious that there is a value in having the long-form approach of writing the code out and being able to identify things. But then the end result that we commit might not look like that and be shortened and be kind of, quote, unquote, "polished," or at least condensed with syntactic sugar. And I'm kind of wondering why that might be the case.

JOËL: I think a lot of that will come down to your personal or your company's style guide. Personally, I think I do lean a little bit more towards a slightly more explicit form. But there are plenty of times that I will use syntactic sugar as well, as long as everybody knows what it does. But sometimes, it will come at the cost of other analysis techniques. You had mentioned the squint test earlier, which I believe is a term coined by Sandi Metz.

STEPHANIE: I think it might be. That rings a bell.

JOËL: And that is a benefit that you get by writing explicit conditionals all the time. But sometimes, it is much nicer to write code that is a little bit more terse. And so you have to do the trade-offs there.

STEPHANIE: Yeah, that's a really good point.

JOËL: So that's two of the sort of three formats that I was thinking about for converting conditional code to gain more insight. The other format is honestly a little bit weird. It's almost a stretch. But from my time spent working with the Elm language, I learned how to use its type system, which uses a concept called algebraic data types, or some languages will call these tagged unions, some languages will call these sum types. This concept goes by a lot of different names.

But they're used to define types into model data. But there's a really fun property, which is that you can model conditional code using this as well. And so you can convert executable code into these algebraic data types. And now, you can apply a lot of tools and heuristics that you have from the data modeling world to this conditional code.

STEPHANIE: Do you have a practical example?

JOËL: So a classic thing that data modelers will say is you should make impossible states impossible. So in practice, this means that when you define a type using these algebraic data types, you should not be able to create more distinct values than are actually valid in this particular system. So, for example, if a value is required to always be present for something and there's no way in the system for a value to become not present, then don't allow it to be nullable.

We do something similar when we design a database schema when we put a null false on a column because we know that this will never be null. And so, why allow nulls when you know they should never be there? So it's a similar thing with the types. This sort of analysis that you can do looking at...the fancy term is the types cardinality. I'll link to an article that digs into that for people who are curious.

But that can show you whether a type can represent, let's say, ten possible values, but the domain you're trying to model only has 5. And so when there's that discrepancy, there are five valid values that can be modeled by your type and an additional extra five that are not valid that just kind of shake out from the way you implemented things. So you can take that technique and apply it to a conditional that you've converted to algebraic data type form. And that can help find things like paths through your conditional code that don't line up with the problem that you're trying to solve.

So going back to the example I talked about earlier of a multi-step form with three different steps, that's a problem that should have three paths through your conditional. But depending on your implementation, if it's a bunch of independent if clauses, you might have a bit of a combinatorial explosion. And there might be 25 different paths through that chunk of code. And that means three of them are the ones that your problem wants, and then the extra 22 are things that should quote, unquote, "never happen," but we all know that they eventually will. So that kind of analysis can help maybe give you pointers to the fact that your current structure is not well-suited to the problem that you're trying to solve.

STEPHANIE: I think another database schema example that came to mind for me was using an enum to declare acceptable values for a field. And, yeah, I know exactly what you mean when working with code where you might know, because of the way the business works, that this thing is impossible, and yet, you still have to either end up coding defensively for it or just kind of hold that complexity in your head. And that can lead to some gnarly situations, and it makes debugging down the line a lot more difficult too.

JOËL: It definitely makes it really hard for somebody else to know the original intention of the code when a conditional has more paths through it than there actually are actual paths in the problem you're trying to solve. Because you have to load all of that in your head, and our programmer brains are trained to think about all the edge cases, and what if this condition fires but this other one doesn't? Could that lead to a bug? Is that just a thing that's like, well, but the inputs will never trigger that, so you can ignore it? And if there are no comments to tell you, and if there are comments, then do you trust them? Because it --

STEPHANIE: Yes. [laughter] I'll just jump in here and say, yeah, I have seen the comments then conflict with the code as well. And so you have these two sources of information that are conflicting with each other, and you have no idea what is true and what's not.

JOËL: So I'm a big fan of structuring conditional code such that the number of unique paths through a set of conditions is the same as the sort of, you might say, logical paths through the problem domain that we haven't added extra paths, just sort of accidentally due to the way we implemented things.

STEPHANIE: Yeah. And now you have three different ways to visualize that information in your head [laughs] with these mental models.

JOËL: Right. So from taking code that is conditional code and then transforming it into one of these other representations, I don't always do all three, but there are tools that I have. And I can gain all sorts of new insights into that code by looking at it through a completely different lens.

