Advertise on podcast: PHP Internals News

PHP Internals News: Episode 103: Disjunctive Normal Form (DNF) Types London, UK Friday, June 24th 2022, 09:07 BST In this episode of "PHP Internals News" I talk with George Peter Banyard (Website, Twitter, GitHub, GitLab) about the "Disjunctive Normal Form Types" RFC that he has proposed with Larry Garfield. The RSS feed for this podcast is https://derickrethans.nl/feed-phpinternalsnews.xml, you can download this episode's MP3 file, and it's available on Spotify and iTunes. There is a dedicated website: https://phpinternals.news Transcript Derick Rethans 0:15 Hi, I'm Derick. Welcome to PHP internals news, a podcast dedicated to explaining the latest developments in the PHP language. This is episode 103. Today I'm talking with George Peter Banyard again, this time about a disjunctive normal form types RFC, or DNF, for short, which he's proposing together with Larry Garfield. George Peter, would you please introduce yourself? George Peter Banyard 0:39 Hello, my name is George Peter Banyard, I work on PHP paid part time, by the PHP foundation. Derick Rethans 0:44 Just like last time, we are still got colleagues. George Peter Banyard 0:46 Yes, we are indeed still call it. Derick Rethans 0:48 What is this RFC about? What is it trying to solve? George Peter Banyard 0:52 The problems of this RFC is to be able to mix intersection and union types together. Last year, when intersection types were added to PHP, they were explicitly disallowed to be used with Union types. Because: a) mental framework, b) implementation complexity, because intersection types were already complicated on their own, to try to get them to work with Union types was kind of a big step. So it was done in chunks. And this is the second part of the chunk, being able to use it with Union types in a specific way. Derick Rethans 1:25 What is the specific way? George Peter Banyard 1:27 The specific way is where the disjoint normal form thing comes into play. So the joint normal form just means it's a normalized form of the type, where it's unions of intersections. The reason for that it helps the engine be able to like handle all of the various parts it needs to do, because at one point, it would need to normalize the type anyway. And we currently is just forced on to the developer because it makes the implementation easier. And probably also the source code, it's easier to read. Derick Rethans 1:54 When you say, forcing it up on a developer to check out you basically mean that PHP won't try to normalize any types, but instead throws a compilation error? George Peter Banyard 2:05 Exactly. It's, it's the job of the developer to do the normalization step. The normalization step is pretty easy, because I don't expect people to do too many stuff as intersection types. But as can always be done as a future scope of like adding a normalization step, then you get into the issues of like, maybe not having deterministic code, because normalization steps can take very, very long, and you can't necessarily prove that it will terminate, which is not a great situation to be in. Imagine just having PHP not running at all, because it's stuck in an infinite loop trying to normalize the format. It's just like, oh, I can't compile Derick Rethans 2:39 Would a potential type alias kind of syntax help with that? George Peter Banyard 2:44 Maybe, I'm not really sure.

PHP Internals News: Episode 102: Add True Type London, UK Thursday, June 2nd 2022, 09:06 BST In this episode of "PHP Internals News" I talk with George Peter Banyard (Website, Twitter, GitHub, GitLab) about the "Add True Type" RFC that he has proposed. The RSS feed for this podcast is https://derickrethans.nl/feed-phpinternalsnews.xml, you can download this episode's MP3 file, and it's available on Spotify and iTunes. There is a dedicated website: https://phpinternals.news Transcript Derick Rethans 0:00 Hi I'm Derick. Welcome to PHP internals news, the podcast dedicated to explaining the latest developments in the PHP language. This is episode 102. Today I'm talking with George Peter Banyard about the Add True Type RFC that he's proposing. Hello George Peter, would you please introduce yourself? George Peter Banyard 0:33 Hello, my name is George Peter Banyard, I work part time for the PHP Foundation. And I work on the documentation. Derick Rethans 0:40 Very well. We're co workers really aren't we? George Peter Banyard 0:43 Yes, indeed, we all co workers. Derick Rethans 0:45 Excellent. We spoke in the past about related RFCs. I remember, which one was that again? George Peter Banyard 0:51 Making null and false stand alone types Derick Rethans 0:53 That's the one I was thinking of him. But what is this RFC about? George Peter Banyard 0:56 So this RFC is about adding true as a single type. So we have false, which is one part of the Boolean type, but we don't have true. Now the reasons for that are a bit like historical in some sense, although it's only from PHP 8.0. So talking about something historical. When it's only a year ago, it's a bit weird. The main reason was that like PHP has many internal functions, which return false on failure. So that