How is the xx operator in Raku able to delay the evaluation of its left-hand side code operand?

Question

The 'xx' operator is interesting in that this:

(^100).pick xx 10

produces a list of 10 random Int's rather than one random Int repeated 10 times as a list.

Is the operator handled as a special case by the compiler? Or is it really just another sub that we can define ourselves too? (If so, I'd be very interested to know how...)

Thanks

Answer 1

Yes, this is one of a range of operators that currently exist as special forms in the compiler. Other examples include || and &&, which only evaluate the right hand side depending on the boolification of the left hand side.

At present, there's not a way to define such an operator yourself (or at least, not an officially supported one; if prepared to tinker in compiler internals all things are possible). However, macros - planned for the next major Raku language version - will enable this.