STEPHANIE: That's super cool.

JOËL: So the last episode, you had mentioned that you were going to try a soup club. How did that turn out?

STEPHANIE: It turned out great. It was awesome, the inaugural soup group. I had, I think, around eight people total. And I spent...right after work, I went straight to chopping celery [laughs] and onions and just soup prepping. And it was such a good time. I invited a different group of friends than normally come together, and that turned out really well. I think we all kind of had at least one thing in common, which was my goal was just to, you know, have my friends come together and meet new people too.

And we had soup, and we had bread. Someone brought a spiced crispy chickpea appetizer that went really well inside of our ribollita vegetable bean soup. And then I had the perfect amount of leftovers. So after making a really big batch of food and spending quite a long time cooking, I wanted to make sure that everyone had their fill. But it was also pretty nice to have two servings left over that I could toss in the freezer just for me and as a reward for my hard work.

And then it ended up working out really well because I went on vacation last week. And the night we got back home, we were like, "Oh, it's kind of late. What are we going to do for dinner?" And then I got to pull out the leftover soup from my freezer. And it was the perfect coming home from a big trip, and you have nothing in your fridge kind of deal. So it worked out well.

JOËL: I guess that's the advantage of hosting is that you get to keep the leftovers.

STEPHANIE: It's true.

JOËL: You also have to, you know, make the soup. [laughs]

STEPHANIE: Also true. [laughs] But like I said, it wasn't like I had so much soup that I was going to have to eat it every single day for the next week and a half. It was just the amount that I wanted. So I'm excited to keep doing this. I'm hoping to do the next soup group in the next week or two. And then some other folks even offered to host it for next time. So maybe we might experiment with doing a rotating thing. But yeah, it has definitely brought me joy through this winter.

JOËL: That's so lovely. What else has been new in your world?

STEPHANIE: I have a clarification to make from last week's episode. So last week, we were talking about hexagons and tessellation. And we had mentioned that hexagons and triangles were really strong shapes. And we mentioned that, oh yeah, you can see it in the natural world through honeycomb. And I've since learned that bees don't actually build the hexagon shape themselves.

That was something that scientists did think to be true for a little bit, that bees were just geometrically inclined, but it turns out that the accepted theory for how honeycomb gets its shape is that bees build cylindrical cells that later transform into hexagons, which does have a lot of surface area for holding the honey, though the process itself is actually still debated by scientists.

So there's some research that has supported the idea that it's formed through physical forces like the changing temperature of the wax that transforms it from a cylinder shape into a hexagon, though, yeah, apparently, the studies are still a bit inconclusive. And the last scientific paper I read about this, just to really get my facts straight [laughs], they were kind of exploring aspects of bee behavior that led to the hexagons eventually forming because that does require that the cylinders are perfectly the same size and are at least built in a hexagonal pattern, even though the cells themselves are not hexagons.

JOËL: Fascinating. So it sounds like it's either a social thing where the bees do it based off of some behavior. Or if it's a physical thing, it's some sort of like hexagons are a natural equilibrium point that everything kind of trends to, and so as temperature changes, the beehive will naturally trend towards that.

STEPHANIE: Yeah, exactly. I have a good friend who is a beekeeper, so I got to pick her brain a little bit about honeycomb. [laughs]

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JOËL: So in the past few episodes, we've talked about books we're reading, articles that we're reading. This is kind of turning into the Stephanie and Joël book club.

STEPHANIE: I love it.

JOËL: That got me thinking about things that I've read that were impactful in the past year. So I'm curious for both of us what might be, let's say, the top two or three most impactful articles that you read in 2022. Or maybe to put it another way, what are the top two or three articles that you reference the most in conversations with other people?

STEPHANIE: So listeners might not know this, but I actually joined thoughtbot early last year in February. So I was coming into this new job, and I was so excited to be joining an organization with so many talented developers. And I was really excited to learn from everyone. So I kind of came in with really big goals around my technical growth. And the end of the year just passed, and I got to do a little bit of reflection. And I was quite proud of myself actually for all the things that I had learned and all the ways that I had grown.

And I was reminded of this blog post that I think I had in the back of my mind around "Coachability" by Cate, and she talks about how coaching is different from mentorship. And she provides some really cool mental models for different ways of providing support to your teammates. Let's say mentorship is teaching someone how to swim, and maybe helping someone out with a task might be throwing them a life raft.

