# Inline Lambda Functions - Thread: https://externals.io/message/53653 - Original archive: https://news-web.php.net/php.internals/53653 - Started by Jarrod Nettles on 2011-06-29T12:36:38+00:00 - Messages: 4 - Reply by email to internals@lists.php.net - More for agents: search with https://externals.io/search.md?q={query} · JSON API at https://externals.io/api · documentation at https://externals.io/llms.txt --- ## #53653 — Jarrod Nettles — 2011-06-29T12:36:38+00:00 URL: https://externals.io/message/53653#53653 Hi Stefan, The point was not about array filtering or LINQ or any of that. It was about the plausibility of using a shorthand for closures. Instead of this..... array_filter($source, function($x){ return $x < 5; }); Being able to do this..... (or something like it). array_filter($source, $x => $x < 5); This would provide a much more friendly way of using callbacks. Lambdas have great uses, but I feel like they are underutilized in PHP. C#, for example, has made excellent use of a lambda-friendly syntax like the one above, and Java is planning something similar (for Java 8, I believe). From: Stefan Neufeind Date: June 28, 2011 2:20:39 PM CDT To: internals@lists.php.net Subject: Re: [PHP-DEV] Inline Lambda Functions > There are two projects that I've been following for awhile now: PLINQ > and PHPLinq. > http://plinq.codeplex.com/ > http://phplinq.codeplex.com/ > Both of them have made very solid attempts at providing LINQ-like > functionality to PHP but with both, I've been a little frustrated > with the implementations, due to the wordy syntax that PHP lambda > functions require. [...] Hi, well, for your examples: Why not just `array_filter()` with an appropriate callback? Should handle it like you describe plinq does it, right? Regards, Stefan --- ## #53657 — Martin Scotta — 2011-06-29T14:50:09+00:00 URL: https://externals.io/message/53653#53657 · In reply to: #53653 Wed, Jun 29, 2011 at 9:36 AM, Jarrod Nettles wrote: > Hi Stefan, > > The point was not about array filtering or LINQ or any of that. It was > about the plausibility of using a shorthand for closures. > > Instead of this..... > > array_filter($source, function($x){ return $x < 5; }); > > Being able to do this..... (or something like it). > > array_filter($source, $x => $x < 5); > > This would provide a much more friendly way of using callbacks. Lambdas > have great uses, but I feel like they are underutilized in PHP. C#, for > example, has made excellent use of a lambda-friendly syntax like the one > above, and Java is planning something similar (for Java 8, I believe). > > > From: Stefan Neufeind > Date: June 28, 2011 2:20:39 PM CDT > To: internals@lists.php.net > Subject: Re: [PHP-DEV] Inline Lambda Functions > > > > > […] > > [...] > > Hi, > > well, for your examples: Why not just `array_filter()` with an appropriate > callback? Should handle it like you describe plinq does it, right? > > > Jarrod I think is a very good idea. Which you think the syntax will be for... * multiples arguments * multiples sentences * no return value closures could be kind of wordy but they are very clear about those. Martin Scotta > Regards, > Stefan --- ## #53671 — John Crenshaw — 2011-06-29T17:03:24+00:00 URL: https://externals.io/message/53653#53671 · In reply to: #53653 > Instead of this..... > > array_filter($source, function($x){ return $x < 5; }); > > Being able to do this..... (or something like it). > > array_filter($source, $x => $x < 5); This really isn't clear. Deciphering the intent of the code requires looking at all the surrounding stuff, because it could mean something totally different in an array. In other words, // This would be a lambda array_filter($source, $x => $x < 5); // This would not array($source, $x => $x < 5); // and this would not call_user_func_array('array_filter', array($source, $x => $x < 5)); The fact that the syntax for an expression isn't portable in places where (so far) every other expression has been, is a serious concern. Additionally, the proposed syntax is unusable for functions with more than one line, making it similar in badness to if statements without braces. IMO the current syntax for inline functions is perfectly sufficient, even for the PLINQ example given earlier, and has massive advantages over this one in terms of readability, affordance, flexibility, and language clarity. John Crenshaw Priacta, Inc. --- ## #53673 — Anthony Ferrara — 2011-06-29T17:34:39+00:00 URL: https://externals.io/message/53653#53673 · In reply to: #53671 Well, we could take python's approach and use a syntax similar to this: array_filter($source, lambda $x: $x < 5); array_map($source, lambda $x, $y: $x < $y); However, I would question the need. Pythonic lambdas cannot contain anything but expressions. Therefore they cannot have any meaningful side effects. While this is good, it also raises the question as to the need for it. PHP has first-class anonymous functions, something which python does not (it has local functions, or lambdas, but no true anonymous function, every non-lambda has a name). So the need in PHP for a lambda style construct is greater than PHP's. And what's the gain for PHP? A few less characters to type? I'm not sure that readability is gained, compare: array_filter($array, function($element) { return $element < 5; }); and array_filter($array, lambda $element: $element < 5); I feel the first is more readable at a glance. Anthony > > > […] > > This really isn't clear. Deciphering the intent of the code requires looking at all the surrounding stuff, because it could mean something totally different in an array. In other words, > >    // This would be a lambda >    array_filter($source, $x => $x < 5); >    // This would not >    array($source, $x => $x < 5); >    // and this would not >    call_user_func_array('array_filter', array($source, $x => $x < 5)); > > The fact that the syntax for an expression isn't portable in places where (so far) every other expression has been, is a serious concern. > > Additionally, the proposed syntax is unusable for functions with more than one line, making it similar in badness to if statements without braces. IMO the current syntax for inline functions is perfectly sufficient, even for the PLINQ example given earlier, and has massive advantages over this one in terms of readability, affordance, flexibility, and language clarity. > > John Crenshaw > Priacta, Inc.