Change the regex to accept the namespace prefix of the function name.

...roboticus

When your only tool is a hammer, all problems look like your thumb.

I am though not very good at the regex, I tired with the following, but it is not working. The regex is as below. Could any one help with this.

$data =~ /(.*?)\n((?:\w+\*?\s+)+)(\*?\:|\w+\s*)\s*\((.*?)\)(\s*\{)/gsx

First of all, unless you build a real parser, you're not going to get perfect results. But if your source code is formatted in a somewhat typical style, then you can frequently do a decent-enough job. The trick is figuring out a regular expression that captures what you want and ignores what you don't want.

So think of the difference between what the C functions look like versus what your C++ functions look like. The primary difference appears to be that your C++ functions can have colons in the name. So I'd think the first step would be to adjust the regex to allow colons in the words.

Your attempt has a bit of a problem: the chunk that gets the function name accepts either \*?: or \w+\s*. The | splits the parenthesis group into two different regexes, either of which may be satisfied. To get the colon in your identifiers, try (\*?[:\w]+\s*). Using the square brackets effectively adds the : into the word characters. After making that change, the regex will now accept things like:

Bibbity
Bobbity *foo::bar (baz) {
[download]

Which is roughly where you wanted to get to. Keep in mind, though that C++ type declarations can be tricky, so you may have to adjust other parts of your regex too. Things to consider:

• Should there be colons in other parts? probably!
• Is a single asterisk sufficient? no, you'll probably want to allow more than one
• What about spaces between the asterisk and the function name? perfectly legal

And these are only the ones I can think of off the top of my head. I'm sure there are other complexities that I haven't even thought of. (Afterthought: Such as templates!)

$ cat 1070117.pl 
#!/usr/bin/perl
use strict;
use warnings;

my $regex = qr/(.*?)\n((?:\w+\*?\s+)+)(\*?[:\w]+\s*)\s*\((.*?)\)(\s*\{
+)/;
my $text = "foo\nfizzy bar::baz(a b) {\nblarf\n";
if ($text =~ $regex) {
    print "Matched! $1, $2, $3\n";
}

$ perl 1070117.pl
Matched! foo, fizzy , bar::baz
[download]

If you're having trouble with regular expressions, then try installing YAPE::Regex::Explain and using it to explain your regular expressions. That can help you pinpoint where you're going astray. I don't use it very often (primarily because I keep forgetting that it exists!) but I find it handy when I remember about it.

...roboticus

When your only tool is a hammer, all problems look like your thumb.