From: Warren Brown <wkb@...>
Date: 2003-06-10T04:52:13+09:00
Subject: Re: [RCR] join block

Simon,

>> As for the block working on individual
>> elements, that's map's job.
>
> cjoin = collect-join
> pjoin = pair-join
>
> I still think 'cjoin' is much more often used
> in practice than 'pjoin'.

    I use 'puts foo.join("\n")' quite often too, but I wouldn't suggest
adding a puts_join() method to the language - even though it wouldn't break
any existing code :o)

    It's not a question of which one is used more often, it is a question of
orthagonality.  Array#join's job is to insert a string between pairs of
adjacent elements.  Array#map()'s job is to process elements one at a time
and collect the output into a new array.  If Array#join were to take a
block, the block would need to be used to generate the string to insert
between adjacent elements.  That is why Joel suggested the '[1,2,3].join
{|x,y| x < y ? " < " : " >= " }' methodology.

    I don't really think that it is worth adding this to the language,
especially since there is a problem with the new Array#join being able to
take both a string argument and a (conflicting) block.  I think that this is
just another case of a request for a change to the language, someone
pointing out that the change is not a good idea but offering an alternative
change that does make sense.

    I hope this helps clarify things...

    - Warren Brown