Re^2: limiting scope of 'eval'??

Maybe because since at least 5.6.1, there isn't any real conflict.

#! perl -slw
use strict;

my( $a, $b ) = ( 'mya', 'myb' );

{
    our( $a, $b ) = ( 'oura', 'ourb' );
    my @sorted = sort { $a <=> $b } map{ rand 100 } 0 .. 99;
    print "$a : $b";
}
print "$a : $b";
__END__
P:\test>test
oura : ourb
mya : myb
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Comment on Re^2: limiting scope of 'eval'?? Download Code

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Re^3: limiting scope of 'eval'?? by bmann (Priest) on Aug 23, 2004 at 16:39 UTC
It's still best to avoid gratuitous use of $a and $b. When $a and $b are declared properly, no conflict. But if you forget to declare them, you can quietly get action at a distance. `#! perl -slw use strict; ( $a, $b ) = ( 'mya', 'myb' ); # imagine several lines of intervening code { our( $a, $b ) = ( 'oura', 'ourb' ); my @sorted = sort { $a <=> $b } map{ rand 100 } 0 .. 99; print "$a : $b"; } print "$a : $b"; __END__ C:\s>perl sortab.pl oura : ourb oura : ourb #no warnings, $a and $b are quietly changed` [download] The script dies if they are declared (with my instead of our) in the same scope as the sort routine: `#! perl -slw use strict; my( $a, $b ) = ( 'mya', 'myb' ); { my( $a, $b ) = ( 'oura', 'ourb' ); my @sorted = sort { $a <=> $b } map{ rand 100 } 0 .. 99; print "$a : $b"; } print "$a : $b"; __END__ C:\S\pl>perl sortab.pl Can't use "my $a" in sort comparison at sortab.pl line 10.` [download] Update: Deleted extra code tag	[reply] [d/l] [select]

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Re^3: limiting scope of 'eval'??
by bmann (Priest) on Aug 23, 2004 at 16:39 UTC

When $a and $b are declared properly, no conflict. But if you forget to declare them, you can quietly get action at a distance.

#! perl -slw
use strict;

( $a, $b ) = ( 'mya', 'myb' );
# imagine several lines of intervening code
{
    our( $a, $b ) = ( 'oura', 'ourb' );
    my @sorted = sort { $a <=> $b } map{ rand 100 } 0 .. 99;
    print "$a : $b";
}
print "$a : $b";
__END__
C:\s>perl sortab.pl
oura : ourb
oura : ourb #no warnings, $a and $b are quietly changed
[download]

The script dies if they are declared (with my instead of our) in the same scope as the sort routine:

#! perl -slw
use strict;

my( $a, $b ) = ( 'mya', 'myb' );

{
    my( $a, $b ) = ( 'oura', 'ourb' );
    my @sorted = sort { $a <=> $b } map{ rand 100 } 0 .. 99;
    print "$a : $b";
}
print "$a : $b";
__END__
C:\S\pl>perl sortab.pl
Can't use "my $a" in sort comparison at sortab.pl line 10.
[download]

Update:

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