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sequences.extras: Add count-head and count-tail

elevate-erg
Doug Coleman 2018-07-04 18:32:19 -05:00
parent 147d13ed19
commit 000f3eab07
1 changed files with 7 additions and 0 deletions
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extra/sequences/extras/extras.factor
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@ -628,6 +628,13 @@ PRIVATE>
[ '[ @ not ] find drop ] keepd swap [ '[ @ not ] find drop ] keepd swap
[ dup length ] unless* tail-slice ; inline [ dup length ] unless* tail-slice ; inline
: count-head ( seq quot -- n )
[ not ] compose find drop ; inline
: count-tail ( seq quot -- n )
[ not ] compose [ find-last drop ] 2keep drop
length swap [ - 1 - ] when* ; inline
:: interleaved-as ( seq glue exemplar -- newseq ) :: interleaved-as ( seq glue exemplar -- newseq )
seq length dup 1 - + 0 max exemplar new-sequence :> newseq seq length dup 1 - + 0 max exemplar new-sequence :> newseq
seq [ 2 * newseq set-nth-unsafe ] each-index seq [ 2 * newseq set-nth-unsafe ] each-index