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add ?subseq, ?tail*, ?head*

db4
Doug Coleman 2008-02-18 17:07:01 -06:00
parent d6ede4dda5
commit d98fd6e758
2 changed files with 12 additions and 5 deletions
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4
extra/sequences/lib/lib-tests.factor
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@ -20,8 +20,6 @@ IN: temporary
[ 10 ] [ { 1 2 3 4 } [ + ] reduce* ] unit-test
[ 24 ] [ { 1 2 3 4 } [ * ] reduce* ] unit-test
[ 1 2 3 4 ] [ { 1 2 3 4 } 4 nfirst ] unit-test
[ -4 ] [ 1 -4 [ abs ] higher ] unit-test
[ 1 ] [ 1 -4 [ abs ] lower ] unit-test
@ -80,4 +78,4 @@ IN: temporary
{ 13 } [ 1 2 { 3 4 } [ + + ] 2 each-withn + ] unit-test
[ { 910 911 912 } ] [ 10 900 3 [ + + ] map-with2 ] unit-test
[ 1 2 3 4 ] [ { 1 2 3 4 } 4 nfirst ] unit-test
[ 1 2 3 4 ] [ { 1 2 3 4 } 4 firstn ] unit-test

13
extra/sequences/lib/lib.factor
View File

@ -18,8 +18,9 @@ IN: sequences.lib
: map-with2 ( obj obj list quot -- newseq ) 2 map-withn ; inline
MACRO: nfirst ( n -- )
[ [ swap nth ] curry [ keep ] curry ] map concat [ drop ] compose ;
MACRO: firstn ( n -- )
[ [ swap nth ] curry
[ keep ] curry ] map concat [ drop ] compose ;
: prepare-index ( seq quot -- seq n quot )
>r dup length r> ; inline
@ -182,6 +183,14 @@ PRIVATE>
: ?first3 ( seq -- 1st/f 2nd/f 3rd/f ) dup ?first2 rot ?third ; inline
: ?first4 ( seq -- 1st/f 2nd/f 3rd/f 4th/f ) dup ?first3 roll ?fourth ; inline
USE: continuations
: ?subseq ( from to seq -- subseq )
>r >r 0 max r> r>
[ length tuck min >r min r> ] keep subseq ;
: ?head* ( seq n -- seq/f ) (head) ?subseq ;
: ?tail* ( seq n -- seq/f ) (tail) ?subseq ;
: accumulator ( quot -- quot vec )
V{ } clone [ [ push ] curry compose ] keep ;