in reply to map problem

This is another instance of the problem that a pair of curlies can stand for an anonymous subroutine or a hash reference. You can disambiguate with a semicolon in the block: 

my %y = map {; "prefix_$_" => 1 } qw(a b c);

[download]

It's more of a design limitation than a bug in perl or in you :-)

Perl 6 - second systems done right

Replies are listed 'Best First'.
Re^2: map problem
by morgon (Priest) on Mar 09, 2012 at 11:01 UTC
    Ok, but why is it neccessary only in the second case?
[reply]

      The decision to parse an opening curly bracket as a block or a hash ref is really just a heuristic. When the parser sees a string quote, it decides in favor of the hash ref, whereas a variable makes it assume a block.

      Or put differently, the parser cheats as hell, and sometimes that backfires. But not always.

      Perl 6 - second systems done right
[reply]

In Section Seekers of Perl Wisdom