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The Modern Rubyist: When and How to Use the Latest Features
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The Modern Rubyist: When and How to Use the Latest Features

Lucian Ghindă • September 13, 2024 • Sarajevo, Bosnia and Herzegovina • Talk

Summary of "The Modern Rubyist: When and How to Use the Latest Features"

In this talk presented by Lucian Ghindă at EuRuKo 2024, the focus is on adopting and utilizing the latest features introduced in Ruby, particularly those that have emerged since Ruby 2.7. The speaker emphasizes the importance of evolving with the language rather than holding onto old habits, cautioning against the "Boredom Trap" that can lead to stagnation in a developer's engagement with there codebase.

Key Points Discussed:

  • Evolution of Ruby:

    • Ruby has introduced numerous features over the last five years, including numbered parameters, endless methods, pattern matching, and more. Despite their existence, many developers continue to use outdated syntax and techniques, which limits their code's potential.

  • Purpose of New Features:

    • New features in Ruby serve to simplify coding, enhance readability, and encourage innovative coding practices.

  • Endless Methods:

    • Presented as an engaging solution to reduce line numbers and package multiple definitions in a clear format. An endless method allows defining methods with less syntactic overhead, thus promoting compactness in code.

  • Data Classes:

    • Data classes, introduced in 2022, simplify the creation of immutable objects. They provide a clear structure for holding data without unnecessary boilerplate code, contributing to better management and organization of data structures.

  • Pattern Matching:

    • This feature allows for more declarative and less error-prone handling of data shapes, enhancing the clarity and functionality of branching logic within the code. It also introduces local variable creation dynamically based on matching conditions.

Key Examples:

  • Examples of using endless methods and data classes illustrate the concise effects on code structure.
  • The speaker makes practical suggestions on implementing these features, such as using pattern matching to unpack hashes more elegantly and effectively, promoting cleaner designs.

Conclusions:

  • Developers are encouraged to experiment with new features to appreciate their potential. Ghindă suggests that although there may be discomfort with new syntax, engaging with these changes can lead to a richer understanding and better practices in coding.
  • The emphasis is placed on community feedback and shared exploration among developers as critical to keeping Ruby vibrant and relevant for the future.

In conclusion, the session advocates for experimentation and openness to adopting new Ruby features to avoid stagnation and enhance code quality, ultimately appealing to both novice and seasoned Rubyists to embrace change and creativity within their coding practices.

The Modern Rubyist: When and How to Use the Latest Features
Lucian Ghindă • Sarajevo, Bosnia and Herzegovina • Talk

Date: September 13, 2024
Published: January 13, 2025
Announced: unknown

Explore how Ruby has evolved with features like numbered params, endless methods, and pattern matching. Let’s embrace these changes to future-proof our code rather than sticking to old habits. You will learn how to use the new features, when to apply them, and when to avoid them.

There are almost 5 years since we started seeing many new features and syntax being added to Ruby, and still, a huge part of the developers are not using it. We have become conservative and thus this is a protecting position and when we focus on protecting what we have, we close in and are not focused on evolving and the future. As Matz says in a talk, we need to push forward and adopt new features if we want to avoid the Boredom Trap, where existing developers are getting bored and moving out while new people are not coming in as the language does not evolve to offer new solutions to new problems.

Ruby has evolved a lot since Ruby 2.7 and has added a wide range of new features that can transform both how we think about and write code.

You may have heard about some of them: numbered block params, endless method definition, hash literal value omission, pattern matching, object shapes, or new stdlib/core methods and classes. These features hold immense potential, yet most codebases do not take full advantage of them.

The primary outcome of this talk is to show developers practical knowledge about the new features. They will not only understand what these features do but also when it is a good idea and a bad idea to apply them. It might be that everybody knows about these new features, but adopting them takes work to convince colleagues about the benefits and use cases where new features fit.

In this talk, I will review a series of code snippets taken straight from production and see how they can be improved using the new Ruby features while extracting rules or guides about how and when to apply them.

