1 USING: accessors arrays assocs combinators generalizations
2 grouping growable kernel math math.order ranges sequences
3 sequences.private shuffle sorting splitting vectors ;
6 : find-all ( ... seq quot: ( ... elt -- ... ? ) -- ... elts )
7 [ <enumerated> ] dip '[ nip @ ] assoc-filter ; inline
9 : reduce-from ( ... seq identity quot: ( ... prev elt -- ... next ) i -- ... result )
10 [ swap ] 2dip each-from ; inline
12 :: subseq* ( from to seq -- subseq )
14 from [ dup 0 < [ len + ] when ] [ 0 ] if*
15 to [ dup 0 < [ len + ] when ] [ len ] if*
16 [ 0 len clamp ] bi@ dupd max seq subseq ;
18 : safe-subseq ( from to seq -- subseq )
19 [ length '[ 0 _ clamp ] bi@ ] keep subseq ;
21 : all-subseqs ( seq -- seqs )
22 dup length [1..b] [ clump ] with map concat ;
24 :: each-subseq ( ... seq quot: ( ... subseq -- ... ) -- ... )
27 from len (a..b] [| to |
28 from to seq subseq quot call
32 : map-like ( seq exemplar -- seq' )
33 '[ _ like ] map ; inline
35 : filter-all-subseqs-range ( ... seq range quot: ( ... subseq -- ... ? ) -- seq )
37 '[ <clumps> _ filter ] with map concat
38 ] keepdd map-like ; inline
40 : filter-all-subseqs ( ... seq quot: ( ... subseq -- ... ? ) -- seq )
41 [ dup length [1..b] ] dip filter-all-subseqs-range ; inline
43 :: longest-subseq ( seq1 seq2 -- subseq )
48 len1 1 + [ len2 1 + 0 <array> ] replicate :> table
52 y 1 - seq2 nth-unsafe = [
53 y 1 - x 1 - table nth-unsafe nth-unsafe 1 + :> len
54 len y x table nth-unsafe set-nth-unsafe
55 len n > [ len n! x end! ] when
56 ] [ 0 y x table nth-unsafe set-nth-unsafe ] if
58 ] each end n - end seq1 subseq ;
60 : pad-longest ( seq1 seq2 elt -- seq1 seq2 )
61 [ 2dup max-length ] dip [ pad-tail ] 2curry bi@ ;
63 : pad-center ( seq n elt -- padded )
64 swap pick length [-] [ drop ] [
65 [ 2/ ] [ over - ] bi rot '[ _ <repetition> ] bi@
69 : change-nths ( ... indices seq quot: ( ... elt -- ... elt' ) -- ... )
70 [ change-nth ] 2curry each ; inline
72 : push-if-index ( ..a elt i quot: ( ..a elt i -- ..b ? ) accum -- ..b )
73 [ keepd ] dip rot [ push ] [ 2drop ] if ; inline
75 : push-if* ( ..a elt quot: ( ..a elt -- ..b obj/f ) accum -- ..b )
76 [ call ] dip [ push ] [ drop ] if* ; inline
80 : (index-selector-as) ( quot length exampler -- selector accum )
81 new-resizable [ [ push-if-index ] 2curry ] keep ; inline
83 : (selector-as*) ( quot length exemplar -- selector accum )
84 new-resizable [ [ push-if* ] 2curry ] keep ; inline
88 : index-selector-as ( quot exemplar -- selector accum )
89 [ length ] keep (index-selector-as) ; inline
91 : index-selector ( quot -- selector accum )
92 V{ } index-selector-as ; inline
94 : selector-as* ( quot exemplar -- selector accum )
95 [ length ] keep (selector-as*) ; inline
97 : selector* ( quot -- selector accum ) V{ } selector-as* ; inline
99 : filter-index-as ( ... seq quot: ( ... elt i -- ... ? ) exemplar -- ... seq' )
100 pick length over [ (index-selector-as) [ each-index ] dip ] 2curry dip like ; inline
102 : filter-index ( ... seq quot: ( ... elt i -- ... ? ) -- ... seq' )
103 over filter-index-as ; inline
105 : even-indices ( seq -- seq' )
106 [ length 1 + 2/ ] keep [
107 [ [ 2 * ] dip nth-unsafe ] curry
