Re: Re: [RFC] Arrow functions / short closures

On Sun, Apr 14, 2019, at 11:52 AM, Nikita Popov wrote: > So, there's been quite a bit of extra discussion here... unfortunately I > can't say that it really clarified anything, we're still circling around > different syntax choices, with the main contenders being fn, \ and ==>. > > fn($x) => $x > fn($x, $y) => $x*$y > > \$x => $x > \($x, $y) => $x*$y > > $x ==> $x > ($x, $y) ==> $x*$y > > I think the main qualities of these possibilities are: > > * Implementation complexity: fn and \ are easy, ==> is hard (lexer hack). > * Availability of reduced syntax: \ an ==> have a special single-argument > syntax, fn doesn't. > * Obviousness/readability: fn and ==> are obvious, while \ is not. > Especially \$x => $x looks quite obscure to the uninitiated (is that a > variable escape, like it would be in strings?) > > At this point I'm considering to either a) move forward with fn() as the > choice I'd consider most likely to gather a consensus or b) have a > secondary three-way vote between these three syntax choices. > > Nikita I was under the impression from your earlier comments that ==> made the lexer too unhappy to even consider. Is that not the case? From a usability POV, I think ==> has the edge; it's reasonably self-documenting and has a short-circuit version that is still highly readable and not confusing. It also fits the "think of it as an expression not a function call" mindset, which is important. The only downside is the implementation complexity. I think you have final call on whether that would be too-ugly implementation-wise. If it doesn't make the lexer too unhappy ==> is my preference, I think. \$x I'd probably get used to, even if it is a bit ugly. fn() is the "safe" option: Most verbose but keeps the lexer happy. --Larry Garfield