was a reason to include it in the Union types RFC, so that we could probably document these types because I know it would be like, string and Boolean when it could only return false and never true. So which is a bit pointless and misleading, so that was the point of adding false. And this statement didn't apply to true for the most part. With PHP 8, we did a lot of warning to value error promotions, or type error promotions, and a lot of cases where a lot of functions which used to return false, stopped returning false, and they would throw an exception instead. These functions now always return true, but we can't type them as true because we don't have it, and have so they are typed as bool, which is kind of also misleading in the same sense, with the union type is like, well, it only returns false. So no point using the boolean, but these functions always return true. But if you look at the type signature, you can see like, well, I need to cater to the case where the returns true and when returns false. Derick Rethans 2:19 Do they return true or throw an exception? George Peter Banyard 2:22 Yeah, so they either return true, or they either throw an exception. If you would design these functions from scratch, you would make them void, but legacy... and we did, I know it was like PHP 8.0, we did change a couple of functions from true to void. But then you get into these weird shenanigans where like, if you use the return value of the function in a in an if statement, null gets because in PHP, any function does return a value, even a void function, which returns null. Null gets coerced to false. So you now get like, basically a BC break, which you can't

PHP Internals News: Episode 101: More Partially Supported Callable Deprecations London, UK Thursday, May 19th 2022, 09:05 BST In this episode of "PHP Internals News" I talk with Juliette Reinders Folmer (Website, Twitter, GitHub) about the "More Partially Supported Callable Deprecations" RFC that she has proposed. The RSS feed for this podcast is https://derickrethans.nl/feed-phpinternalsnews.xml, you can download this episode's MP3 file, and it's available on Spotify and iTunes. There is a dedicated website: https://phpinternals.news Transcript Derick Rethans 0:14 Hi, I'm Derick. Welcome to PHP internals news, the podcast dedicated to explaining the latest developments in the PHP language. This is episode 101. Today I'm talking with Juliette Reinders Folmer, about the Expand Deprecation Notice Scope for Partially supported Callables RFC that she's proposing. That's quite a mouthful. I think you should shorten the title. Juliette, would you please introduce yourself? Juliette Reinders Folmer 0:37 You're starting with the hardest questions, because introducing myself is something I never know how to do. So let's just say I'm a PHP developer and I work in open source, nearly all the time. Derick Rethans 0:50 Mostly related to WordPress as far as I understand? Juliette Reinders Folmer 0:52 Nope, mostly related to actually CLI tools. Things like PHP Unit polyfills. Things like PHP Code Sniffer, PHP parallel Lint. I spend the majority of my time on CLI tools, and only a small portion of my time consulting on the things for WordPress, like keeping that cross version compatible. Derick Rethans 1:12 All right, very well. I actually did not know that. So I learned something new already. Juliette Reinders Folmer 1:16 Yeah, but it's nice. You give me the chance now to correct that image. Because I notice a lot of people see me in within the PHP world as the voice of WordPress and vice versa, by the way in WordPress world to see me as far as PHP. And in reality, I do completely different things. There is a perception bias there somewhere and which has slipped in. Derick Rethans 1:38 It's good to clear that up then. Juliette Reinders Folmer 1:39 Yeah, thank you. Derick Rethans 1:40 Let's have a chat about the RFC itself then. What is the problem that is RFC is trying to solve? Juliette Reinders Folmer 1:46 There was an RFC or 8.2 which has already been approved in October, which deprecates partially supported callables. Now for those people listening who do not know enough about that RFC, partially supported callables are callables which you can call via a function like call_user_func that which you can't assign to variable and then call as a variable. Sometimes you can call them just by using the syntax which you used for defining the callable, so not as variable but as the actual literal. Derick Rethans 2:20 And as an example here, that is, for example, static colon colon function name, for example. Juliette Reinders Folmer 2:26 Absolutely, yeah. Derick Rethans 2:27 Which you can use with call_user_func by having two array elements. You can call it with literal syntax, but you can't assign it to a variable and then call it. Do I get that, right? Juliette Reinders Folmer 2:36 Absolutely. That's it. There's eight of those. A

