To Raku - The BQN List Operator

BQNListOp.md

The BQN list operator ‿ can readily transfer into Raku. It's basically the same as Raku's list operator: ,. There is a small devil in the detail and that can be illustrated in the following example:

multi sub infix:<‿> ($a, $b) { 
  infix:<,>($a, $b) 
}

say 1‿2‿3; # ((1 2) 3)

An easy thought as to a solution would be to flatten the result of the infix operation, but that would be incorrect. The trick is to flatten only when the LHS is a List. So a better version of the above operation is as follows:

# Can't use SmartMatch because Array ~~ List is True!
multi sub infix:<‿> ($a, $b) { 
  infix:<,>($a.WHAT === List ?? |$a !! $a, $b) 
}

say 1‿2‿3   # (1 2 3)
say [1‿2]‿3 # ([1 2] 3)

Would be interested in hearing from some of the BQN coders out there if this works for them.

say [1‿2]‿3 # ((1 2) 3 should be say [1‿2]‿3 # ([1 2] 3).

Ah... good point. Thanks.

This seems to do the trick.

sub infix:<‿>(|c) is assoc('list') {
    infix:<,>(|c)
}

say 1‿2‿3‿4‿5;   # (1 2 3 4 5)
say ((1‿2)‿3)‿4; # (((1 2) 3) 4)