Re: Variable assignment error checking

in reply to Variable assignment error checking

I think changing the sub to return $var in event of it being unable to complete its intended purpose would be the best option.

I don't like it but if changing the sub can't be done then this is the most consice method I could think of.

use strict;
use warnings;

my $var = 'foo';

my $tmp;
$var = ( $tmp = return_false() ) ? $tmp : $var;

print "$var\n";

$var = ( $tmp = return_true() ) ? $tmp : $var;

print "$var\n";


sub return_true
{
    return 'bar';
}

sub return_false
{
    return;
}
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Comment on Re: Variable assignment error checking Download Code

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Re^2: Variable assignment error checking by NetWallah (Canon) on Dec 15, 2013 at 01:51 UTC
It is arguably more readable to save off the old value, and re-instate it if func returns undef/zero: `my $oldval; $val = func( $oldval=$val) \|\| $oldval;` [download] Newer perl's allow the alternative of using the // (defined or) operator. To maintain the challange of "not creating a new variable", one could try: `$val = func( $_=$val) \|\| $_;` [download] Add a BLOCK, if $_ is being abused: `$val = do{ func( local $_=$val) \|\| $_ };` [download] When in doubt, mumble; when in trouble, delegate; when in charge, ponder. -- James H. Boren	[reply] [d/l] [select]

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Re^2: Variable assignment error checking
by NetWallah (Canon) on Dec 15, 2013 at 01:51 UTC

my $oldval;

$val = func( $oldval=$val) || $oldval;
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To maintain the challange of "not creating a new variable", one could try:

  $val = func( $_=$val) || $_;
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    $val = do{ func( local $_=$val) || $_ };
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When in doubt, mumble; when in trouble, delegate; when in charge, ponder. -- James H. Boren

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