EuRuKo 2024

00:00:11.240 okay so um this is me I could not find my social media Handler the same on all
00:00:17.400 the the social media so it's different on all of them I'm a I'm a ruby
00:00:22.519 developer since 2007 um and today uh my purpose is to cover a couple of topics
00:00:28.560 uh first I'm going to talk a bit about why adopt new features um and and then I
00:00:34.719 will show you some code samples with these features that are in Ruby since at least Ruby 2.7 some of them since then
00:00:42.039 they they were added these are not let's say the maybe the most um newest or
00:00:49.280 maybe the most creative maybe for you but I chose them uh with with some because I wanted one to pick something
00:00:56.879 that I think can change the code shape so how the code looks like when we are writing it I also choose them because I
00:01:03.960 needed to choose just some of them to present them in 30 minutes um and I also choose them because usually when at
00:01:10.880 least what I see when I curate the newsletter when people are sharing code samples with this ones either over
00:01:18.280 social media or edit or in some other places there are a lot of comments and a lot of debates about them and my purpose
00:01:25.439 my purpose here is to show you some code samples and maybe inspire you to take a look at them I'm not going to say this
00:01:31.000 is good and this is bad but more so like hey here it is how it can look if you want to give it a try and lower the
00:01:38.240 feeling of unfamiliarity of them because maybe they seem strange when we look at them and also because inspired by the
00:01:46.680 morning yeah we maybe want to play with some strange ideas about how the code might look like and and one of the
00:01:53.479 Hidden reason is that sometimes when we read a pool request where when you debate a piece of code we might confuse
00:02:00.399 I think readability and understand understandability with being familiar
00:02:06.159 and I would like to make them a bit more familiar so maybe we can judge them based on their own merits and not
00:02:11.440 because we find them very strange and we did not s too much maybe so um I I I was
00:02:18.879 a silent consumer let's say of Ruby goodies since 2007 but only in the
00:02:25.000 recent years I decided that I want to get involved now I'm not a ruby committer I'm just I'm a developer that
00:02:31.160 uses Ruby and I ask myself what can I do to contribute to the community and one of the things that I was interested in
00:02:38.239 it was how can I help grow the Ruby community and I think I'm trying with my newsletter to to publish it free and
00:02:45.120 maybe there are other people than only us that knows Ruby that looks at a piece of code and maybe they say hey what is
00:02:51.840 this strange language let's give it a try let's say and but the second um let's say a second objective or topic
00:02:58.840 for me will be how can can I keep Ruby relevant for 30 years or more because I plan to use Ruby for at least 30 years
00:03:05.840 more um and and here again I'm not a like I'm not a core committer so my my
00:03:11.319 question for myself was and I invite you also to to think this like how can I do this from my role as a developer if you
00:03:18.599 are not a a committer so I started I started running Ruby coming from um I
00:03:25.519 was writing python back then and some PHP on the side and I was trying to build uis with these two that maybe very
00:03:33.120 few people know scriptaculous and prototype.js which I think they were created by ruist if I'm not mistaken um
00:03:42.640 and and I I learned in faculty Java and c and when I when I saw Ruby it felt
00:03:49.239 strange and almost illegal to write that kind of code you know like like it
00:03:54.360 should not be possible they should not allow you to make this but for me I love Ruby and I this I felt that Ruby it's
00:04:01.599 creativity and freedom for me and it's it's it's a creativity because we are
00:04:06.799 talking in this community more than than I found in others maybe but I don't know others too much so I'm just talking
00:04:12.519 about ourselves we talk about beautiful code and and Beauty in in in a kind of
00:04:18.000 embedded AI Vector beautiful is very close to Art and is very close to
00:04:23.320 creativity in in my mind map and it's freedom because also Dave mentioned in the morning I feel like Ruby fits the
00:04:30.240 way I think but I also it fits different ways of thinking so everybody can be
00:04:35.880 free to express themselves uh in Ruby so just just just a and and how I see in a
00:04:41.800 way um the talking about new features how I see the evolution from the
00:04:46.840 perspective of someone that just consumes I see like for example just asking how can you calculate the sum of
00:04:52.759 all elements um of an array of integers so maybe years ago I don't know 20 30
00:04:59.280 years ago so maybe we could have written Assembly Language I did not wrot this I I searched for it on the internet I even
00:05:06.080 asked chpt to explain it to me it seems okay reading those things there but the
