Parsing arguments with surrounding garbage.

kschwab has asked for the wisdom of the Perl Monks concerning the following question:

Monks, I have a short script that looks for commands and arguments buried within an email message. Since email sometimes inserts garbage (salutations, signatures, etc) before and after the message text, I need to find valid commands within the text.

I know the list of valid commands, and in this case, valid args are numeric. So, for the input "garbage validcommand 1234 221 garbage 999 213", I need to parse out the args "1234 221", and throw the rest out. The number of args can vary.

I've found something that works, but it seems inelegant:

$string="garbage validcommand 1234  221 garbage 999 213";
while ($string =~ s/validcommand\s+(\d+)/validcommand /) {
    push(@args,$1);
}
[download]

Anyone have some better ideas ?

Comment on Parsing arguments with surrounding garbage. Download Code

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Re: Parsing arguments with surrounding garbage. by Albannach (Monsignor) on Apr 04, 2001 at 18:47 UTC
That doesn't look so inelegant to me, but here's a way that avoids the substitution, FWIW (though I'm sure someone can do better): `$string = 'garbage validcommand 1234 221 garbage 999 213'; $string =~ m/validcommand\s+((\d+\s+)+)/; @args = split ' ',$1;` [download] -- I'd like to be able to assign to an luser	[reply] [d/l]
Re: Parsing arguments with surrounding garbage. by busunsl (Vicar) on Apr 04, 2001 at 18:49 UTC
Don't use substitution here: `$string="garbage validcommand 1234 221 garbage 999 213 validcommand 1 +2 34 garbage"; while ($string =~ /validcommand\s+((\d+\s+)+)/g) { push @args, split /\s+/, $1; }` [download]	[reply] [d/l]
Re: Parsing arguments with surrounding garbage. by kilinrax (Deacon) on Apr 04, 2001 at 18:53 UTC
Since you want "1234 221", not "1234", which is what that regex will capture, and you really want to be using match, not substitute, I'd suggest this: `#!/usr/bin/perl -w use strict; my @args; my $string="garbage validcommand 1234 221 garbage 999 213"; while ($string =~ m!validcommand\s+(\d+(?:\s+\d+)*)!g) { push(@args, $1); } print @args;` [download]	[reply] [d/l]
Re: Re: Parsing arguments with surrounding garbage. by kschwab (Vicar) on Apr 04, 2001 at 19:14 UTC
Thanks, I was looking for a match instead of a substitute, so this and the other replies were helpful. A note on your comment: Since you want "1234 221", not "1234", which is what that regex will capture The code I posted does work (because it takes n trips through the while() loop), and pulls in both 1234 and 221 into @args. It's just uglier than I wanted. Thanks all !	[reply]