From: Ryan Davis <ryand-ruby@...>
Date: 2009-04-16T18:34:16+09:00
Subject: Re: Tokenizing a large file


On Apr 16, 2009, at 02:27 , Robert Klemme wrote:

> Converted to the block form:
>
> def my_tokenize file
>  tokens = Hash.new {|h,k| h[k.freeze] = k}

FYI:

% irb
 >> h = {}
=> {}
 >> h["key"] = 42
=> 42
 >> h.keys.map { |k| k.frozen? }
=> [true]

hashes dupe and freeze string keys to prevent them from being mutated  
while hash keys.