PHP Internals News: Episode 100: Sealed Classes London, UK Thursday, March 24th 2022, 09:04 GMT In this episode of "PHP Internals News" I talk with Saif Eddin Gmati (Website, Twitter, GitHub) about the "Sealed Classes" RFC that he has proposed. The RSS feed for this podcast is https://derickrethans.nl/feed-phpinternalsnews.xml, you can download this episode's MP3 file, and it's available on Spotify and iTunes. There is a dedicated website: https://phpinternals.news Transcript Derick Rethans 0:14 Hi, I'm Derick. Welcome to PHP internals news, the podcast dedicated to explaining the latest developments in the PHP language. This is episode 100. Today I'm talking with Saif Eddin Gmati about the sealed classes RFC that they're proposing. Saif, would you please introduce yourself? Saif Eddin Gmati 0:31 Hello, my name is Saif Eddin Gmati. I work as a Senior programmer at Les-Tilleuls.coop. I'm an open source enthusiast and contributor. Derick Rethans 0:39 Let's dive straight into this RFC. What is the problem that you're trying to solve with it? Saif Eddin Gmati 0:43 Sealed classes just like enums and tagged unions allow developers to define their data models in a way where invalid state becomes less likely. It also eliminates the need to handle unknown subtypes for a specific model, as using sealed classes to define models gives us an idea on what child types would be available at run time. Sealing also provides us with a way for restricting inheritance or the use of a specific trait. For example, if we look at logger trait from the PSR log package that could be sealed to logger interface. This way, we ensure that every use of this trait is coming from a logger not from any other class. Derick Rethans 1:24 I'm just reading through this RFC tomorrow, again, and something I didn't pick up on reading to it last time. It states that PHP already has sort of two sealed classes. Unknown Speaker 1:35 Yes, the throwable class in PHP can only be implemented by extending either error or exception. The same applies for DateTime interface, which can only be implemented by extending DateTime class or DateTime Immutable class. Derick Rethans 1:52 Because PHP itself doesn't allow you to implement either throwable or DateTimeInterface. I haven't quite realized that that these are also sealed classes really. What is sort of the motivation behind wanting to introduce sealed classes? Unknown Speaker 2:06 The main motivation for this feature comes from Hack the programming language. Hack contains a lot of interesting type concepts that I think personally, PHP could benefit from and sealed classes is one of those concepts. Derick Rethans 2:18 What kind of syntax are you proposing? Saif Eddin Gmati 2:21 The syntax I'm proposing actually there is three syntax options for the RFC currently, but the main syntax is inspired by both Hack and Java. It's more similar to the syntax used in Java as Hack uses attributes. Personally, I have been I guess, using attributes from the start as I personally see sealing and finalizing similar as both effects how inheritance work for a specific class. Having sealed implemented as an attribute while final uses a keyword brings more inconsistency into the language which is why I have decided not to include attributes as a syntax option. Derick Rethans 2:56 In my opinion, attributes shouldn't be used for any kind of syntax things. What they shoul

PHP Internals News: Episode 99: Allow Null and False as Standalone Types London, UK Thursday, March 10th 2022, 09:04 GMT In this episode of "PHP Internals News" I talk with George Peter Banyard (Website, Twitter, GitHub, GitLab) about the "Allow Null and False as Standalone Types" RFC that he has proposed. The RSS feed for this podcast is https://derickrethans.nl/feed-phpinternalsnews.xml, you can download this episode's MP3 file, and it's available on Spotify and iTunes. There is a dedicated website: https://phpinternals.news Transcript Derick Rethans 0:15 Hi, I'm Derick. Welcome to PHP internals news, a podcast dedicated to explain the latest developments in the PHP language. This is episode 99. Today I'm talking with George Peter Banyard, about the Allow null and false at standalone types RFC that he's proposing. Hello, George Peter, would you please introduce yourself? George Peter Banyard 0:36 Hello, my name is George Peter Banyard. I work on the PHP language, and I'm an Imperial student in maths in my free time. Derick Rethans 0:44 Are you're trying to say you're a student in your free time or contribute to PHP in your free time? George Peter Banyard 0:49 I feel like at this time, it's like, both are true at the same time. Derick Rethans 0:53 Let's hop into this RFC. It is titled allow null and false as standalone types. What is the problem that it is trying to solve? George Peter Banyard 1:02 This is the second iteration of this RFC. So the first one was to just allow null initially, and null is the unit type In type theory parlance of PHP, ie the type which only has one value. So null is a type and a value. And the main issue is that when for leads more with like inhabitants, and like the Liskov substitution principle. If you have like a method, like the parent method, which can be told like either null or an object, and your implementation in a child class always returns null, for various reasons, maybe because it doesn't support this feature, or whatever