Coaching is more like seeing someone in the water, but you are up on a bridge, and you are kind of seeing all of their surroundings. And you are identifying ways that they can help themselves. So maybe there's a branch, a tree branch, a few feet away from them. And can they go grab that tree branch? How can they help themselves?

So I came to this new job at thoughtbot, and I had these really big goals. But I also knew that I wanted to lean on my new co-workers and just be able to not only learn the things that I was really excited to learn but also trust that they had my best interests in mind as well and for them to be able to point out things that could help my career growth.

So the idea of coachability was really interesting to me because I had been coming from a workplace that had a really great feedback culture. But I think this article touches on what to do with feedback in a way that I hadn't seen before. So she also describes being coachable as having two axes, one of them being receptiveness to feedback and the other being actionability in response to feedback.

So receptiveness is when you hear feedback; do you listen to it? Do you work through it? How does that feedback fit into your mental model of your goals and your skills? And then actionability is like, okay, what do you do with that? How do you change your behavior? How do you change the way you approach problems? And those two things in mind were really helpful in terms of understanding how I respond to feedback and how to really make the most of it when I receive it.

Because there are times when I get feedback, and I don't know what to do with it, you know, maybe it just wasn't specific enough. And so, in that sense, I want to work on my actionability and figuring out, okay, someone said that testing would be a really great opportunity for me to learn. But what can I do to learn how to write better tests? And that might involve figuring that out on my own, like, what strategies work for me. Or that might involve asking them, being like, "What do you recommend?"

So yeah, I had this really big year of growth. And I'm excited to keep this mental model in mind when I feel like I might be stuck and I'm not getting the growth that I want and using those axes to kind of determine how to move forward.

JOËL: I think the first thing that comes to mind for me is the episode that you and I did a while back about the value of precise language. For example, you talked about the distinction between coaching and mentorship, which I think in sort of colloquial speech, we kind of use interchangeably. But having them both mean different things, and then being able to talk about those or at least analyze yourself through the lens of those two words, I think, is really valuable and may be helping to drive either insights or actions that you can take. And similarly, this idea of having two different axes for receptiveness versus...was it changeability you said was the other one?

STEPHANIE: Actionability.

JOËL: Actionability, I think, is really helpful when you're feeling stuck because now you can realize, oh, is it because I'm not accepting feedback or not getting good feedback? Or is it that I'm getting feedback, but it's hard to take action on it? So just all of a sudden, having those terms and having that mental model, that framework, I feel like equips me to engage with feedback in a way that is much more powerful than when we kind of used all those terms interchangeably.

STEPHANIE: Yeah, exactly. I think that it's very well understood that feedback is important and having a good feedback culture is really healthy. But I think we don't always talk about the next step, which is what do you do with feedback? And with the help of this article, I've kind of come to realize that all feedback is valuable, but not all of it is good. And she makes a really excellent point of saying that the way you respond to feedback also depends on the relationship you have with the person giving it.

So, ideally, you have a high trust high respect relationship with that person. And so when they give you feedback, you are like, yeah, I'm receptive to this, and I want to do something about it. But sometimes you get feedback from someone, and you might not have that trust in that relationship or that respect. And it just straight up might not be good feedback for you.

And the way you engage with it could be figuring out what part of it is helpful for me and what part of it is not? And if it's not helpful in terms of helping your growth, it might at least be informative. And that might help you learn something about the other person or about the circumstances or environment that you're in.

JOËL: Again, I love the distinction you're making between helpful and informative.

STEPHANIE: Yeah. I think I had to learn that the hard way this year. [laughs] So, yeah, I really hope that folks find this vocabulary or this idea...or consider it when they are thinking about feedback in terms of giving it or receiving it and using it in a way that works for them to grow the way they want to.

JOËL: I'm curious, in your interactions, and learning, and growth over the past year, do you feel like you've leaned a little bit more into the mentorship or the coaching side of things? What would you say is the rough percentage breakdown? Are we talking 50-50, 80-20?

STEPHANIE: That's such a good question. I think I received both this year. But I think I'm at a point in my career where coaching is more valuable to me. And I'm reminded of a time a few months into joining thoughtbot where I was working and pairing with a principal developer. And he was really turning the workaround on me and asking, like, what do I want to do? What do I see in the code? What areas do I want to explore?

And I found it really uncomfortable because I was like, oh, I just want you to tell me what to do because I don't know, or at least at the time, I was really...I found it kind of stressful. But now, looking back on it and with this vocabulary, I'm like, oh, that's what true coaching was because I gained a lot of experience towards my foundational skill set of figuring out how to solve problems or identifying areas of refactoring through that process.