108 ] keep map-integers ;
110 : odd-indices ( seq -- seq' )
112 [ [ 2 * 1 + ] dip nth-unsafe ] curry
113 ] keep map-integers ;
115 : compact ( ... seq quot: ( ... elt -- ... ? ) elt -- ... seq' )
116 [ split-when harvest ] dip join ; inline
118 : collapse ( ... seq quot: ( ... elt -- ... ? ) elt -- ... seq' )
120 [ [ harvest ] dip join ]
121 [ [ first empty? ] dip [ prepend ] curry when ]
122 [ [ last empty? ] dip [ append ] curry when ]
125 :: slice-when ( seq quot: ( elt -- ? ) -- seq' )
128 dup seq quot find-from drop
129 [ 2dup = [ 1 + ] when ] [ len ] if*
130 [ seq <slice> ] keep len or swap
131 ] produce nip ; inline
133 : ?<slice> ( from/f to/f sequence -- slice )
134 [ [ 0 ] unless* ] 2dip
135 over [ nip [ length ] [ ] bi ] unless
138 : sequence>slice ( sequence -- slice )
139 [ drop 0 ] [ length ] [ ] tri <slice> ; inline
141 : slice-order-by-from ( slice1 slice2 -- slice-lt slice-gt )
142 2dup [ from>> ] bi@ > [ swap ] when ; inline
144 : ordered-slices-range ( slice-lt slice-gt -- to from )
145 [ to>> ] [ from>> ] bi* ;
147 : unordered-slices-range ( slice1 slice2 -- to from )
148 slice-order-by-from ordered-slices-range ;
150 : ordered-slices-overlap? ( slice-lt slice-gt -- ? )
151 ordered-slices-range > ; inline
153 : unordered-slices-overlap? ( slice1 slice2 -- ? )
154 unordered-slices-range > ; inline
156 : slices-overlap? ( slice1 slice2 -- ? )
157 unordered-slices-overlap? ;
159 : ordered-slices-touch? ( slice-lt slice-gt -- ? )
160 ordered-slices-range >= ; inline
162 : unordered-slices-touch? ( slice1 slice2 -- ? )
163 unordered-slices-range >= ; inline
165 : slices-touch? ( slice1 slice2 -- ? )
166 unordered-slices-touch? ;
168 ERROR: slices-don't-touch slice1 slice2 ;
170 : merge-slices ( slice1 slice2 -- slice/* )
172 2dup ordered-slices-touch? [
173 [ from>> ] [ [ to>> ] [ seq>> ] bi ] bi* <slice>
178 : rotate ( seq n -- seq' )
179 over length mod dup 0 >= [ cut ] [ abs cut* ] if prepend ;
181 ERROR: underlying-mismatch slice1 slice2 ;
183 : ensure-same-underlying ( slice1 slice2 -- slice1 slice2 )
184 2dup [ seq>> ] bi@ eq? [ underlying-mismatch ] unless ;
186 : span-slices ( slice1 slice2 -- slice )
187 ensure-same-underlying
188 [ [ from>> ] bi@ min ]
190 [ drop seq>> ] 2tri <slice> ;
192 : ?span-slices ( slice1/f slice2/f -- slice )
193 2dup and [ span-slices ] [ or ] if ;
195 :: rotate! ( seq n -- )
197 n len mod dup 0 < [ len + ] when seq bounds-check drop 0 over
199 [ seq exchange-unsafe ] [ [ 1 + ] bi@ ] 2bi
200 dup len = [ drop over ] when
201 2over = [ -rot nip over ] when
204 : all-rotations ( seq -- seq' )
205 dup length <iota> [ rotate ] with map ;
209 : (appender-for) ( quot length exemplar -- appender accum )
210 new-resizable [ [ push-all ] curry compose ] keep ; inline
214 : appender-for ( quot exemplar -- appender accum )
215 [ length ] keep (appender-for) ; inline
217 : appender ( quot -- appender accum )
218 V{ } appender-for ; inline
220 : map-concat-as ( ... seq quot: ( ... elt -- ... newelt ) exemplar -- ... newseq )
221 [ appender-for [ each ] dip ] keep like ; inline
223 : >resizable ( seq -- accum ) ! fixes map-concat "cannot apply call to run-time..."