is out, or... If your child method only returns null, currently, you can't document, that you can't type this properly, you can document it in a doc comment or something like that. But due to how PHP type handling works, you need to specify at least like another type with null in the union. Basically resort to always saying like mimicking the parent signature, when you could be more specific. This was the main use case I initially went into. Derick Rethans 2:08 If I understand correctly, you can't just have an inherited method that has hinted as to just return null? George Peter Banyard 2:14 Exactly. If you always return null, maybe because you always work or something like that, then you must still declare the return type as like null or exception, which is not a concrete because you say what, like why never fail. And like static analysers, if they can figure it out that you're using a child class, they can't maybe like do some assumptions or work further down that like what you're doing is redundant or things like that. So that's one of the main reasons I initially went with it. And I didn't add false initially, because it was like, well, false, it's not really a type properly. It's, it's what's called a value type. False is one value from the Boolean type. And I was like, Well, okay, we're just going to limit it to like, being the type theory purist, limited to proper types, where null is a proper type, although it's a bit sometimes misunderstood, I feel in the PHP community at large. And then people were like, well, if

PHP Internals News: Episode 98: Deprecating utf8_encode and utf8_decode London, UK Thursday, March 3rd 2022, 09:02 GMT In this episode of "PHP Internals News" I chat with Rowan Tommins (GitHub, Website, Twitter) about the "Deprecate and Remove utf8_encode and utf8_decode" RFC. The RSS feed for this podcast is https://derickrethans.nl/feed-phpinternalsnews.xml, you can download this episode's MP3 file, and it's available on Spotify and iTunes. There is a dedicated website: https://phpinternals.news Transcript Derick Rethans 0:14 Hi, I'm Derick. Welcome to PHP Internals News, a podcast dedicated to explaining the latest developments in the PHP language. This is episode 98. Today I'm talking with Rowan Tommins about the "Deprecate and remove UTF8_encode and UTF8_decode" RFC that he's proposing. Hi, Rowan, would you please introduce yourself? Rowan Tommins 0:38 Hi, I'm Rowan Tommins. I'm a PHP software architect by day and try and contribute back to the community and have been hanging around in the internals mailing list for about 10 years and contributed to make the language better, where I can. Derick Rethans 0:57 Excellent. Yeah, that's how I started out as well, many, many more years before that, to be honest. This RFC, what problem is this trying to solve? Rowan Tommins 1:08 PHP has these two functions, utf8_encode and utf8_decode, which, in themselves, they're not broken. They do what they are designed to do. But they are very frequently misunderstood. Mostly because of their name. And because Character Encodings in general, are not very well understood. People use them wrong, and end up getting in all sorts of pickles that are worse than if the functions weren't there in first place. Derick Rethans 1:37 What are you proposing with the RFC then? Rowan Tommins 1:39 Fundamentally, I'm proposing to remove the functions. As of PHP 8.2, there will be a deprecation notice whenever you use them, and then in 9.0, they would be gone forever, and you wouldn't be able to use them by mistake, because they just wouldn't be there. Derick Rethans 1:56 I reckon there's going to be a way to actually do what people originally intended to do with it at some point, right? Rowan Tommins 2:02 So yeah, there are alternatives to these functions, which are much clearer in what you're doing, and much more flexible in what you can do with them so that they cover the cases that these functions sound like they're going to do, but don't actually do when you understand what they're really doing. Derick Rethans 2:20 I think we'll get back to that a little bit later on. You're wanting to deprecate these functions. But what do these functions actually do? Rowan Tommins 2:27 What they actually do is convert between a character encoding called Latin-1, ISO 8859-1, and UTF-8. So utf8_encode converts from Latin-1 into UTF-8, utf8_decode does the opposite. And that's all they do. Their names make it sound like they're some kind of fix all the UTF 8 things in my text. But they are actually just these one very specific conversion, which is occasionally useful, but not clear from their names. Derick Rethans 3:01 It's certainly how I have seen it used in the past, where people just throw everything and the kitchen sink at it, and expecting it to be valid UTF 8, and then at the end, decode. I mean, the decoding was not even part much of this, right? It's just throw everything at it, and t

