From: Robert Klemme <bob.news@...>
Date: 2006-02-23T19:53:42+09:00
Subject: Re: setting nil to zero

Botp wrote:
> Robert Klemme [mailto:bob.news@gmx.net] :
>
> #f[w] = (f[w] || 0) + 1
>
> clear rubyish solution, Robert.
> thanks again for generous help.
>
> i am still hoping for the plain f[w] += 1 though :)

As mentioned already you can do that, if it's a Hash:

>> f=Hash.new 0
=> {}
>> f[:foo]+=1
=> 1
>> f
=> {:foo=>1}

> for the record, i played w the ff
>
> ruby>cat test.rb
>
> class NilClass
>    def method_missing(methId, *args)
>       str = methId.id2name
>       if str == "+" and args[1].nil?
>          #str is "+"
>          #args[1]  is nil
>          #args[0]  is rhs value
>          return args[0]
>       end
>    end
> end

Why so complicated?  Why not just

class NilClass
  def +(n) n end
end

>> h={}
=> {}
>> h[:foo]+=1
=> 1
>> h
=> {:foo=>1}

Note, I recommend to use the veriant with 0 as default value for Hash
lookups because that avoids tampering with standard classes.

Cheers

    robert