224 [ length ] keep [ new-resizable ] [ append! ] bi ;
226 : map-concat ( ... seq quot: ( ... elt -- ... newelt ) -- ... newseq )
227 over empty? [ 2drop { } ] [
228 [ [ first ] dip call ] 2keep rot [
229 >resizable [ '[ @ _ push-all ] 1 each-from ] keep
233 : map-filter-as ( ... seq map-quot: ( ... elt -- ... newelt ) filter-quot: ( ... newelt -- ... ? ) exemplar -- ... subseq )
235 [ (selector-as) [ compose each ] dip ] 2curry dip like ; inline
237 : map-filter ( ... seq map-quot: ( ... elt -- ... newelt ) filter-quot: ( ... newelt -- ... ? ) -- ... subseq )
238 pick map-filter-as ; inline
240 : map-sift ( ... seq quot: ( ... elt -- ... newelt ) -- ... newseq )
241 [ ] map-filter ; inline
243 : map-harvest ( ... seq quot: ( ... elt -- ... newelt ) -- ... newseq )
244 [ empty? not ] map-filter ; inline
248 : (setup-each-from) ( i seq -- n quot )
249 [ length over [-] swap ] keep '[ _ + _ nth-unsafe ] ; inline
251 : setup-each-from ( i seq quot -- n quot' )
252 [ (setup-each-from) ] dip compose ; inline
256 : map-from-as ( ... seq quot: ( ... elt -- ... newelt ) i exemplar -- ... newseq )
257 [ -rot setup-each-from ] dip map-integers ; inline
259 : map-from ( ... seq quot: ( ... elt -- ... newelt ) i -- ... newseq )
260 pick map-from-as ; inline
264 : push-map-if ( ..a elt filter-quot: ( ..a elt -- ..b ? ) map-quot: ( ..a elt -- ..b newelt ) accum -- ..b )
265 [ keep over ] 2dip [ when ] dip rot [ push ] [ 2drop ] if ; inline
267 : (filter-mapper-for) ( filter-quot map-quot length exempler -- filter-mapper accum )
268 new-resizable [ [ push-map-if ] 3curry ] keep ; inline
270 : filter-mapper-for ( filter-quot map-quot exemplar -- filter-mapper accum )
271 [ length ] keep (filter-mapper-for) ; inline
273 : filter-mapper ( filter-quot map-quot -- filter-mapper accum )
274 V{ } filter-mapper-for ; inline
278 : filter-map-as ( ... seq filter-quot: ( ... elt -- ... ? ) map-quot: ( ... elt -- ... newelt ) exemplar -- ... newseq )
280 [ (filter-mapper-for) [ each ] dip ] 2curry dip like ; inline
282 : filter-map ( ... seq filter-quot: ( ... elt -- ... ? ) map-quot: ( ... elt -- ... newelt ) -- ... newseq )
283 pick filter-map-as ; inline
285 : 2map-sum ( ... seq1 seq2 quot: ( ... elt1 elt2 -- ... n ) -- ... n )
286 [ 0 ] 3dip [ dip + ] curry [ rot ] prepose 2each ; inline
288 : 2count ( ... seq1 seq2 quot: ( ... elt1 elt2 -- ... ? ) -- ... n )
289 [ 1 0 ? ] compose 2map-sum ; inline
292 ( ... seq1 seq2 seq3 quot: ( ... elt1 elt2 elt3 -- ... ) i -- ... )
293 [ (3each) ] dip -rot (each-integer) ; inline
296 ( ..a seq1 seq2 seq3 map-quot: ( ..a elt1 elt2 elt3 -- ..b intermediate ) reduce-quot: ( ..b prev intermediate -- ..a next ) -- ..a result )
