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Re: What is the point of the & sigil for function refs?

by grinder (Bishop)
on Feb 04, 2005 at 13:28 UTC ( #428051=note: print w/replies, xml ) Need Help??


in reply to What is the point of the & / ampersand sigil for function refs?

Is there ever a scenario when it's preferrable to use the &

There is one dramatic difference that occurs when you call the function without a parameter list:

#! /usr/local/bin/perl -w use strict; sub inner { print " inner: $_\n" for @_; } sub outer { print "outer: $_\n" for @_; inner; print "\n"; } sub outer_amp { print "outer_amp: $_\n" for @_; &inner; print "\n"; } outer( qw/ vroon gukguk faba / ); outer_amp( qw/ foomp tweedle zachitty / ); __RESULTS__ outer: vroon outer: gukguk outer: faba outer_amp: foomp outer_amp: tweedle outer_amp: zachitty inner: foomp inner: tweedle inner: zachitty

When using the &inner variant, whatever remains of @_ in the calling routine is passed to the called routine. The only time it's really useful is when doing out-of-the-ordinary stuff like autoloading. In general you should avoid it. It leads to bad surprises

PS: metasyntactic function call arguments courtesy of BooK's Acme::MetaSyntactic module, the donmartin theme.

- another intruder with the mooring in the heart of the Perl

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[Corion]: choroba: Re the one-shot thing, I also thought of bit vectors and/or indexes into one common array from the hashes, but that makes maintenance of all these indices a chorse
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[Corion]: So I guess I will simply implement the linear scan first and wait with more fancy stuff until it becomes a problem
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