[ ruby-Patches-9055 ] Dynamic Array#join with block

Patches item #9055, was opened at 2007-03-05 19:57
You can respond by visiting: 
http://rubyforge.org/tracker/?func=detail&atid=1700&aid=9055&group_id=426

Category: None
Group: None
Status: Open
Resolution: None
Priority: 3
Submitted By: Farrel Lifson (farrel)
Assigned to: Nobody (None)
Summary: Dynamic Array#join with block

Initial Comment:
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:
 [[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.

The original functionality of join (without a block) is unchanged.

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You can respond by visiting: 
http://rubyforge.org/tracker/?func=detail&atid=1700&aid=9055&group_id=426