00:05:11.720 idea that when I look at this code it's it's of course low level and it even it's easy to read in some kind of ways
00:05:18.520 but I don't think in these keywords in my head I have to make a translation when I think about a business domain and
00:05:24.680 I would write to calculate the sum of all elements I have to do a translation between how I think about that and in
00:05:30.720 this one I'm not saying this is bad I think we need sometimes to write maybe this type of code and then maybe we got
00:05:36.400 to the C kind of languages I'm not going to do a history but just saying right which seems which seems a bit better and
00:05:44.080 and and even compact in some way but still still you have to take a lot of decisions thinking that the objective is
00:05:50.720 to calculate the sum so I have to think about an iterator and where does it start and when does it end and and so on
00:05:56.520 and so forth so so then maths uh think about a concept to compress all
00:06:02.479 of this called each and wrote the C part of this one so that we can write this
00:06:08.280 type of code where I don't think where it start and where it ends and how to name an iterator and what is the
00:06:13.479 increment I just think that I want to make a sum and more so Ruby offers a a better compression of complexity if I
00:06:20.680 can say making it a DOT sum okay and with this and this is an important piece
00:06:26.800 that I want to put there about trying new features is like learning new Concepts on new words in a dictionary it
00:06:33.680 allows you if you know them to to be able to address bigger problems and describe them more so having a sum I can
00:06:41.479 or having the concept of a map I can just write map there and then move over to a more complex algorithm that I want
00:06:47.440 to tackle and not write the the part there but I'm not going through all all this Evolution my purpose is mostly to
00:06:54.759 say that I think for me Ruby what does it bring with a with having a wide area of of what of what the language offers
00:07:02.520 it offers me what I I would like to call a compression of complexity into some kind of abstractions if you want but
00:07:08.599 let's call them maybe some new words or concepts that we can use so that we can
00:07:13.960 write concise code that is still readable and that for me goes a bit near
00:07:19.720 Simplicity or making things simpler and so just to summarize one of
00:07:26.160 the ways that I think we should learn new features is that in in as in language people are saying that words
00:07:32.280 shape our thinking and our reality the same way the features of a programming language and how a programming language
00:07:39.039 is can shape the way we we think and how how we think about the problem how we are defining it and and how the code we
00:07:46.560 write and now in the same time Ruby it's a mature programming language I don't
00:07:51.639 know if you noticed that but is is not new and that's a good thing right but it might have a dilemma as as and in
00:07:58.280 general major programming languages have a dilemma as they mature it changes they need to change to stay relevant and
00:08:04.960 address new problems and improve usability but then they have to tackle the idea to introduce new features and
00:08:11.599 paradig paradig paradig whatever can disrupt the
00:08:17.879 the codebase and ecosystem and and I I paraphrased the innovators dilemma which is a famous book in startup World saying
00:08:25.199 that we might have a programming language dilemma and that is long time users of the language may prefer
00:08:31.520 stability and back or compatibility while newer users or the ones that are using the language at the
00:08:37.800 edge or pushing where it is used May advocate for more radical changes and to
00:08:43.080 keep the language modern and efficient for them right so so it's a it's a dilemma um and and I I I think here in
00:08:51.480 if I look at the Ruby Community I could say that probably most of us are senior or at least Medium as a general feeling
00:08:58.600 of the community probably I did not do a study but that's my feeling right so we might go into kind of
00:09:05.000 expert how to say expert not dilemma but trick that is that is a benefit of being
00:09:11.440 an expert that the more you use something in in our case programming this programming language the current
00:09:17.079 set of capabilities the better our brain fits them and thinks in them right and
00:09:22.680 we might become a bit conservative toward what's new and that's not a big problem but there is a risk there and
00:09:29.120 for for example it's probably fine to be skeptic about what's new sometimes and say I will stay a bit behind and see if
00:09:37.120 it works what what is added but the risk here is when this attitude goes to I'm
00:09:42.440 not even going to try it right so I I ignore it completely or it is okay to
00:09:47.959 use what you know and say okay I will not learn this new thing that was added now let's see but the risk here is that
00:09:55.760 because you we stick with what we know we are trying to change problems to fit the solutions that we know right we
