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Re: Hash key string restrictions?[THANKS]

by Ojosh!ro (Beadle)
on Feb 10, 2007 at 01:17 UTC ( [id://599314]=note: print w/replies, xml ) Need Help??


in reply to Hash key string restrictions?

Thank you all very much. This is the answer I hoped for.
As to the purpose of the question:
I was experimenting with eval and wondered if I could put sub-references in a hash to prevent double evals.
(the mechanism behind it would check the existence of the to-be-evalled string and simply return a reference to the sub-ref in question if it existed and otherwise make a new pair )

I have no clue of whether such a mechanism already exists under perl's shiny bonnet.

  • Comment on Re: Hash key string restrictions?[THANKS]

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Re^2: Hash key string restrictions?[THANKS]
by ikegami (Patriarch) on Feb 10, 2007 at 04:18 UTC
    Yup! Assuming the evaled code returns a code ref, 
    my $code_ref = $code_cache{$code} ||= eval $code;
die("Unable to compile and run code: $@\n)"
   if !$code_ref;
$code_ref->();

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      That was the basic idea,
      ( the ||= eval $code part would also be stored in the %code_cache )
[reply]
        The statement I provided *does* store the result in %code_cache. Note the usage of ||= instead of ||.
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