297 [ [ [ [ first ] tri@ ] 3keep ] dip [ 3dip ] keep ] dip compose 1 3each-from ; inline
299 : round-robin ( seq -- newseq )
301 [ longest length <iota> ] keep
302 [ [ ?nth ] with map ] curry map concat sift
305 : sift-as ( seq exemplar -- newseq )
308 : sift! ( seq -- newseq )
311 : harvest-as ( seq exemplar -- newseq )
312 [ empty? not ] swap filter-as ;
314 : harvest! ( seq -- newseq )
317 : head-as ( seq n exemplar -- seq' )
318 [ head-slice ] [ like ] bi* ; inline
320 : head*-as ( seq n exemplar -- seq' )
321 [ head-slice* ] [ like ] bi* ; inline
323 : tail-as ( seq n exemplar -- seq' )
324 [ tail-slice ] [ like ] bi* ; inline
326 : tail*-as ( seq n exemplar -- seq' )
327 [ tail-slice* ] [ like ] bi* ; inline
329 : trim-as ( ... seq quot: ( ... elt -- ... ? ) exemplar -- ... newseq )
330 [ trim-slice ] [ like ] bi* ; inline
332 : ?trim ( seq quot: ( elt -- ? ) -- seq/newseq )
333 over empty? [ drop ] [
334 over [ first-unsafe ] [ last-unsafe ] bi pick either?
338 : ?trim-head ( seq quot: ( elt -- ? ) -- seq/newseq )
339 over empty? [ drop ] [
340 over first-unsafe over call
341 [ trim-head ] [ drop ] if
344 : ?trim-tail ( seq quot: ( elt -- ? ) -- seq/newseq )
345 over empty? [ drop ] [
346 over last-unsafe over call
347 [ trim-tail ] [ drop ] if
350 : unsurround ( newseq seq2 seq3 -- seq1 )
351 [ ?head drop ] [ ?tail drop ] bi* ;
353 : >string-list ( seq -- seq' )
354 [ "\"" 1surround ] map "," join ;
356 : one? ( ... seq quot: ( ... elt -- ... ? ) -- ... ? )
358 [ 1 + ] 2dip find-from drop not
359 ] [ 3drop f ] if ; inline
361 : map-index! ( ... seq quot: ( ... elt index -- ... newelt ) -- ... seq )
362 over [ [ (each-index) ] dip collect ] keep ; inline
366 : (2each-index) ( seq1 seq2 quot -- n quot' )
367 [ setup-2each [ keep ] curry ] dip compose ; inline
371 : 2each-index ( ... seq1 seq2 quot: ( ... elt1 elt2 index -- ... ) -- ... )
372 (2each-index) each-integer ; inline
374 : 2map-into ( seq1 seq2 quot into -- )
375 [ (2each) ] dip collect ; inline
377 : 2map! ( ... seq1 seq2 quot: ( ... elt1 elt2 -- ... newelt ) -- ... seq1 )
378 pick [ 2map-into ] keep ; inline
380 : 2map-index ( ... seq1 seq2 quot: ( ... elt1 elt2 index -- ... newelt ) -- ... newseq )
381 pick [ (2each-index) ] dip map-integers ; inline
383 TUPLE: evens { seq read-only } ;
387 M: evens length seq>> length 1 + 2/ ; inline
389 M: evens virtual@ [ 2 * ] [ seq>> ] bi* ; inline
391 M: evens virtual-exemplar seq>> ; inline
393 INSTANCE: evens virtual-sequence
395 TUPLE: odds { seq read-only } ;
399 M: odds length seq>> length 2/ ; inline
401 M: odds virtual@ [ 2 * 1 + ] [ seq>> ] bi* ; inline
403 M: odds virtual-exemplar seq>> ; inline
405 INSTANCE: odds virtual-sequence
407 : until-empty ( seq quot -- )
408 [ dup empty? ] swap until drop ; inline