And so sometimes coaching can feel really uncomfortable because you are stretching outside of your comfort zone and that your coach is hopefully supporting you but not just giving you the help but teaching you how to help yourself.

JOËL: That's a really interesting thing to notice. And I think what I'm hearing is that coaching can feel less comfortable than mentoring because you're being asked to do more of the work yourself. And you're maybe being stretched in some ways that aren't exactly the same as you would get in a more mentoring-focused scenario. Does that sound right?

STEPHANIE: Yeah, I think that sounds right because, like I said, I was also receiving mentorship, and I learned about new things. But those didn't always solidify in terms of empowering me next time to be able to do it without the help of someone else. Joël, what was an article that really spoke to you this last year?

JOËL: So I really appreciated an article by Adrianna Chang, who's a developer at Shopify, about "Refactoring Legacy Code with the Strangler Fig Pattern." And it talks about this approach to moving refactoring code from one implementation to another. And it's a longer-ranged process, and how to do so incrementally. And a big theme for me this year has been refactoring and incremental change.

I've had a lot of conversations with people about how to spot smaller steps. I've written an article on working incrementally. And so I think this was really nice because it gave a very particular technique on how to do so with an example. And so, because these sorts of conversations kept coming up this year, I found myself referencing this article all the time.

STEPHANIE: I really loved this article too. And this last year, I also saw a strangler fig tree for the first time in real life in Florida. And I think that was after I had read this article. And it was really cool to make the connection between something I was seeing in nature with a pattern in software development or technique.

JOËL: We have this metaphor, and now you get to see the real thing. I was excited because, at RubyConf Mini this year, I actually got to meet Adrianna. So it was really cool. It's like, "Hey, I've been referencing your article all year. It's super cool to meet you in person."

STEPHANIE: That's awesome. I love that, just being able to support members of the community. What I really liked about the approach this article advocated for is that it allowed developers to continue working. You don't have to halt everything and dedicate time to refactor and not get any new feature work done. And that's the beauty of the incremental approach that you were talking about earlier, where you can continue development. Sometimes that refactoring might be paused for some reason or another, but then you can pick back up where you left off.

And that is really intriguing to me because I think this past year, I was working on a client where refactoring seemed like something we had to dedicate special time for. And it constantly became tough to prioritize and sell to stakeholders. Whereas if you incorporate it into the work and do it in a way that doesn't stop the show [laughs] from going on, it can work really well and work towards sustainability and maintenance, which is another thing that we've talked a lot about on the show.

JOËL: Something that's really powerful, I think, with that technique is that it allows you to have all of the intermediate steps get merged into your main branch and get shipped. So you don't have to have this long-running branch with a big change that's constantly going stale, and you're having to keep in sync with the main branch. And, unfortunately, I've often seen even this sort of thing where you create a long-running branch for a big change, a big refactor, and eventually, it just gets abandoned, and you have not locked in any wins.

STEPHANIE: Yeah, that's the worst of both worlds where you've dedicated time and resources and don't get the benefits of that work. I also liked that the strangler fig pattern kind of forces you to really understand the existing code. I think working with legacy code can be really challenging. And a lot of people don't like to do it because it involves a lot of spelunking and figuring out, okay, what's really going on.

But in order to isolate the pieces to, you know, slowly start to stop making calls to the old code, it requires that you take a hard look at your legacy code and really figure it out. And I honestly think that that then informs the new code that you write to better support both the old feature and also any new features to come.

JOËL: Definitely. The really nice thing about this pattern is that it also scales up and down. You can do this really small...even as part of a feature branch; maybe it's just part of your development process, even if you don't necessarily ship all of the intermediate steps. But it helps you work more incrementally and in a tighter scope. And then you can scale it up as big as changing out entire sections of a framework or...I think Adrianna's example is like switching out a data source. And so you can do some really large refactors. But then you could do it as well on just a small feature.

I really like using this pattern anytime you're doing things like Rails upgrades, and you've got old gems that might not convert over where it's like, oh, the community abandoned this gem between Rails 4 and Rails 5. But now you need sort of a bridge to get over. And so I think that pattern is particularly powerful when doing something like a Rails upgrade.

STEPHANIE: Very Cool.

JOËL: So what would be a second article that was really impactful for you in the past year?