00:10:01.839 change the problem to fit the solution and so in a way it's like we we have a
00:10:07.000 lot of discussions about these methods and it's most like I thought about it and it feels like I almost used them but
00:10:14.399 did not actually use them in the code so and talking about the community part because that was also a thing of of
00:10:20.279 myself is that when we we are focusing on being conservative let's say it feels
00:10:26.560 stiff or rigid or inelastic and that that goes to a close community in some way having high expectations for someone
00:10:34.440 that is new so so I call this a risk in a way and this risk comes out of our love for Ruby in a way that because we
00:10:41.880 want to protect it that much right we want to protect it we don't see that we are actually shielding it from the
00:10:48.040 future and that might be a risk I'm not saying this is happening I'm saying it might be a risk so but there is a
00:10:53.880 solution to this and this is why I'm here to P you that we have to be open to new and that means to EXP experiment
00:10:59.639 with these new features I'm not saying adopt them all from tomorrow but try to experiment with them choose what works
00:11:06.160 for you and be open a bit to re to break and rebuild for this and this is a path
00:11:12.000 to stay relevant so coming back to my idea this my pitch is simple just adob new features try to experiment with them
00:11:19.200 for real in in your code base and see what works and provide feedback to core
00:11:25.040 committers and to mats about your use case and how it works and what works and
00:11:30.240 whatnot all right so at the beginning for me Ruby felt
00:11:35.839 strange and even lenus tal said about us when talking about the success of of jit
00:11:41.240 like like he said like the Ruby people strange people started using git and suddenly it just exploded so my idea
00:11:48.519 here today is like I feel we can do this again because I feel Ruby inspired some other languages before when it was fresh
00:11:56.480 and challenging and I think we can do it again this one this feeling so let me talk
00:12:02.279 about the endless method then showing some code because that was an introductory speech so endless method
00:12:08.480 was introducing Ru 3.0 in 2020 it was it started as an April's full joke but now
00:12:15.360 it's actually in the language and it looks like this it's a Def and then the name of the method and can be some
00:12:20.720 parameters and eagle and something and sometimes people say it's very strange for me to read this but for me if I read
00:12:27.160 it I read it like this def exist as equal to the active record expression I
00:12:33.079 I'm just saying for me I'm not saying for you should read it like this right but we had we had this one line or one
00:12:39.279 Expressions before right we you can write this is valid rubby code still this one and the other ones so it's not
00:12:46.360 quite strange to have everything in one expression and I'm using one expression and not one line and I will show you
00:12:51.519 some examples about this right so my assertion is the following if I blur a bit out these ones and let me blur them
00:12:58.279 more do you feel that it's a bit confusing that the first definition it stops at the end of the line and then it
00:13:04.959 comes a new definition maybe you feel a bit strange about this one right it feels like something stops there and
00:13:10.760 something starts so for me the endless method just adds a Clarity to all of these things right it puts an eagle
00:13:17.320 there separating the definition of the body so let me show some examples this
00:13:22.560 one from Mastodon is not actually from your source code but it's a change that I was thinking can be good I did not
00:13:27.800 submited the pr because I don't want the maintainers to just read a small change but I was browsing and reading some open
00:13:33.839 source code to get some inspiration about how other people are writing code and so this kind of thing there you see
00:13:39.399 like and I found it nice you know it's it's like declaring a do name in The Domain that they are they they are
00:13:45.880 programming there instead of working with numbers and I was thinking you know what this is a great fit for Endless
00:13:51.360 method here and if I do it like this then I can group them in a very nice way
00:13:56.680 like this and so I can read them very quick in some way and I can even group them have a visually right and so going
00:14:05.720 a bit in why to use it so the first thing is that you can write small utility methods and it does not increase the line numbers at all then you can
00:14:14.079 even use the idea that is hard to make it long as a point to not make methods complex so for example this is this is a
00:14:20.959 piece of code that takes the status ID and I can write it like this specifically to make it hard to add more
00:14:27.600 things to it you have to change it into a normal method and then multi-line so this works these constraints can work in
00:14:34.639 before adding more fear to adding more things here to think do I really need to add them here do I really want to