PHP Internals News: Episode 97: Redacting Parameters London, UK Thursday, January 27th 2022, 09:09 GMT In this episode of "PHP Internals News" I chat with Tim Düsterhus (GitHub) about the "Redacting Parameters in Back Traces" RFC. The RSS feed for this podcast is https://derickrethans.nl/feed-phpinternalsnews.xml, you can download this episode's MP3 file, and it's available on Spotify and iTunes. There is a dedicated website: https://phpinternals.news Transcript Derick Rethans 0:00 Before we start with this episode, I want to apologize for the bad audio quality. Instead of using my nice mic I managed to use to one built into my computer. I hope you'll still enjoy the episode. Derick Rethans 0:30 Hi, I'm Derick. Welcome to PHP internals news, a podcast dedicated to explaining the latest developments in the PHP language. This is episode 97. Today I'm talking with Tim Düsterhus about Redacting Parameters in Backtraces RFC that he's proposing. Tim, would you please introduce yourself? Tim Düsterhus 0:50 Hi, Derick, thank you for inviting me. I am Tim Düsterhus, and I'm a developer at WoltLab. We are building a web application suite for you to build online communities. Derick Rethans 0:59 Thanks for coming on this morning. What is the problem that you're trying to solve with this RFC? Tim Düsterhus 1:05 If everything is going well, we don't need this RFC. But errors can and will happen and our application might encounter some exceptional situation, maybe some request to an external service fails. And so the application throws an error, this exception will bubble up a stack trace and either be caught, or go into a global exception handler. And then basically, in both cases, the exception will be logged into the error log. If it can be handled, we want to make the admin side aware of the issues so they can maybe fix their networking. If it is unable to be handled because of a programming error, we need to log it as well to fix the bug. In our case, we have the exception in the error log. And what happens next? In our case, we have many, many lay person administrators that run a community for their hobby, they're not really programmers with no technical expertise. And we also have a strong customers help customers environment. What do those customers do? They grab their error log and post it within our forums in public. Now in our forum, we have the error log with the full stack trace, including all sensitive values, maybe user passwords, if the Authentication Service failed, or something else, that should not really happen. In our case, it's lay person administrators. But I'm also seeing that experienced developers can make this mistake. I am triaging issues with an open source software written in C. And I've sometimes seeing system administrators posting their full core dump, including their TLS certificates there, and they don't really realize what they have just done. That's really an issue that affects laypersons, and professional administrators the same. In our case, our application attempts to strip those sensitive information from this backtrace. We have a custom exception handler that scans the full stack face, tries to match up class names and method names e.g. the PDO constructor to scrub the database password. And now recently, we have extended this stripping to also strip anything from parameters that are called password, secret, or something like that. That mostly works well. But in any case, this exception handler will miss sensitive information because it needs to basically guess what parameters are sensitive values and which don't. And also our exception handler grew very complex because to match up thos

PHP Internals News: Episode 96: User Defined Operator Overloads London, UK Thursday, December 16th 2021, 09:24 GMT In this episode of "PHP Internals News" I chat with Jordan LeDoux (GitHub) about the "User Defined Operator Overloads" RFC. The RSS feed for this podcast is https://derickrethans.nl/feed-phpinternalsnews.xml, you can download this episode's MP3 file, and it's available on Spotify and iTunes. There is a dedicated website: https://phpinternals.news Transcript Derick Rethans 0:14 Hi, I'm Derick. Welcome to PHP internals news, a podcast dedicated to explaining the latest developments in the PHP language. This is episode 96. Today I'm talking with Jordan, about a user defined operator overloads RFC that he's proposing. Jordan, would you please introduce yourself? Jordan LeDoux 0:33 My name is Jordan LeDoux. I've been working in PHP for quite a while now. This is the second time I have ventured to propose an RFC. Derick Rethans 0:44 What was the first one? Jordan LeDoux 0:45 The first one was the "never for parameter types", which was much more exploratory. And we talked about it a little bit. And it generated a lot of good discussion that contributed to kind of the idea formation, which was what I hope to get out of it. Derick Rethans 1:01 Okay, but that didn't end up making it into a PHP release. As far as I understand, right? Jordan LeDoux 1:07 No, I withdrew it actually, it was clear that the better way to approach the problem it was trying to solve was with a much more comprehensive solution. That particular solution was something that only required a seven line change to the engine. So I wanted to see if it was something people were okay with, or thought was a decent idea for