Re: [PATCH] Join with block

"Farrel Lifson" <[e-mail]> writes:
> This patch adds the ability to give the Array#join method a block like so
> [1,3,2,4].join(' which is X than '){|sep,a,b| a > b ?
> sep.sub(/X/,"#{a-b} more") : sep.sub(/X/,"#{b-a} less")}
> which produces
> 1 which is 2 less than 3 which is 1 more than 2 which is 2 less than 4
>
> The patch is based off the original rb_ary_join and so it handles
> nested arrays in the same recursive manner as rb_ary_join:
>  [[1,2],[3,4]].join {|sep,a,b| b.class.eql?(Array) ? "->" : ":"}
> which produces
>  1:2->3:4
>
> The parameters passed into the block are the separator string (sep)
> which is the parameter passed to the join method, and the two elements
> (a,b) between which sep will be inserted.
>
> The following methods are added/modified:
>
>  * rb_ary_join_m : Calls rb_ary_join or rb_ary_join_block depending
> on whether a block is given.
>  * rb_ary_join_block: Performs the join using the given block.
>  * recursive_join_block: Same functionality as recursive_join but
> calls rb_ary_join_block.
>
> Tests are added to sample/test.rb and the definition of
> rb_ary_join_block is added to intern.h.
>
> Unfortunately due to some weird transparent proxy errors in South
> Africa, I can't log into Rubyforge to add this to the Ruby project
> patch tracker. If someone could submit it for me I would appreciate it
> (that is if it doesn't get shot out the sky here first)
>
> Thanks,
> Farrel

Why bother passing sep to the block?

Can your implementation handle [1,2,3].join {...} => "1, 2 and 3"?

Steve