Re: [RFC][Discuss] Arrow Functions

> On Feb 3, 2017, at 11:53 AM, Levi Morrison <levim@php.net> wrote: > > One more thing: I'd like to re-emphasize that the syntax that > JavaScript uses and the one that HHVM/Hack uses are ambiguous in the > current class of our grammar. The following will not work unless we > move to a more powerful grammar and parser class: > > (params) => expr > (params) ==> expr > > This is why an un-ambiguous prefix is necessary: the prefix breaks the > ambiguities. The syntax I have suggested in the RFC and the one I > suggested just now are not ambiguous because distinct prefixes: > > fn(params) => expr > |params| => expr > > I look forward to more discussion! > > -- > PHP Internals - PHP Runtime Development Mailing List > To unsubscribe, visit: http://www.php.net/unsub.php > <http://www.php.net/unsub.php> I personally prefer the |params| => expr syntax. I like the visual separation the syntax provides between auto-capturing, short closures and regular closures. It gives the impression that it should behave differently, rather than just being a shorter way of declaring a closure. Below are a couple of real-world single line closures using the proposed syntax: [1] Loop::defer(|| => ($this->when)($exception, $value)); [2] $this->watcher = Loop::delay($time, || => $this->resolve($value)); IMHO, the reduced boilerplate required makes it easier to discern what is happening. Regards, Aaron Piotrowski [1] https://github.com/amphp/amp/blob/master/lib/Coroutine.php#L45-L47 [2] https://github.com/amphp/amp/blob/master/lib/Pause.php#L21-L23