that particular problem, much more comprehensive, like template classes, or something like that is probably the better route to go. Derick Rethans 1:35 Well, I think the RFC that we're talking about today, is going to require quite a bit more than seven lines of code? Jordan LeDoux 1:41 Quite a bit more. Yeah. Derick Rethans 1:42 So what is this RFC that we're talking about today? Jordan LeDoux 1:45 Well, user defined operator overloads is a way for PHP developers to define the ways in which objects interact with specific operators. So for instance, the plus operator, the plus sign. It's a way for those objects to kind of define their own logic as far as how that's handled, which right now, as of PHP 8.0, those were all switched to type errors. So it's not possible currently to write any code that doesn't result in a fatal error, where objects are used with operators. Derick Rethans 2:25 Usually, I ask about every RFC, what problem are you trying to solve this? So what problem are you trying to solve this RFC? Jordan LeDoux 2:31 The biggest problem that this solves is that objects contain, so objects in most programs represent a value or multiple values that have a program context. That's the most powerful thing about objects is they're contextual, and they understand the state, they understand what state the object is in, and sometimes even what state the whole program is in. And that's necessary for a lot of things. Like for instance, if you're tracking a distance, you know, you might measure that meters, and that would have a number you might have 30 meters of distance, but it also has a unit of meters. You could j

PHP Internals News: Episode 95: PHP 8.1 Celebrations London, UK Thursday, November 25th 2021, 09:23 GMT In this episode of "PHP Internals News" we're looking back at all the RFCs that we discussed on this podcast for PHP 8.1. In their own words, the RFC authors explain what these features are, with your host interjecting his own comments on the state of affairs. The RSS feed for this podcast is https://derickrethans.nl/feed-phpinternalsnews.xml, you can download this episode's MP3 file, and it's available on Spotify and iTunes. There is a dedicated website: https://phpinternals.news Transcript Derick Rethans 0:14 Hi, I'm Derick, and this is PHP internals news, a weekly podcast dedicated to demystifying the development of the PHP language. Derick Rethans 0:23 This is episode 95. I've been absent on the podcast for the last few months due to other commitments. It takes approximately four hours to make each episode. And I can now unfortunately not really justify spending the time to work on it. I have yet to decide whether I will continue with it next year to bring you all the exciting development news for PHP 8.2. Derick Rethans 0:44 However, back to today, PHP eight one is going to be released today, November 25. In this episode, I'll look back at the previous episodes this year to highlight a new features that are being introduced in PHP 8.1. I am not revisiting the proposals that did not end up making it into PHP 8.1 feature two features I will let my original interview speak. I think you will hear Nikita Popov a lot as he's been so prolific, proposing and implementing many of the features of this new release. However, in the first episode of the year, I spoke with Larry about enumerations, which he was proposing together with Ilija Tovilo. I asked him what enumerations are. Larry Garfield 1:26 Enumerations, or enums, are a feature of a lot of programming languages. What they look like varies a lot depending on the language, but the basic concept is creating a type that has a fixed finite set of possible values. The classic example is booleans. Boolean is a type that has two and only two possible values true and false. Enumerations are way to let you define your own types like that, to say this type has two values Sort Ascending or Sort Descending. This type has four values for the four different card suits, and a standard card deck. Or a user can be in one of four states pending, approved, cancelled or active. And so those are the four possible values that this variable type can have. What that looks like varies widely depending on the language. In a language like C or C++, it's just a thin layer on top of integer constants, which means they get compiled away to introduce at compile time, and they don't actually do all that much they're a little bit to help for reading. On the other end of the spectrum, you have languages like rust or Swift, where enumerations are a robust, advanced data type and data construct of their own. That also supports algebraic data types. We'll get into that a bit more later. And is a core part of how a lot of the system actually works in practice, and a lot of other languages are somewhere in the middle. Our goal with this RFC is to give PHP more towards the advanced end of enumerations. Because there are perfectly good use cases for it, so let's not cheap out on it. Derick Rethans 3:14 In the next episode, I spoke with Aaron Piotrowski about another big new feature: fibres. Aaron Piotrowski 3:20 A few other languages already have Fibers like Ruby. And they're sort of similar to threads in that they contain a separate call stack and a separate