STEPHANIE: So, speaking of refactoring, I really enjoyed a blog post called Finding Time to Refactor by a former thoughtboter, German Velasco. He makes a really great point that we should think of completeness in our work, not just when the code works as expected or meets the product requirements, but also when it is clear and maintainable. And so he really advocates for baking refactoring into just your normal development process.

And like I said, that goes back to this idea that it can be incremental. It doesn't have to be separate or something that we do later, which is kind of what I had learned before coming to thoughtbot. So when I was also speaking about just my technical growth, this shift in philosophy, for me, was a really big part of that. And I just started kind of thinking and seeing ways to just do it in my regular process. And I think that has really helped me to feel better about my work and also see a noticeable improvement in the quality of my code.

So he mentioned the three times that he makes sure to refactor, and that is one when he is practicing TDD and going through the red-green-refactor cycle.

JOËL: It's in the name.

STEPHANIE: [laughs] It really is. Two, when code is difficult to understand, so if he's coming in and fixing a bug and he pays the tax of trying to figure out confusing code, that's a really great opportunity to then reduce that caring cost for others by making it clear while you're in there, so leaving things better than you found it.

And then three, when the existing design doesn't work. We, I think, have mentioned the adage, "Make the change easy, and then make the easy change." So if he's coming in to add a new feature and it's just not quite working, then that's a really good opportunity to refactor the existing design to support this new information or new concept.

JOËL: I like those three scenarios. And I think that second one, in particular, resonated with me, the making things easier to understand. And in the sort of narrower sense of the word refactoring, traditionally, this means changing the structure of the code without changing its behavior. And I once had a situation where I was dealing with a series of early return expressions in a method that were all returning Booleans. And it was really hard because there were some unlesses, some ifs, some weird negation happening. And I just couldn't figure out what this code was doing.

STEPHANIE: Did you draw a diagram? [laughs]

JOËL: I did not. But it turns out this code was untested. And so I pretty much just tried, like, it took two Booleans as inputs and gave back a Boolean. So I just tried all the combinations, put it in, saw what it gave me out, and then wrote tests for them. And then realized that the test cases were telling me that this code was always returning false unless both inputs were true.

And that's when it kind of hits me, it's like, wait a minute, this is Boolean AND. We've reimplemented Boolean AND with this convoluted set of conditional code. And so, at the end there, once I had that test coverage to feel confident, I went in and did a refactor where I changed the implementation. Instead of being...I think it was like three or four inline conditionals, just rewrote it as argument one and argument two, and that was much easier to read.

STEPHANIE: That's a great point. Because the next time someone comes in here, and let's say they have to maybe add another condition or whatever, they're not just tacking on to this really confusing thing. You've hopefully made it easier for them to work with that code. And I also really appreciated, you know, I was mentioning how this article affected my thought process and how I approach development, but it's a really great one to share to then foster a culture of just continuous refactoring, I guess, is what I'm going to call it [laughs] and hopefully, avoiding having to do a massive rewrite or a massive effort to refactor.

The phrase that comes to mind is many hands make light work. And if we all incorporated this into our process, perhaps we would just be working all around with more delightful code. Joël, do you have one more article that really stood out to you this year?

JOËL: One that I think I really connected with this year is "Parse, Don't Validate" by Alexis King. Long-time listeners of the show will have heard me talk about this a little bit with Chris Toomey when he was a guest on the show this past fall. But the gist of the article is that the process of parsing is converting a broader type into a narrower type with the potential for errors.

So traditionally, we think of this as turning a string which a string is very broad. All sorts of things are strings, and then you turn it into something else. So maybe you're parsing JSON. So you take a string of characters and try to turn it into a Ruby hash, but not all strings are valid hashes. So there's also the possibility for errors. And so, JSON.parse() could raise an error in Ruby.

This idea, though, can be then expanded because, ideally, you don't want to just check that a value is valid for your stricter rules. You don't want to just check that a string is valid JSON and then pass the string along to the next person. You actually want to transform it. And then everybody else down the line can interact with that hash and not have to do a check again is this valid JSON? You've already validated that you've already converted it into a hash. You don't need to check that it's valid JSON again because, by the nature of being a hash, it's impossible for it to be invalid.

Now, you might have some extra requirements on that hash. So maybe you require certain keys to be present and things like that. And I think that's where this idea gets even more powerful because then you can kind of layer this on top and have a second parsing step where you say, I'm going to parse this hash into, let's say, a shopping cart object. And so, not all Ruby hashes are valid shopping carts.

