Monks --

I'm sure that I am just overlooking something here, but this is driving me bananas. I am trying to process delimited files, whose lines look like this:

acb,def,123,456

etc. The delimiter might be any printable character, including regexp meta characters like ^, |, etc. I need to read the lines from the input, split them into fields, "do stuff", join them back together with (probably) a different delimiter, and then write them to the output. In the process, I need to do a match on the input lines to make sure that they don't already contain the output delimiter.

The rub is that I am trying to allow the user to specify the delimiters on the command line. I'm getting them with getopts just fine, but I run into problems when I'm doing the match (m//) on the new delimiter and split with the old delimiter, when those happen to be regexp meta characters. 

$foo = '^';
m/$foo/

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isn't working for me no matter how I escape it. I think that the problem is that Perl processes the string twice, once to interpolate the variables and a second to interpret the regexp. What would be ideal for me is a way to tell Perl that this isn't a regexp, just a literal string, and it should ignore the meta character.

What am I missing here?

Thanks!

-- David

Update:

I've got it working. One thing I forgot to mention is that the input delimiter might be a tab. /Q..../E and quotemeta on which they depend escape everything except alphanumerics, which wasn't adequate for me, because they quote the tab.

What I did instead is this: 

my $str = "acb^def^123^456";
my $foo = '^'; 
$foo =~ s/([\\\|\(\)\[\{\^\$\*\+\?\.])/\\$1/;
my @fields = split /$foo/, $str;
my $out = join '|', @fields;
print "$out\n";

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which explicitly quotes the metacharacters and only the metacharacters. This also works for: 

my $str = "acb\tdef\t123\t456";
my $foo = "\t";

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and should work for any other delmiter, although I have not tested everything. Using an existing delimiter parser is less appealing to me because my (ridiculous) incoming data sources think that 

"first,field","second,""field"with','junk","third'field

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is three fields. My current program doesn't handle quoted delmiters, but soon I wil have to.

Thanks much for your help!

-- David

In reply to escaping variables in regexp by Getch

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