On Wed, Jun 30, 2021, at 8:59 AM, Olle Härstedt wrote: > > I've been pondering if a completely different approach with a prefix > > symbol would be able to be less complex, and the simple answer is I > > have absolutely no idea. But we are running low on symbols... > > Ah, I found the technical details that Joe gave me (right after I hit > send, of course). Quoting Joe: > > "the engine expects certain things to happen, and is designed and then > optimized around those assumptions ... for example, a stream of INIT, > SEND, DO_FCALL is not meant to be interrupted, the first fundamental > change you have to make is making the engine aware that stream of INIT, > SEND, + are not always followed by DO_FCALL " > > So yes, it sounds like hooking into the function call process is where > the complexity comes from. Which suggests that an approach that works > using a different syntax that desugars to a closure would avoid that > issue, but then we need a syntax that wouldn't be ambiguous, and that's > getting harder and harder to find. (Nikita's first-class-callables RFC > notes some of the issues with available symbols, and they're > essentially the same for partials either way.) And I've been told that > creating closures in the AST compiler is Hard(tm)... > > --Larry Garfield > > > Wrapping stuff in lambdas is otherwise the obvious solution, no? Make > `strlen(?)` evaluate to `fn ($x) => strlen($x)`. Does it depend on the > level of look-ahead in the compiler why it's so hard? Didn't work much > with scripting language internals. > > Olle
The tricky part is that conversion has to happen entirely at runtime, because we need the type information from the function being partialed, and at that point creating an actual closure is, apparently, rather hard. It cannot be done up at the AST level where it would be conceptually much easier. We've been discussing this for the past several days in chat, and the basic conclusion is that the PHP engine does not offer any easy way to do this. It's one hard-and-messy approach or another hard-and-messy approach. So far no one has figured out a not hard-and-messy way to make it work, regardless of performance. --Larry Garfield -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: https://www.php.net/unsub.php
