Hi! proposed syntax:
> $gen = [for $list as $x if $x % 2 yield $x*2];
>
current php + short closures:
$gen = () => foreach($list as $x) if($x % 2) yield $x * 2;
1- parentheses could be optional around control structures, so `if(true){}`
could be simply `if true{}`
2- "for" could accept the syntax of "foreach"
3- we need short closures
