This is even documented in perlref: 
           Because curly brackets (braces) are used for several other 
+things
           including BLOCKs, you may occasionally have to disambiguate
+ braces
           at the beginning of a statement by putting a "+" or a "retu
+rn" in
           front so that Perl realizes the opening brace isn't startin
+g a
           BLOCK.  The economy and mnemonic value of using curlies is 
+deemed
           worth this occasional extra hassle.

           For example, if you wanted a function to make a new hash an
+d return
           a reference to it, you have these options:

               sub hashem {        { @_ } }   # silently wrong
               sub hashem {       +{ @_ } }   # ok
               sub hashem { return { @_ } }   # ok

           On the other hand, if you want the other meaning, you can d
+o this:

               sub showem {        { @_ } }   # ambiguous (currently o
+k, but may change)
               sub showem {       {; @_ } }   # ok
               sub showem { { return @_ } }   # ok

           The leading "+{" and "{;" always serve to disambiguate the 
+expres-
           sion to mean either the HASH reference, or the BLOCK.

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-- Randal L. Schwartz, Perl hacker
Be sure to read my standard disclaimer if this is a reply.

In reply to Re^3: map()'s BLOCK and deviations from othogonality... by merlyn
in thread map()'s BLOCK and deviations from othogonality... by blazar

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