Re: [RFC] Pre-draft for PipeOp v2

On 28/09/2017 20:07, Levi Morrison wrote:

The brace style is concise, nicely delimits the expression, and seems the clearest for me to read because the symbols don't dominate.

This is something that I tried to push for in previous discussions - I've never liked the syntaxes where the expression floats away from the operator, and you have to work out where it ends. The counter-argument I got was that some people actually like writing things like this, although I'm not entirely clear why: fn($x) => fn($y) => in_array($x, $y) Which brings us to the question of how we might generalise the {} syntax for more complex situations. Clearly, we can't just nest them if the first parameter is always called $0: { { in_array($0, $0) } }  #WAT? Obviously named variables are kind of useful anyway, so maybe $0 could be the default, but allow them to be specified: // Simple definition { $0 . ' world' } == { $greeting => $greeting . ' world' ) // Nested definitions { $x => { in_array($x, $0) } } == { $x => { $y => in_array($x, $y) } } // 2-parameter function { $x, $y => in_array($x, $y) }

My impression from the community is that the pipe operator is desirable but

not if it encourages string or array callables.

Yeah, my first thought on this thread that I liked this version of the proposal significantly less than the previous one, because I always liked the idea of this being a programming style, with the RHS being a statement to be rewritten. So you could write $input |> $foo = $$ |> echo $$ |> return $$ ... But with a suitable way of creating a callable to pass to it, I could live with it. What if the syntax for taking a reference to function was just a special case of the partial application / lambda syntax? At risk of turning into Perl, we could use "$..." to mean "copy in all the parameters": $foo = { in_array($...) }; This would be logically equivalent to: $foo = function(...$x) { return in_array(...$x); } But the compiler could actually optimise it as something more like Closure::fromCallable('in_array') Just throwing some thoughts out there to see if any of them stick... -- Rowan Collins [IMSoP]