From: Carl Youngblood <carl@...>
Date: 2002-11-04T03:56:29+09:00
Subject: Extending Hash

I'm trying to create a modified version of a Hash that, if it doesn't contain anything for a given key, will return whatever element it has that most closely matches the key.  Here's what I've done so far:

-----------------------------------
class FragHash < Hash
        def [](key)
                index = key.dup
                while !self.has_key?(index) and index.chop! != nil
                end
                return self.default if index.empty?
                return fetch(index)
        end
end
-----------------------------------

so if I do the following:

-----------------------------------
h = FragHash.new
h['t'] = 23
puts h['test']
-----------------------------------

the output is 23.  In other words, it didn't find the index "test" but it kept shortening the index until it found something that matches.  The only problem I have now is that I want to make it so that when I call each() it also enumerates through the default value.  However, I don't know how to extend the each function (I'm still a little hazy on how to overload functions that use blocks).  It would be nice if I could look at the source for the Hash class itself.  Does anyone know where I can find it?  Does anyone have any suggestions for how I might modify the each function?

Thanks,
Carl Youngblood