410 : arg-max ( seq -- n )
411 [ supremum ] keep index ;
413 : arg-min ( seq -- n )
414 [ infimum ] keep index ;
418 : push-index-if ( ..a elt i quot: ( ..a elt -- ..b ? ) accum -- ..b )
419 [ dip ] dip rot [ push ] [ 2drop ] if ; inline
423 : arg-where ( ... seq quot: ( ... elt -- ... ? ) -- ... indices )
424 over length <vector> [
425 [ push-index-if ] 2curry each-index
428 : arg-sort ( seq -- indices )
429 zip-index sort-keys values ;
431 : first= ( seq elt -- ? ) [ first ] dip = ; inline
432 : second= ( seq elt -- ? ) [ second ] dip = ; inline
433 : third= ( seq elt -- ? ) [ third ] dip = ; inline
434 : fourth= ( seq elt -- ? ) [ fourth ] dip = ; inline
435 : last= ( seq elt -- ? ) [ last ] dip = ; inline
436 : nth= ( n seq elt -- ? ) [ nth ] dip = ; inline
438 : first? ( ... seq quot: ( ... elt -- ... ? ) -- ... ? ) [ first ] dip call ; inline
439 : second? ( ... seq quot: ( ... elt -- ... ? ) -- ... ? ) [ second ] dip call ; inline
440 : third? ( ... seq quot: ( ... elt -- ... ? ) -- ... ? ) [ third ] dip call ; inline
441 : fourth? ( ... seq quot: ( ... elt -- ... ? ) -- ... ? ) [ fourth ] dip call ; inline
442 : last? ( ... seq quot: ( ... elt -- ... ? ) -- ... ? ) [ last ] dip call ; inline
443 : nth? ( ... n seq quot: ( ... elt -- ... ? ) -- ... ? ) [ nth ] dip call ; inline
445 : loop>sequence** ( ... quot: ( ... -- ... obj ? ) exemplar -- ... seq )
446 [ ] swap produce-as nip ; inline
448 : loop>array** ( ... quot: ( ... -- ... obj ? ) -- ... array )
449 { } loop>sequence** ; inline
451 : loop>sequence* ( ... quot: ( ... -- ... obj ? ) exemplar -- ... seq )
452 [ t ] [ '[ [ _ dip ] [ f f f ] if* ] [ swap ] ] [ produce-as 2nip ] tri* ; inline
454 : loop>array* ( ... quot: ( ... -- ... obj ? ) -- ... array )
455 { } loop>sequence* ; inline
457 : loop>sequence ( ... quot: ( ... -- ... obj/f ) exemplar -- ... seq )
458 [ [ dup ] compose [ ] ] dip produce-as nip ; inline
460 : loop>array ( ... quot: ( ... -- ... obj/f ) -- ... array )
461 { } loop>sequence ; inline
463 : zero-loop>sequence ( ... quot: ( ... n -- ... obj/f ) exemplar -- ... seq )
464 [ 0 ] [ '[ _ keep 1 + swap ] ] [ loop>sequence ] tri* nip ; inline
466 : zero-loop>array ( quot: ( ..a n -- ..a obj ) -- seq )
467 { } zero-loop>sequence ; inline
471 : (reverse) ( seq -- newseq )
472 dup [ length ] keep new-sequence
473 [ 0 swap copy-unsafe ] keep reverse! ;
477 : reverse-as ( seq exemplar -- newseq )
478 [ (reverse) ] [ like ] bi* ;
480 : map-product ( ... seq quot: ( ... elt -- ... n ) -- ... n )
481 [ 1 ] 2dip [ dip * ] curry [ swap ] prepose each ; inline
483 : insert-nth! ( elt n seq -- )
484 [ length ] keep ensure swap pick (a..b]
485 over '[ [ 1 + ] keep _ move-unsafe ] each
