in reply to Re: Bloated code of loops and conditionals
in thread Bloated code of loops and conditionals

Thanks tlm (the artist formerly known as PP). It looks brilliant, but a bit beyond my experience. I have a couple of questions.

- in the line: 

next unless exists $goal { $g }

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should $goal be goals with an 's'?

- not sure what is going on with the 'hash slice assignment' line

I'll plug this into my code, but I just wanted to understand it at the same time.


—Brad
"The important work of moving the world forward does not wait to be done by perfect men." George Eliot

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Re^3: Bloated code of loops and conditionals
by tlm (Prior) on Apr 23, 2005 at 00:31 UTC

    Regarding your first question, yes, that was a typo (now fixed).

    A hash slice is a way to access several values of a hash using a list of keys. For regular hashes, for example, 

    @hash{ qw( foo bar baz ) } = ( 1, 2, 3 );

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    has the same effect as 
    $hash{ foo } = 1;
$hash{ bar } = 2;
$hash{ baz } = 3;

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    You can use slices to copy several values from one hash to another. E.g. 
    @keys = qw( foo bar baz );
@copy{ @keys } = @orig{ @keys };

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    The last line copies three key-value pairs from %orig to %copy. In the code I posted earlier, the only difference is that the accessing of the RHS slice is done via a reference ($d) to a hash instead of a regular hash: 
    @h{ @flds } = @{ $d }{ @flds };  # hash slice assignment

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    Once you dereference a hash ref you can use it like any other hash.

    Slices are discussed in perldata, and using references in perlreftut and perlref.

    the lowliest monk

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