[REBOL] Re: COLLECTing results
From: AJMartin:orcon at: 24-Jul-2003 18:32
> >> foreach [a b] [1 2 3 4] collect [a + b]
> == [3 7]
Unfortunately, it fails in this case:
>> foreach [a b] [1 2 3 4] collect [print a print b a + b]
1
2
3
4
== [unset unset]
But this version:
>> collect: func [
[ {Collects block evaluations, use with For, Repeat, etc.}
[ block [block!]
[ /init result "Initialise the result series."
[ /only "Inserts into result using Only refinement."
[ ] [
[ if empty? block [return block]
[ compose/deep [
[ result: any [result make block! 100]
[ (pick [insert/only insert] found? only) tail result do
[(block)]
[ result
[ ]
[ ]
...works bettter:
>> foreach [a b] [1 2 3 4] collect [print a print b a + b]
1
2
3
4
== [3 7]
:)
Note:
compose/deep
and:
do [(block)]
Andrew J Martin
ICQ: 26227169 http://www.rebol.it/Valley/ http://Valley.150m.com/
