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Haven't used Perl since decades, $foo.=bar raised an eyebrow but I had a dawn of an idea what hell of a drug this is.

Turns out, yes: It's syntactic sugar for $foo=$foo.bar() method invocation. Ref: https://docs.perl6.org/language/operators#methodop_.=

I fucking love Perl for this kind of shit! It allows to write super short programs which you can very well read, even better then super verbose traditional OOP languages.




Even better than that, if you create a new infix operator:

    sub infix:<OP> ( $a, $b ) {…}
You get `OP=` for free:

    $x OP= $y; # $x = $x OP $y
That is because `=` is actually a meta operator. (It takes an infix operator as a sort-of argument.)

    $x [OP]= $y; # more explicit that `OP` is an argument to `=`
---

You could also just use a regular subroutine as if it was an infix operator:

    sub foo ( $a, $b ) {…}

    $x [&foo] $y; # foo( $x, $y )
So you can also use it with the `=` meta operator:

    $x [&foo]= $y; # $x = foo( $x, $y )


Some people demonize languages for adding syntactic suggar, but I think this is what can make them really great. It raises the language (perl6 in this case) to a meta programming level. In a similiar way people refer to LISP as a meta programming language (while there the "meta" stems from the powerful macro language which again is LISP). I love that.




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