From: Dave Thomas <Dave@...>
Date: 2001-08-23T06:19:02+09:00
Subject: [ruby-talk:20123] Re: Maximum Surprise

Bob Gustafson <bobgus@mcs.com> writes:

> However, I was surprised to find out that the construction
> 
> lots = Hash.new
> lots['ALA'] = 2
> lots['IBM'] = 4
> 
> lots.keys do |k|
>   puts k
> end
> 
> does not print out anything, nor does it flag a syntax violation.  This
> was a "Maximum Surprise".

You can associate a block with any method in Ruby, and there's no real
way of knowing whether or not you;re invoking a method that does take
a block. In this case, you were passing a block to 'keys' and keys
just quietly ignored the fact. It really isn't a syntax
issue. However, it might be possible to generate a warning at runtime
if you pass a block to a method that doesn't use it (either with an &
parameter or by calling yield). Matz?



Regards


Dave