Re: explanation of constant syntax?

[meonkeys]

I understand that the bareword FOO inside the parens is similar to when it's inside @{[...]} because it causes the subroutine created by the constant pragma to be called rather than FOO to simply be used as a hash key.

Would you elucidate on why this happens or point me to the right perldoc to read on this subject?

[merlyn]

Well, just break it apart:

[ ... ]

creates an arrayref pointing to its contents, in this case FOO (not quoted, so we get the constant value). And then:

@{ ... }

dereferences the enclosed value as if it were an array reference. So essentially, this is the hard way to say:

( ... )

between the two of them, except that it also interpolates within a double-quoted string. That's how I stumbled across this in the first place: how to evaluate a value inside a double-quoted string. I wrote about it in a CLP posting early in the Perl5 days, and the meme stuck and is still being used in other places.