Re^2: Using qw to check for balanced parentheses

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Re^3: Using qw to check for balanced parentheses by jwkrahn (Abbot) on Feb 02, 2011 at 01:08 UTC
Yes, that works a lot better. `:-)` Of course, the subroutine could be reduced to just: `sub is_balanced { eval "qw($_[0])" }` [download] And it will also work with `qq` as well as with `qw`. $ perl -le' sub is_balanced { eval qq($_[0]) } my $balanced = "(1 + 2 * (3 + (5/4) + 8) + 6)"; my $unbalanced1 = "(((1 + 2 * (3 + (5/4) + 8) + 6))"; my $unbalanced2 = "(((1 + 2 * (3 + (5/4) + 8) + 6))))"; print "Is $balanced balanced? ", is_balanced( $balanced ) ? "yes" : "n +o"; print "Is $unbalanced1 balanced? ", is_balanced( $unbalanced1 ) ? "yes +" : "no"; print "Is $unbalanced2 balanced? ", is_balanced( $unbalanced2 ) ? "yes +" : "no"; ' Is (1 + 2 * (3 + (5/4) + 8) + 6) balanced? yes Is (((1 + 2 * (3 + (5/4) + 8) + 6)) balanced? no Is (((1 + 2 * (3 + (5/4) + 8) + 6)))) balanced? no [download]	[reply] [d/l] [select]
Re^4: Using qw to check for balanced parentheses by ikegami (Patriarch) on Feb 02, 2011 at 02:00 UTC
That won't handle `""` hand `"0"`, but that's easy to fix: `sub is_balanced { eval "qw($_[0]); 1" }` [download]	[reply] [d/l] [select]
Re^4: Using qw to check for balanced parentheses by Anonymous Monk on Feb 02, 2011 at 01:13 UTC
`sub is_balanced2 { not $_[0] =~ tr/)(// % 2; }`	[reply] [d/l]
Re^5: Using qw to check for balanced parentheses by Your Mother (Archbishop) on Feb 02, 2011 at 01:29 UTC
Update: nothing but down votes for this...? This is output from using the above snippet, not suggested results. `)( is balanced ))))(()((( is balanced` [download]	[reply] [d/l]
Re^6: Using qw to check for balanced parentheses by Anonymous Monk on Feb 02, 2011 at 01:46 UTC
Re^3: Using qw to check for balanced parentheses by unix_hacker_beard (Novice) on Feb 02, 2011 at 01:27 UTC
D'oh! Thanks, I'm too used to dereferencing arrays.	[reply]