in reply to Re: Using qw to check for balanced parentheses (oops)
in thread Using qw to check for balanced parentheses

sub balanced {
    local $_ = shift;
    s/[^()]//g;
    eval "qw($_)";
    ! $@
}

[download]

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Re^3: Using qw to check for balanced parentheses (oops)
by ikegami (Patriarch) on Sep 16, 2011 at 19:51 UTC

    Simplified return value and shortened code by avoiding needless use of $_: 

    sub balanced {
    (my $s = shift) =~ s/[^()]//g;
    eval "qw($s); 1"
}

    [download]

    Or in 5.14+: 

    sub balanced {
    my $s = shift =~ s/[^()]//rg;
    eval "qw($s); 1"
}

    [download]
[reply]
[d/l]
[select]

      I may be mistaken, but this does not detect a case like

      "}a{"

      , or does it?

      how about

      sub balanced {
    (my $s = shift) =~ s/[^()]//g;
    while ( $s =~s /\(\)// ){};
    return $s ? 0 : 1;
}

      [download]
      It does not use qr and is slower, I would think, but reports '}{' as incorrect
[reply]
[d/l]
Re^3: Using qw to check for balanced parentheses (oop)
by tye (Sage) on Sep 16, 2011 at 19:42 UTC

    Very nice!

    - tye        

[reply]

In Section Cool Uses for Perl