00:14:40.759 transform this into a normal method right so using this against the change not against being open to change but
00:14:47.199 thinking more about the change and and of course because it does not add it
00:14:52.720 does not add more lines of code we can use it for naming and I think this is the best one of the best cases so let's
00:14:59.440 say we have in code these kind of things user settings and some team settings and some default settings and what I can do
00:15:06.160 is just I can transform this one into endless methods with with better names that that are searchable right like this
00:15:14.279 and then I can compose them into a nicer method that says you know user settings it's personal preferences and or default
00:15:22.160 user preferences and team team settings it's team preferences or default team preferences so so it it goes well with
00:15:29.600 naming it also goes well with defining some predicates so you don't work with negative logic if you want to just
00:15:35.680 renaming them you're you don't have to and it also works well with data object that we'll we'll discuss later that it
00:15:43.440 keeps the object small defining against some predicates there and of course it might have some gas like like for
00:15:49.399 example you cannot you cannot use it directly or at least when I did this Benchmark to to defi to define a Setter
00:15:57.800 method you see the URL it has an equal there it's a Setter right so maybe maybe that was by Design or not but the idea
00:16:04.800 this is my idea to use it and if you find yourself that you really want to use it a lot like this then you can
00:16:10.079 submit a proposal to make it work but you have to show a a more normal case
00:16:15.440 and not a theoretical one I would like this to work because I think it should work right it but when you show
00:16:21.759 application code and and a case for it it makes it easy also for rubby committers to decide should I put the
00:16:28.199 effort into make this thing anyhow talking a bit about changing Cod shape you remember that I said it's it's one
00:16:34.360 expression and not one line here is an endless method multiline that that works this is valid code and it feels to me
00:16:41.160 like a bit like it's a you know I'm not going to say elixir with gu CLA it but it's like I was putting a kind of gu
00:16:46.920 Clause directly in the same line with the definition here or and I know what
00:16:52.319 you're thinking I know what you're thinking I I just took a screenshot from there what if my rubocop will be will be
00:16:58.639 all over the air if I write over the air if I write this kind of code yes but I'm
00:17:03.759 I'm just saying play with it for fun or disable that maybe starting in your personal projects to play with it and
00:17:10.039 see how it works because I can push it further and put a case there like this or I can align it like this and it
00:17:17.120 almost feels like it has an end but don't get tricked it it misses an end there to to be a real method right and
00:17:24.199 of course you can write you can play in many more ways and these are just some examples with it so it might change a
00:17:29.240 bit the way the code looks like maybe for some of you in a good ways maybe for some of you you don't find it good but
00:17:35.559 they work and a benefit of the Endless method a side effect of it it's it's grapp in the sense that for example if I
00:17:42.760 grap by the name of a method I get the line but if I grab an endless method I
00:17:48.160 get the body of the method where it was found and I think that that's that could
00:17:53.280 explore as Casper was reading some code bases right you grap about something and you can see them
00:17:59.640 now another favorite of mine it's data class and I really think this this should not be that unfamiliar or or it
00:18:06.840 should be used more and probably it is used more but I did not find too many too many places so data class was
00:18:13.120 introduced in 2022 and what is a data object or a data value object if you
00:18:18.679 want a convenient way to define a simple classes for Value alike objects and they have a property it's immutable it has a
00:18:25.240 simple interface can be comparable by value and by type and here's the interface of this class it's it's very
00:18:31.799 simple and I I totally love that this is an object that is a very simple object and and talking about it it goes like
00:18:38.520 this you use data Define you give it the attributes that you want and you can instantiate it in a lot of um in a lot
00:18:46.280 of forms for example with required keyword arguments or with positional arguments or with this form that I don't
00:18:53.679 I couldn't find the official name for it I call it an alternative form construct or someone said that
00:18:59.720 with with square or even with squares and keyword like arguments I don't know
00:19:05.080 the proper name but in the break if you know tell me so that I changed this and and it has no Setters I said it's
00:19:11.520 immutable so you cannot change the attributes that you give it at at the initializing of it and that that's a