PHP Internals News: Episode 94: Unwrap Reference After Foreach London, UK Thursday, August 26th 2021, 09:22 BST In this episode of "PHP Internals News" I chat with Nikita Popov (Twitter, GitHub, Website) about the "First Class Callable Syntax" RFC. The RSS feed for this podcast is https://derickrethans.nl/feed-phpinternalsnews.xml, you can download this episode's MP3 file, and it's available on Spotify and iTunes. There is a dedicated website: https://phpinternals.news Transcript Derick Rethans 0:14 Hi, I'm Derick. Welcome to PHP internals news, the podcast dedicated to explaining the latest developments in the PHP language. This is Episode 94. Today I'm talking with Nikita Popov about the unwrap reference after foreach RFC that he's proposing. Nikita, would you please introduce yourself? Nikita Popov 0:33 Hi, Derick. I'm Nikita and I work at JetBrains on PHP core development. Derick Rethans 0:38 So no changes compared to the last time. Nikita Popov 0:41 Yes, at the time before that. Derick Rethans 0:43 So what is the problem that is RFC is going to solve? Nikita Popov 0:46 Well, it's really a very minor thing. I think it's a relatively well known problem for the more experienced PHP programmers. It's like a classic example, you have a foreach loop by reference. So foreach array as value by reference, and then you do a second loop after that, foreach array as value at the same it's by value. So without the reference sign. The result of that is that your last two array elements are going to be the same, which is kind of unexpected. If you're not familiar with how references in PHP work and scoping in PHP works. So I think it's worth explaining what's going on there. Derick Rethans 1:27 Can you quickly explain the scoping or rather the lack of it, I suppose? Nikita Popov 1:31 Yeah, it's really the lack of PHP really only has function scoping. So if you have a foreach array as value, then the value variable is going to stay alive, even after the foreach loop. And usually, that won't make much of a difference. So you will just have like reference to the last element of the array, might even be useful for some cases, you know, before we added the array, I think, array_key_last function. If the last element now is a reference, so if you have a reference to the last element, then you're write into that variable is also going to modify the last element of the array. So if you now have a second foreach loop, using the same variable, that's actually not just modifying that variable, but it's also always modifying the last element of the array. Derick Rethans 2:15 Okay, just to clarify, it isn't necessarily the last element in the foreach loop. It's the last one that's been assigned to? Nikita Popov 2:22 Yeah, that's, that's true. Derick Rethans 2:24 Is this not something that people actually use for some useful reasons? Nikita Popov 2:28 As mentioned before, technically, you could use it to get a reference to the last element and then modify the last element outside the foreach loop. I don't think this is a particularly common use case. But I'm sure people have used in here there. This is a use case we would break with the proposed RFC. Derick Rethans 2:47 I think it is one I have used in the past, it's probably not how I would do it now. But I'm pretty sure I have s

PHP Internals News: Episode 93: Never For Parameter Types London, UK Thursday, August 19th 2021, 09:21 BST In this episode of "PHP Internals News" I chat with Jordan LeDoux (GitHub) about the "Never For Parameter Types" RFC. The RSS feed for this podcast is https://derickrethans.nl/feed-phpinternalsnews.xml, you can download this episode's MP3 file, and it's available on Spotify and iTunes. There is a dedicated website: https://phpinternals.news Transcript Derick Rethans 0:14 Hi, I'm Derick. Welcome to PHP internals news, a podcast dedicated to explaining the latest developments in the PHP language. This is Episode 93. It's been quiet over the last month, so it didn't really have a chance to talk about upcoming RFCs mostly because there were none. However, PHP eight one's feature freeze has happened now, a new RFCs are being targeted for the next version of PHP eight two. Today I'm talking with Jordan LeDoux, about the Never For Parameter Types RFC, the first one targeting this upcoming PHP version. Jordan, would you please introduce yourself? Jordan LeDoux 0:50 Certainly. And thanks for having me. My name is Jordan. I've worked as a developer for about 15 years now. Most of my career has been spent working in PHP. Although professionally, I've had experience working in C#, Python, TypeScript, mostly in the form of JavaScript, but a little bit of Node and, you know, a variety of other languages that I haven't spent enough time in to really be proficient in any real way. But recently, I decided to do something that I have thought about doing for many years, but never actually jumped into which is exploring the PHP engine itself and how I could possibly contribute to it. Derick Rethans 1:32 And here we are, but your first our