[REBOL] Re: 'get'ing a 'word from a block
From: tim:johnsons-web at: 1-Jan-2003 8:00
Thanks to all for helping me to find my
solution!
regards
-tim-
* Volker Nitsch <[nitsch-lists--netcologne--de]> [021231 23:10]:
> d: [a b c]
> blk: [1 2 3 4 5 6 7 8 9]
> test: func [row [block!]] [?? row ?? a probe reduce row]
> forskip blk length? d[ set d blk test d]
> blk: head blk ;if you need blk later
> > row: [a b c]
> a: 1
> [1 2 3]
> row: [a b c]
> a: 4
> [4 5 6]
> row: [a b c]
> a: 7
> [7 8 9]
>
> Tim Johnson wrote:
>
> >Thank you Anton! I forgot about 'bind.
> >
> >I'm still in the dark a bit though, because
> >I really want to get the values for 'a 'b 'c
> >in 'test
> >If I rewrite test as :
> > test: func [row [block!]][?? row ?? a]
> >
> >>>foreach :d blk code: [
> >>>
> >[ ?? a ?? b ?? c
> >[ test reduce bind d 'a
> >[ ]
> >a: 1
> >b: 2
> >c: 3
> >row: [1 2 3]
> >** Script Error: a has no value
> >** Where: rejoin
> >** Near: mold name: get name
> >
> >If possible, I would want to get
> >'row as [a b c]
> >and 'get 1 from a.
> >
> >Is this possible?
> >
> >And Happy New Year!
> >-tim-
> >
> >* Anton <[anton--lexicon--net]> [021231 21:10]:
> >
> >>Well,
> >>
> >>Your block d contains three words, a b c, whose
> >>context is... in that block... (I think).
> >>You need to bind the words in the d block into
> >>the foreach's context (which we can get to using
> >>'a as an example word in that context.)
> >>
> >>Having bound the words in d to the foreach context,
> >>they are still simply [a b c], so you need to
> >>reduce the block get a block of values out.
> >>
> >>So a bit of binding and reducing and you are fixed:
> >>
> >> d: [a b c]
> >> blk: [1 2 3 4 5 6 7 8 9]
> >> test: func [row [block!]][?? row]
> >> foreach :d blk code: [
> >> ?? a ?? b ?? c
> >> test reduce bind d 'a
> >> ]
> >>
> >>Anton.
> >>
> >>>Hello Rebols:
> >>> I have an example below where foreach sets a block
> >>>of values, but I don't know how to retain those
> >>>values within the block when I pass the block to
> >>>another function:
> >>>
> >>>>>d: [a b c]
> >>>>>
> >>>== [a b c]
> >>>
> >>>>>blk: [1 2 3 4 5 6 7 8 9]
> >>>>>
> >>>== [1 2 3 4 5 6 7 8 9]
> >>>
> >>>>>test: func[row[block!]][?? row ?? a]
> >>>>>foreach :d blk[?? a ?? b ?? c test d]
> >>>>>
> >>>a: 1
> >>>b: 2
> >>>c: 3
> >>>; foreach sets the values in the block correctly
> >>>row: [a b c]
> >>>; the words are passed in the block to 'test
> >>>** Script Error: a has no value
> >>>** Where: rejoin
> >>>** Near: mold name: get name
> >>>; alas, can't get the value
> >>>
> >>>What am I doing wrong here?
> >>>TIA
> >>>--
> >>>Tim Johnson <[tim--johnsons-web--com]>
> >>>
> >
>
> -volker
>
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--
Tim Johnson <[tim--johnsons-web--com]>
http://www.alaska-internet-solutions.com
http://www.johnsons-web.com
