`when {}` is a syntax error about method-signatures HOT 7 CLOSED

OIC it thinks its a block. Patch on the way.

from method-signatures.

Hrm. I can special case an empty hash, but what about hashes in general? I don't think there will be much call for checking for anything but an empty hash, so I'm inclined to just special case it. Anything more complicated can be done as a full block.

from method-signatures.

Hashes in general are already supported.

PPI uses the usual perlish guesswork to determine
whether a pair of curlies are a hash or a block.

Empty curlies are arguably a useless special case
as an empty hash will never smartmatch anything.

Of course, treating {} as an empty block would be
equally useless, so special casing them as empty
hash is probably for the best (i.e. least surprising).

from method-signatures.

Well, we should probably special-case it as whatever-doesn't-generate-a-syntax-error. :-D

This fix will go into the next dev release. Just waiting now for CPANTesters to throw up some reports for me to look at ...

from method-signatures.

@thoughtstream PPI might have that guesswork, but inject_for_sig() isn't using it. It's using a regex. I'll look at switching it to PPI, but this fix to the existing regex should go in.

And an empty hash ref smart matches, surprise, an empty hash ref.

perl -wle '$h = {};  print $h ~~ {} ? "Match" : "No Match" '
Match

perl -wle '$h = { foo => 23 };  print $h ~~ {} ? "Match" : "No Match" '
No Match

This is handy for providing a default if the user passes in an empty hash ref, similar to using when "" for a string parameter.

from method-signatures.

Very good point re empty hashref matching empty hashes.
This definitely should be special-cased.

from method-signatures.

Fixed in version 20121201.

from method-signatures.