thing. Jordan LeDoux 1:35 Yeah, it's exciting. Derick Rethans 1:36 What is this RFC about, what does it propose? Jordan LeDoux 1:39 Well, this RFC proposes allowing the never type, which was added in 8.1 as a return value, to parameters for functions and methods on objects. The main idea behind that is that when never was proposed as a return type, it was meant to signal that the function would never return. Not that it returns void, which of course, void signifies which is returning no value or returning, returning without any specified information. And never return signifies that the function will never return, which is a concept that exists in many other languages. And for that purpose in other languages, what's usually used is something called a bottom type. And that's what never ended up being. And I'm proposing that we extend the use of that bottom type to other areas where the type may be helpful. Derick Rethans 2:38 So a bottom type, that might be a new term for many people, it will certainly for me when I looked at the never RFC for as return types. Can you sort of explain what a bottom type is, especially thinking about object oriented theory with something that we'd like to call the Liskov Substitution Principle? And also, how does it apply to argument types? Jordan LeDoux 2:59 Let's start with the Liskov Substitution. The general idea behind Liskov Substitution is that if A is a subtype of B, then anywhere that A exists, you should be able to substitute B. It has to do with when you have a class hierarchy in in an object oriented language, that that class hierarchy guarantees certain things about substitutionality, like whether or not something can be substituted for something else. That affects language design in ways that a lot of programmers are ki

PHP Internals News: Episode 92: First Class Callable Syntax London, UK Thursday, July 22nd 2021, 09:20 BST In this episode of "PHP Internals News" I chat with Nikita Popov (Twitter, GitHub, Website) about the "First Class Callable Syntax" RFC. The RSS feed for this podcast is https://derickrethans.nl/feed-phpinternalsnews.xml, you can download this episode's MP3 file, and it's available on Spotify and iTunes. There is a dedicated website: https://phpinternals.news Transcript Derick Rethans 0:14 Hi, I'm Derick. Welcome to PHP internals news, the podcast dedicated to explaining the latest developments in the PHP language. This is Episode 92. Today I'm talking with Nikita Popov about a first class callable syntax RFC that he's proposing together with Joe Watkins. Nikita, would you please introduce yourself? Nikita Popov 0:36 Hi, Derick. I'm Nikita and I am still working at JetBrains. And still working on PHP core development. Derick Rethans 0:43 Just like about half an hour ago when we recorded an earlier episode. Nikita Popov 0:47 Exactly. Derick Rethans 0:48 This RFC has no relation to read only properties. What is the first class callable syntax RFC about? Nikita Popov 0:55 The context here is that PHP has the callable syntax based on literals, which is that if you just use a plain string, it's interpreted as a function name, and an array where the first element is an object, and the second one is a method name, that's methods. Or the first element is the class name, and the second one is method name, that's a static method. Derick Rethans 1:17 I would consider this concept a bit of a hack, especially the the one with the arrays, and I reckon you feel similar and hence this RFC? Nikita Popov 1:27 Yes, I do. So the current callable syntax has a couple of issues. I think the core issue is that it's not really analysable. So if you see this kind of like array with two strings inside it, it could just be an array with two strings, you don't know if that's supposed to actually be a static method reference. If you look at the context of where it is used, you might be able to figure out that actually, this is a callable. And like in your IDE, if you rename this method, then this array should also be this array element will also be renamed. But there's like a lot of complex reasoning that the static analyser has to perform. That's one side of the issue. The second one is that callables are not scope independent. For example, if you have a private method, then like at the point where you create your callable, like as an array, it might be callable there, but then you pass it to some other function. And that's in a different scope. And suddenly that method is not callable there. So this is a general issue with both like this callable syntax based on arrays, and also the callable type. It's a callable at exactly this point, not callable at a later point. This is what the new syntax essentially addresses. So it provides a syntax that like clearly indicates that yes, this really is a callable, and it performs the callable callability check at the point where it's created, and also binds the scope at that time. So if you pass it to a different function in a different scope, it still remains callable. Derick Rethans 3:01 And it's guaranteed to always be callable. Nikita Popov 3:03 Yeah, exactly. Derick Rethans 3:04 What does the syntax like?