488 : set-nths ( value indices seq -- )
489 swapd '[ _ swap _ set-nth ] each ; inline
491 : set-nths-unsafe ( value indices seq -- )
492 swapd '[ _ swap _ set-nth-unsafe ] each ; inline
496 : (map-find-index) ( seq quot find-quot -- result i elt )
497 [ [ f ] 2dip [ [ nip ] 2dip call dup ] curry ] dip call
498 [ [ [ drop f ] unless ] keep ] dip ; inline
502 : map-find-index ( ... seq quot: ( ... elt index -- ... result/f ) -- ... result i elt )
503 [ find-index ] (map-find-index) ; inline
505 : filter-length ( seq n -- seq' ) '[ length _ = ] filter ;
507 : all-shortest ( seqs -- seqs' ) dup shortest length filter-length ;
509 : all-longest ( seqs -- seqs' ) dup longest length filter-length ;
511 : remove-first ( obj seq -- seq' )
512 [ index ] keep over [ remove-nth ] [ nip ] if ;
514 : remove-first! ( obj seq -- seq )
515 [ index ] keep over [ remove-nth! ] [ nip ] if ;
517 : remove-last ( obj seq -- seq' )
518 [ last-index ] keep over [ remove-nth ] [ nip ] if ;
520 : remove-last! ( obj seq -- seq )
521 [ last-index ] keep over [ remove-nth! ] [ nip ] if ;
523 : ?first2 ( seq -- first/f second/f )
526 { 1 [ first-unsafe f ] }
527 [ drop first2-unsafe ]
530 : ?first3 ( seq -- first/f second/f third/f )
533 { 1 [ first-unsafe f f ] }
534 { 2 [ first2-unsafe f ] }
535 [ drop first3-unsafe ]
538 : ?first4 ( seq -- first/f second/f third/f fourth/f )
540 { 0 [ drop f f f f ] }
541 { 1 [ first-unsafe f f f ] }
542 { 2 [ first2-unsafe f f ] }
543 { 3 [ first3-unsafe f ] }
544 [ drop first4-unsafe ]
547 : cut-when ( ... seq quot: ( ... elt -- ... ? ) -- ... before after )
548 [ find drop ] keepd swap
549 [ cut ] [ f over like ] if* ; inline
551 : nth* ( n seq -- elt )
552 [ length 1 - swap - ] [ nth ] bi ; inline
554 : each-index-from ( ... seq quot: ( ... elt index -- ... ) i -- ... )
555 -rot (each-index) (each-integer) ; inline
559 : select-by* ( ... seq quot: ( ... elt -- ... x ) compare: ( obj1 obj2 -- ? ) -- ... i elt )
561 [ keep swap ] curry [ dip ] curry
562 [ [ first 0 ] dip call ] 2keep
563 [ 2curry 3dip 5 npick pick ] curry
565 [ [ 3drop ] [ [ 3drop ] 3dip ] if ] compose
566 ] bi* compose 1 each-index-from nip swap ; inline
570 : supremum-by* ( ... seq quot: ( ... elt -- ... x ) -- ... i elt )
571 [ after? ] select-by* ; inline
573 : infimum-by* ( ... seq quot: ( ... elt -- ... x ) -- ... i elt )
574 [ before? ] select-by* ; inline
576 : ?supremum ( seq/f -- elt/f )
578 [ ] [ 2dup and [ max ] [ dupd ? ] if ] map-reduce
581 : ?infimum ( seq/f -- elt/f )
583 [ ] [ 2dup and [ min ] [ dupd ? ] if ] map-reduce
586 : change-last ( seq quot -- )
587 [ drop length 1 - ] [ change-nth ] 2bi ; inline
589 : change-last-unsafe ( seq quot -- )
590 [ drop length 1 - ] [ change-nth-unsafe ] 2bi ; inline
