From: Brian Candler <b.candler@...>
Date: 2009-06-22T21:52:07+09:00
Subject: Re: regular expression gurus--help!

Robert Dober wrote:
> Who feels with me that allowing you to do
> 
> coll.map( &:join )
> 
> but forbidding
> 
> coll.map( &:join, ", " )
> 
> is a shame.

I think it's pretty ugly - especially the fact that you need the 
argument ", " to be passed to join, not to map, and yet it appears in 
map's argument list.

> Now it is clear that the above is not correct Ruby syntax. From my
> experience very few people are fond of
> the magic dot, which would solve the problem elegantly.
> 
> coll.map.join( ", " )
> 
> although in a very condensed way.

That I dislike very much. What you want is to run a 'join' operation on 
*each member* of the collection, but that looks like running a .map.join 
on the *whole* collection. From that point of view,

  coll.map { |c| c.join(",") }

expresses very clearly what you're doing.
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