00:19:17.240 benefit this one you even you cannot change some custom instance variable that you are trying to Define inside it
00:19:23.880 so not the one initializers you cannot change them and that again it's a good property of this this one and it's
00:19:30.039 frozen by default so you just create it and it's there cannot be changed with an
00:19:35.280 atics but we don't go into that um that's sorry you know it from others
00:19:40.960 because you can trick it giving a hash as initializer and changing the hash itself if you don't put effort to make
00:19:46.799 it frozen so you don't reassign the instance variable you you just change the object that is there but that is not
00:19:54.280 specific to data product and sometime that makes for a cool trick but okay a cool nice why use it so the first thing is that
00:20:01.640 you want to keep data together and give it a name and again I think that's the main case for it in some ways as I see
00:20:07.919 it so for example if you are writing an a client for an external API and you read a response you can pack it in a
00:20:14.799 response data object or I don't know some interval together day start time and so on uh but going on with the
00:20:20.440 response because I think maybe everybody at some point will write a kind of client for an external service in some
00:20:25.520 ways or others right you can write it like this and you might ask yourself already why not use a hash for that okay
00:20:32.559 okay first question is the hash is not immutable in this case but maybe you can make it right but this the a better
00:20:40.320 response for this is that the data object has a naming so you can search
00:20:45.440 for it you can say now I want to add rate limiting headers inside it and where it is used and you can grape for
00:20:51.880 it or in your editor you can you can search and find the definition and changes there while the hash you have to
00:20:56.919 write for it and then think is this really the format that I wanted before or I use it in a different place here
00:21:03.360 and you can of course add virtual attributes if you want or computered attributes or small um behavior on it
00:21:11.240 that you cannot do on the hash or you can compose it again with good naming
00:21:16.720 right I want to add raid limiting but I I add a raid limiting that is also data object so I make sure that when I pass
00:21:23.320 this response between multiple objects no nothing will change it I can read it
00:21:28.960 I can do something with it but it will not be changed um so it allows composition and
00:21:34.400 a cool thing if you are writing this kind of code before you can replace it with one line if you don't need not
00:21:41.240 immutable mutable right or you you can you can inherit from it if you want you can and this is a real code I was
00:21:47.679 reading the open source the deod in project and here is a code using rails so they Define a list of reasons with
00:21:54.120 some attributes they create data object out of those they send it to I had some they send it to the inum and
00:22:02.559 then they use that that constant in views so now everything is the same if
00:22:07.919 you want to access some attributes in the code base it has the same kind of thing another one hash value Mission
00:22:16.360 other I'm going very quickly through them but I want to arite to pattern matching very quickly so hash value
00:22:21.400 Mission what is this this is one introduced in 2021 and it goes like this
00:22:27.000 what I like about this a lot is that if you want to use it you have to have the same names it it forces you to be
00:22:33.960 consistent so here is a piece of quote maybe someone wrote at the top of file or somewhere website and from and then
00:22:39.480 in some other part it wants to do URL and source and these are different names for the same thing so first I want to
00:22:46.080 make them the same like this right and then the question is do I really need to
00:22:52.120 provide the source and URL here so that this hash is created and I
00:22:57.960 can take the out and Ruby will create the hash for me and Ruby searches in the local context local variables or local
00:23:05.480 context of the object either method names or local variables let's say um I
00:23:10.960 can I can go further and combine the data object with this one here and so
00:23:16.360 again having different names I will have for example someone wrote something like this all over the place with what is a
00:23:22.200 URL or address and so on I make them the same first now the code already looks nice just forcing me to do that but this
00:23:28.840 in my case and then I take out these values and you can can also see here
00:23:34.159 that this value Omission works also for keyword arguments and it's important to remember
00:23:40.120 this thing that the value disappears because we'll use not the same thing but the same idea in the pattern matching um
00:23:46.400 in in some ways so I remove this ones and now this code for me flows very
00:23:51.480 nicely some data at the top and that flows to the other lines or this is how I see it in in my mind so so why use it
