Re^11: Remove redundency from an array

OK, this case *would* be solved by
a local $_ before the do block (I confess ..)

use strict;
use warnings;
use Test::More tests => 2;

sub uinq { local $_; @_ = do { @$_{@_}=(); keys %$_ } } 

my @array = (1,1,3,3,2,3,5,7,5,2);

%$_ = ( f=>'oo', b=>'ar' );
is keys(%$_), 2;
print "@{[ uinq @array ]}\n";
is keys(%$_), 2;
[download]

That correction seems to be all what's needed here.
Thanks for clearing this up
But now it's late ...

Regards
mwa

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Re^12: Remove redundency from an array by ikegami (Patriarch) on Sep 24, 2007 at 21:47 UTC
That still modifies a global variable ...or ast least, it's suppose to. I found that it doesn't modify `%{''}` as it should! Your code is excercising a Perl bug! This gets better all the time. Again, easily solved by replacing `sub uinq { local $_; @_ = do { @$_{@_}=(); keys %$_ } }` with the simpler, safer `sub uinq { local %_; @_{@_}=(); keys %_ }` What's with the useless `do`? What's with the useless assignment to `@_`? Why use a reference when one isn't needed? Why use a symbolic reference when one isn't needed? Using the symbolic reference means there's now another variable to localize. That is, if the code didn't rely on a Perl bug.	[reply] [d/l] [select]
Re^13: Remove redundency from an array by mwah (Hermit) on Sep 25, 2007 at 06:36 UTC
ikegami:What's with the useless do? That has (1.) been carried over from the non-sub expression and (2.) it was too late (in the evening) to make substantial changes... ikegami:What's with the useless assignment to @_? This is clearly necessary when using the do{} block in its original context ikegami:Why use a reference when one isn't needed? I'd never ever use a reference if it isn't needed, but my perl588 doesn't complain about abusing $_ this way ;-) ikegami:Using the symbolic reference means there's now another variable to localize. OK, but which one? ikegami:That is, if the code didn't rely on a Perl bug? Or, "didn't rely on a Perl feature"? I don't really know. BTW, your version using %_ impicitely by @_ is very nice. I'd recommend to put this one `sub uinq { local %_; @_{@_}=(); keys %_ } my @array = (1,1,3,3,2,3,5,7,5,2); print join ',', uinq(@array), "\n"` [download] somwhere into perldoc (necessity shown by other posts). Thanks for your engagement! Regards mwa	[reply] [d/l]