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Re^2: map syntax error -- weird

by McA (Priest)
on Mar 22, 2013 at 10:32 UTC ( #1024912=note: print w/replies, xml ) Need Help??

in reply to Re: map syntax error -- weird
in thread map syntax error -- weird

Rolf was faster with his answer than me. Allow one annotation: perldoc -f map has a paragraph explaining this ambiguity.


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Re^3: map syntax error -- weird
by LanX (Bishop) on Mar 22, 2013 at 10:39 UTC
    oops true! =)

                   "{" starts both hash references and blocks, so "map { ..."
                   could be either the start of map BLOCK LIST or map EXPR, LIST.
                   Because perl doesn’t look ahead for the closing "}" it has to
                   take a guess at which its dealing with based what it finds just
                   after the "{". Usually it gets it right, but if it doesn’t it
                   won’t realize something is wrong until it gets to the "}" and
                   encounters the missing (or unexpected) comma. The syntax error
                   will be reported close to the "}" but you’ll need to change
                   something near the "{" such as using a unary "+" to give perl
                   some help:

    Since PBP "map EXPR, LIST" fell completely out of my scope, but it explains why a hash-ref could even be considered valid here.

    Cheers Rolf

    ( addicted to the Perl Programming Language)

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