00:23:59.799 very simple because simplify naming and reduce repetition and focus what matters as a side effect if you want to use on
00:24:06.760 the reserve keywords and you might have written like this you know you cannot just write class there as a variable
00:24:13.000 name you might have written this the author of The Proposal maybe Sugo or
00:24:19.000 suugo MAA I'm not sure if I pronounce it well proposed that you can actually use
00:24:24.159 this uh construct to do that and I did a benchmark he also did a men Benchmark
00:24:29.360 and it's actually almost three times faster than using The Binding I'm not
00:24:34.919 sure why but it's just faster and we go to pattern matching which I think has
00:24:40.039 the most chances to change the way we the the shape of our code let's say how
00:24:45.760 how the code looks like so let's say I'm I'm listening to a stream of data that
00:24:50.840 comes as a hash from an API or somewhere and I I want to just process the one that has Type push so I use a data
00:24:59.080 object and create a pro class name push notification and then I can use this form of pattern
00:25:06.760 matching and say if notification has this kind of shape that it has a type key name push and then some title and
00:25:14.360 body and push time I can instantiate an object from it and you might ask wait a
00:25:19.960 second from where the title and body and push time are coming from because I did not Define them and you can inspect
00:25:26.320 yourself in Ruby to see what happens you can say I want to print the local variables here and if you do that you
00:25:33.320 see that here the notification exist and here it there are three new variables in
00:25:38.960 your context here created by pattern matching and this comes with a bit of warning pattern matching will create
00:25:45.840 local V variables but if they exist it will change their values but you we have
00:25:51.880 a solution and that is called pinning I don't know the name of this character but uh carrot yes you use that for that now
00:26:00.799 I want to talk about another form so one way to build this is is the following in there is another form of pattern
00:26:07.320 matching that is called rightward operator and it looks like the line seven here you I say notification does
00:26:14.720 it look like what's on the right and of course if if it looks like I want to put in title the value of title and in body
00:26:21.520 the value of body and push time and so on and so forth now this one add a benefit if you want to that if it does
00:26:27.480 not match it throws an exception so you can do something on that part of it or you can say I really don't want to do
00:26:33.919 anything if you don't match not move forward and let's say a request comes to
00:26:39.679 you and says you know what I want you to support more types that are coming like uh email or a messaging thing so I
00:26:47.080 Define so I look at them and I notice they have different uh attributes not
00:26:52.279 the same attributes as the one before so I create new classes for this so then I
00:26:57.760 can use the the third form of pattern matching that is K in it seems like K statement but it's K in and it goes like
00:27:05.039 this I want to say if if what comes the hash is type push then I want the title
00:27:10.440 the body and push time if type is email I want the subject the send the recipient email sent it and if it's
00:27:17.200 message SMS it's I want the message the phone number and sent sent it this does not throw an exception I can go to else
00:27:24.200 there sorry I so why we use pattern matching because first it it opens the
00:27:30.320 possibilities of what we can do with it I feel for I feel for me that it opens
00:27:35.760 the possibility to write code in some very different ways it almost feels like this is a new strange domain of how can
00:27:43.080 I write code with it okay so some some examples you can check the type of a
00:27:48.399 variable but please remember Ru is a dynamically typed language if you do that you renounce the duct typing and
00:27:55.679 also I I feel obliged to put here a from from chavier that it's also constants
00:28:01.320 all the way down in some ways um but what how how you can do that let's say
00:28:06.960 for some whatever reason you have to write this type of code where it matters the type of the parameter okay you can
00:28:14.200 replace that line with this one that almost feels like a type kind of Declaration if you look at it at the
00:28:20.600 beginning of the method let's say if you put it there of course this throws an exception so I can do something with it
00:28:27.200 I can replace it with the in one do you remember there was an in one that throws true and false if I want to um but this
00:28:35.720 this in offers more things not only true and false so I can say I want to pass a hash but I'm only concerned if that hash
00:28:43.399 has a key called hashtag of type array if not don't do anything okay so I'm concerned about
00:28:51.120 does it have a key and I don't want to say if key exist and and so on and so forth this is a simple form to do that
