Re: A perverse use of grep

You were right in the code smell, but wrong in your fix. It's poor style because someone's trying to be cool and do everything on one line. Instead, the code should really be something like:

my @lines;
{ local $_;
    while ( <$in> )
    {
        # Remove leading and trailing whitespace
        s/^\s+//; s/\s+$//;

        # Remove comments from the first # to the end of the line
        s/#.*//;

        push @lines, $_ if length $_;
    }
}
[download]

Are you paying for your whitespace or something??

Update: Fixed bug as per brian_d_foy's comment.

Update: Changed per demerphq's comment.

Update: Added bare-block to localize $_ per itub's comment. I don't think this is completely necessary, but it's good to be anal.

In general, if you think something isn't in Perl, try it out, because it usually is. :-)
"What is the sound of Perl? Is it not the sound of a wall that people have stopped banging their heads against?"

Comment on Re: A perverse use of grep Download Code

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Re^2: A perverse use of grep by brian_d_foy (Abbot) on Jun 15, 2005 at 03:05 UTC
Your code reproduces the bug of ignoring the line that is the bare '0'. You don't want to test the value of the line, but its length. -- brian d foy <brian@stonehenge.com>	[reply]
Re^2: A perverse use of grep by eyepopslikeamosquito (Archbishop) on Jun 15, 2005 at 03:16 UTC
Well, it is not "my" code; I inherited it and have to maintain it. Despite my dubious past as a golfer, I never play golf on production code. ;-) I like your approach, BTW.	[reply]
Re^2: A perverse use of grep by demerphq (Chancellor) on Jun 15, 2005 at 09:44 UTC
IMO the expanded style is bad form: `while ( defined( $_ = <$in> ) )` [download] should be written `while (<$in>) {` [download] --- $world=~s/war/peace/g	[reply] [d/l] [select]
Re^3: A perverse use of grep by itub (Priest) on Jun 15, 2005 at 17:20 UTC
I would also recommend localizing `$_`, because `while` doesn't do it automatically: `sub whatever { local $_; while(<$in>) { # do stuff } }` [download] Even if the loop is not in a sub, localizing $_ can prevent nasty bugs if you decided to wrap the loop in a sub later.	[reply] [d/l] [select]
Re^3: A perverse use of grep by dragonchild (Archbishop) on Jun 15, 2005 at 12:01 UTC
You're right ... I originally had `while (defined( my $line = <$in> ))` and never got rid of the expanded form when I went back to $_. Updated. In general, if you think something isn't in Perl, try it out, because it usually is. :-) "What is the sound of Perl? Is it not the sound of a wall that people have stopped banging their heads against?"	[reply] [d/l]