And so you try to take a broader value and coerce it into a narrower value or transform it into a narrower value and potentially raise an error for those hashes that are not valid shopping carts. And then, whoever down the line gets a shopping cart object, you can just call items on it. You can call price on it. You don't need to check is this key present? Because now you have that certainty.

STEPHANIE: This reminds me of when I was working with TypeScript in the summer of last year. And having come from a dynamically-typed language background, it was really challenging but also really interesting to me because we were also parsing JSON. But once we had transformed or parsed that data into this domain object, we had a lot more confidence about what we were working in. And all the functions we wrote down the line or used on the line, we could know for sure that, okay, it has these properties about it. And that really shaped the code we wrote.

JOËL: So use the word confident here, which, for me, it's a keyword. And so you can now assume that certain properties are true because it's been checked once. That can be tricky if you don't actually do a transformation. If you're just sort of passing a raw value down, you'll often end up with code that is defensive that keeps rechecking the same conditions over and over.

And you see this lot around nil in Ruby where somebody checks for a value for nil, and then inside that conditional, three or four other conditions deep, we recheck the same value for nil again, even though, in theory, it should not be nil at that point. And so by doing transformations like that, by parsing instead of just validating, we can ensure that we don't have to repeat those conditions.

STEPHANIE: Yeah, I mean, that refers back to the analyzing conditional code that we spent a bit of time talking about at the beginning of this episode. Because I remember in that application, we render different components based on the status of this domain object. And there was a condition for when the status was something that was not expected.

And then someone had left a comment that was like, technically, this should never happen. But I think that he had to add it to appease the compiler. And I think had we been able to better enforce those boundaries, had we been more thoughtful around our domain modeling, we could have figured out how to make sure that we weren't then introducing that ambiguity down the line.

JOËL: I think it's interesting that you immediately went to talking about TypeScript here because TypeScript has a type system. And the "f, Don't Validate" article is written in Haskell, which is another typed language. And types are great for showing you exactly like, here's the boundary. On this side of it, it's a string, and on this side here, it's a richly-typed value that has been parsed.

In Ruby, we don't have that, everything is duck-typed, but I think the principle still applies. It's a little bit more implicit, but there are zones of high or low assumptions about the data. So when I'm interacting directly with raw input from a third-party endpoint, I'm really only expecting some kind of raw string from the body of the response. It may or may not be valid. There are all sorts of checks I need to do to make sure I can do anything with it. So that is a very low assumption zone.

Later on, in the business logic part of the code, I might expect that I can call a method on the object to get the price of a shopping cart or a list of items or something like that. Now I'm in a much higher assumption zone. And being self-aware about where we transition from low assumptions to high assumptions is, I think, a really key takeaway for how we interact with code in Ruby. Because, oftentimes, where that boundary is a little bit fuzzy or where we think it's in one place but it's actually in a different place is where bugs tend to cluster.

STEPHANIE: Do you have any thoughts about how to adhere to those rules that we're making so we're not having to assume in a dynamically-typed language?

JOËL: One way that I think is often helpful is trying to use richer objects and to not just rely on primitives all the time. So don't pass a business process a hash and be just like, trust me, I checked it; it's got the right keys because the day will come when you pass it a malformed hash and now we're going to have an error in the business process.

And now we have a dilemma because do we want to start adding defensive checks in the business process to be like, oh, are all our keys that we expect present, things like that? Do we need to elsewhere in the code make sure we process the hash correctly? It becomes a little bit messy. And so, oftentimes, it might be better to say, don't pass a raw hash around. Create a domain object that has the actual method that you want, and pass that instead.

STEPHANIE: Oh, sounds like a great opportunity to use the new data class in Ruby 3.2 that we talked about in an episode prior.

JOËL: That's a great suggestion. I would definitely reach for something like that, I think, in a situation where I'm trying to model something a little bit richer than just a hash.

STEPHANIE: I also think that there have been more trends around borrowing concepts from functional programming, and especially with the introduction of classes that represent nil or empty states, so instead of just using the default nil, having at least a bit of context around a nil what or an empty what. That then might have methods that either raise an error or just signal that something is wrong with the assumptions that we're making around the flexibility that we get from duck typing.

I'm really glad that you proposed this topic idea for today's episode because it really represented a lot of themes that we have been discussing on the show in the past couple of months. And I am excited to maybe do this again in the future to just capture what's been interesting or inspiring for us throughout the year.

JOËL: On that note, shall we wrap up?

STEPHANIE: Let's wrap up. 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: Thank you so much for listening to The Bike Shed, and we'll see you next week.

ALL: Byeeeeeeeeeee!!!!!!!!

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