From: "ako..." <akonsu@...>
Date: 2005-12-16T06:12:39+09:00
Subject: Re: regular expressions question

yes, thank you. this is a better description of the problem. i am not a
native english speaker, so may be this is one of the reasons why my
question is not clear.

i saw a solution to this problem that uses split at the end. it of
course won't work if you change your example and allow quoted strings
in source-words and destination-words. a quoted string can contain
anything, spaces too and your keywords too, so the subsequent split
won't work.

well, i did not realise that the term "group's captures" is that rare.
i thought it was a standard term. but may be i am brainwashed by
microsoft. so i have this code in .net which might help to clarify what
i am talking about:

            string text = "One car red car blue car";
            string pat = @"^(?:(\w+)\s+)*(\w+)$";
            Regex r = new Regex(pat, RegexOptions.IgnoreCase);

            // Match the regular expression pattern against a text
string.
            Match m = r.Match(text);
            if (m.Success)
            {
                Console.WriteLine("match: [{0}]", m);
                foreach (Group g in m.Groups)
                {
                    Console.WriteLine("group: [{0}]", g);
                    foreach (Capture c in g.Captures)
                    {
                        Console.WriteLine("\tcapture: [{0}]", c);
                    }
                }
            }

the output is:

match: [One car red car blue car]
group: [One car red car blue car]
        capture: [One car red car blue car]
group: [blue]
        capture: [One]
        capture: [car]
        capture: [red]
        capture: [car]
        capture: [blue]
group: [car]
        capture: [car]

as you see, the first group is $0, the second group is $1, and the
third is $2. but $1 and $2 contain captures too. it is like if $1 and
$2 were arrays in Ruby.

in my opinion this is a big limitation of ruby's regular expressions.
it just must be as powerful as .net ; -)

konstantin