592 : replicate-into ( ... seq quot: ( ... -- ... newelt ) -- ... )
593 over [ length ] 2dip '[ _ dip _ set-nth-unsafe ] each-integer ; inline
595 : count* ( ... seq quot: ( ... elt -- ... ? ) -- ... % )
596 over [ count ] [ length ] bi* / ; inline
598 : find-last-index ( ... seq quot: ( ... elt i -- ... ? ) -- ... i elt )
599 [ [ 1 - ] dip find-last-integer ] (find-index) ; inline
601 : map-find-last-index ( ... seq quot: ( ... elt index -- ... result/f ) -- ... result i elt )
602 [ find-last-index ] (map-find-index) ; inline
604 :: (start-all) ( seq subseq increment -- indices )
606 [ [ subseq seq ] dip subseq-start-from dup ]
607 [ [ increment + ] keep ] produce nip ;
609 : start-all ( seq subseq -- indices )
610 dup length (start-all) ; inline
612 : start-all* ( seq subseq -- indices )
613 1 (start-all) ; inline
615 : count-subseq ( seq subseq -- n )
616 start-all length ; inline
618 : count-subseq* ( seq subseq -- n )
619 start-all* length ; inline
621 : assoc-zip-with ( quot: ( key value -- calc ) -- alist )
622 '[ _ 2keep 2array swap ] assoc-map ; inline
624 : take-while ( ... seq quot: ( ... elt -- ... ? ) -- head-slice )
625 [ '[ @ not ] find drop ] keepd swap
626 [ dup length ] unless* head-slice ; inline
628 : drop-while ( ... seq quot: ( ... elt -- ... ? ) -- tail-slice )
629 [ '[ @ not ] find drop ] keepd swap
630 [ dup length ] unless* tail-slice ; inline
632 : count-head ( seq quot -- n )
633 [ not ] compose [ find drop ] keepd length or ; inline
635 : count-tail ( seq quot -- n )
636 [ not ] compose [ find-last drop ] keepd
637 length swap [ - 1 - ] when* ; inline
639 :: interleaved-as ( seq glue exemplar -- newseq )
640 seq length dup 1 - + 0 max exemplar new-sequence :> newseq
641 seq [ 2 * newseq set-nth-unsafe ] each-index
642 seq length 1 - [ 2 * 1 + glue swap newseq set-nth-unsafe ] each-integer
645 : interleaved ( seq glue -- newseq )
646 over interleaved-as ;
648 : extract! ( ... seq quot: ( ... elt -- ... ? ) -- ... seq )
649 [ dup ] compose over [ length ] keep new-resizable
650 [ [ push-if ] 2curry reject! ] keep swap like ; inline
652 : find-pred-loop ( ... i n seq quot: ( ... elt -- ... calc ? ) -- ... calc/f i/f elt/f )
656 [ [ 3drop ] 2dip rot ]
657 [ 2drop [ 1 + ] 3dip find-pred-loop ] if
660 ] if ; inline recursive
662 : find-pred ( ... seq quot: ( ... elt -- ... calc ) pred: ( ... calc -- ... ? ) -- ... calc/f i/f elt/f )
664 [ [ length check-length ] keep ] 2dip
665 '[ nth-unsafe _ keep swap _ keep swap ] find-pred-loop swapd ; inline
667 ! https://en.wikipedia.org/wiki/Maximum_subarray_problem
668 ! Kadane's algorithm O(n) largest sum in subarray
669 : max-subarray-sum ( seq -- sum )
671 [ [ + ] keep max [ max ] keep ] each drop ;