00:28:57.279 and then I can throw it this this call and it works and I can throw this these
00:29:02.399 other calls and they don't work but the code the code is simple there and of
00:29:07.519 course you can you can replace it with a case in if you have to behave differently based on the class of the
00:29:13.480 argument okay um you can use it for error handling and validation so you might say
00:29:19.480 you know I want to validate that the data has a name that is a string and an
00:29:24.640 age that is an integer and and you can use it for that
00:29:30.279 sorry you can use it to to destruct a more complex structure so here I'm looking at the input and I say the input
00:29:36.799 has a key name height that is of type of integer and in in that case put it in the variable name height you don't have
00:29:43.440 to reuse the same name of the variables if you don't want to you can rename them with this construct and then I create an
00:29:50.760 object with it I I cannot go into all the details but I'm just trying to throw different code of you okay then you can
00:29:58.039 destru more complex data as I said in different ways this is another example but what I'm going to do here I'm going
00:30:04.799 to combine this one with endless method so so you can also write it like this
00:30:09.960 one um and now let's go let's let me show you at the end the kind of more complex and more maybe more real example
00:30:16.600 let's say you're an active record in rails and you have an organization and users and admins um and they might have
00:30:23.000 roles and permissions sorry roles and permissions and you can say the following if you create this if you
00:30:29.320 create this deconstruct Keys method you say as a user object when you're called
00:30:35.240 into pattern matching show yourself like this like you see here name username organization and so on when you're
00:30:41.240 called into one of those three forms show yourself like this and then I say to the admin you know what the admin
00:30:47.159 also has permissions add permissions there enroll and then what I can do let's say I want to show Welcome message
00:30:53.399 that is different in a rails helper that is different based on not only if it's an admin or user but based on what other
00:31:01.200 roles it has so for example if it's an admin and it has the role owner I want the organization name and
00:31:09.080 age and so on and I show message if it has it does not have role owner but it
00:31:14.919 has permissions then I show something else if it's a user object and and with
00:31:20.639 a role member do something and if it's if it is a user object with a ro team lead do something else and of course you
00:31:27.320 can achieve this this without pattern matching but I found it nice to look at this and make sure and and see what
00:31:34.200 happens there so you heard this and what now well these are only four of the
00:31:40.360 things that I chose from many features that Ruby has released at least since Ruby
00:31:46.120 2.7 and you will find a lot more of them and you heard some of them but I'm happy to see that slowly it's starting to go
00:31:53.480 also reading some open source code like for example this is a pull request and you see here down an example with
00:32:00.240 pattern matching in the documentation that maybe will go into the documentation of rail so is not only
00:32:06.480 something strange that someone is using somewhere it might go more mainstream if
00:32:11.679 I want to use this word I don't know right something like this but what you can what I think you should do to
00:32:17.279 discover and play with it first disable RoboCop or standard RB in for yourself
00:32:23.639 not in your teams okay for yourself I don't want to say those tools
00:32:28.919 are bad because I think they're very useful I'm saying playing with these features or anyhow rubocop you can make
00:32:34.799 it work with this features because every rule has off on and so on so you don't have to disable completely okay I'm just
00:32:41.080 saying but go to Ruby Lang org news choose one of the years read the beautiful announcements there choose a a
00:32:48.960 feature and start playing with it try to use it in your project or if you prefer a more someone did the summary for you
00:32:55.919 Victor shepelev that you saw in yesterday I think or one of these days day two days ago sorry yes he maintains
00:33:03.600 this Ruby references where he is doing a summary of the biggest highlights and he
00:33:09.279 provides more code examples of those ones if you want to Kickstart and of
00:33:14.840 course I invite you to subscribe to my newsletter where I try to show a lot of types of codes because my newsletter
00:33:20.720 it's a Monday morning summary of Articles discussions in news from the Ruby Community if you want to subscribe
00:33:30.320 there and just a funny joke that I invite you if you want to find out just read the release notes of Ruby
00:33:37.639 3.4 preview CHR at Christmas it is coming um
Lucian Ghindă
@lucianghinda
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