how to express $temp =~ s/.*?from://; in perl 4

[Anonymous Monk]

Hi all, I'm using perl 5.6.0 to program $temp =~ s/.*?from://; this way, however, if i would like to run my program under perl 4 version, i find the ? operation is not allowed. How can i modify my code to run correctly!? THX alot

[splinky]

Since you're looking for a constant string, you can use substr and index in place of the regex, like so:

$temp = substr ( $temp, index ( $temp, 'from:' ) + 5 )
  if $temp =~ /from:/;

Note that, since I don't have Perl 4 installed anywhere, the code above is untested under Perl 4.

*Woof*

[davorg]

Don't do that. Perl 4 has known security issues. You shouldn't be using it for anything. Please upgrade to Perl 5.

--
<http://www.dave.org.uk>

European Perl Conference - Sept 22/24 2000, ICA, London
<http://www.yapc.org/Europe/>

[young perlhopper]

I assume from your regex that you are expecting more than one 'from:' to appear in the string and you only want to deal with everything up to the first one. It is easy to simply make the .* nongreedy, but would it be possible for you to make a more specific regular expression that would take into account what comes before or after the from:? i.e. if you are expecting a number to come after this four, but you won't see a number after any other four, then do:


$temp =~ s/.*from:( \d+)/$1/;

Unless you are optimizing for speed, I consider it a good habit to make regex's as specific as possible so that you avoid matching unwanted strings without knowing it.

Hope this helps,
Mark

[Anonymous Monk]

Use a negated character class:

$temp = "notfrom:nowhere";
# Match zero or more non-f characters followed by "from:"
$temp =~ s/[^f]*from://;
print "$temp\n";

Prints "nowhere".

[merlyn]

That's not the same as finding the nearest match:

$text = "fanny farmer from: big sky";

There's no trivial way to say "a string of text that doesn't contain FROM" in Perl 4 regex. There are many wrong ways that people attempt. :)

-- Randal L. Schwartz, Perl hacker

[Anonymous Monk]

What site are you gonna be running this on?
I want to take advantage of your Perl 4 stupidity and destroy everything on the site.