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* [ 0 len clamp ] bi@ dupd max seq subseq ;
17 : safe-subseq ( from to seq -- subseq )
18 [ length '[ 0 _ clamp ] bi@ ] keep subseq ;
20 : all-subseqs ( seq -- seqs )
21 dup length [1..b] [ clump ] with map concat ;
23 :: each-subseq ( ... seq quot: ( ... subseq -- ... ) -- ... )
26 from len (a..b] [| to |
27 from to seq subseq quot call
31 : map-like ( seq exemplar -- seq' )
32 '[ _ like ] map ; inline
34 : filter-all-subseqs-range ( ... seq range quot: ( ... subseq -- ... ? ) -- seq )
36 '[ <clumps> _ filter ] with map concat
37 ] keepdd map-like ; inline
39 : filter-all-subseqs ( ... seq quot: ( ... subseq -- ... ? ) -- seq )
40 [ dup length [1..b] ] dip filter-all-subseqs-range ; inline
42 :: longest-subseq ( seq1 seq2 -- subseq )
47 len1 1 + [ len2 1 + 0 <array> ] replicate :> table
51 y 1 - seq2 nth-unsafe = [
52 y 1 - x 1 - table nth-unsafe nth-unsafe 1 + :> len
53 len y x table nth-unsafe set-nth-unsafe
54 len n > [ len n! x end! ] when
55 ] [ 0 y x table nth-unsafe set-nth-unsafe ] if
57 ] each end n - end seq1 subseq ;
59 : pad-longest ( seq1 seq2 elt -- seq1 seq2 )
60 [ 2dup max-length ] dip [ pad-tail ] 2curry bi@ ;
62 : pad-center ( seq n elt -- padded )
63 swap pick length [-] [ drop ] [
64 [ 2/ ] [ over - ] bi rot '[ _ <repetition> ] bi@
68 : change-nths ( ... indices seq quot: ( ... elt -- ... elt' ) -- ... )
69 [ change-nth ] 2curry each ; inline
71 : push-if-index ( ..a elt i quot: ( ..a elt i -- ..b ? ) accum -- ..b )
72 [ keepd ] dip rot [ push ] [ 2drop ] if ; inline
74 : push-if* ( ..a elt quot: ( ..a elt -- ..b obj/f ) accum -- ..b )
75 [ call ] dip [ push ] [ drop ] if* ; inline
79 : (index-selector-as) ( quot length exampler -- selector accum )
80 new-resizable [ [ push-if-index ] 2curry ] keep ; inline
82 : (selector-as*) ( quot length exemplar -- selector accum )
83 new-resizable [ [ push-if* ] 2curry ] keep ; inline
87 : index-selector-as ( quot exemplar -- selector accum )
88 [ length ] keep (index-selector-as) ; inline
90 : index-selector ( quot -- selector accum )
91 V{ } index-selector-as ; inline
93 : selector-as* ( quot exemplar -- selector accum )
94 [ length ] keep (selector-as*) ; inline
96 : selector* ( quot -- selector accum ) V{ } selector-as* ; inline
98 : filter-index-as ( ... seq quot: ( ... elt i -- ... ? ) exemplar -- ... seq' )
99 pick length over [ (index-selector-as) [ each-index ] dip ] 2curry dip like ; inline
101 : filter-index ( ... seq quot: ( ... elt i -- ... ? ) -- ... seq' )
102 over filter-index-as ; inline
104 : even-indices ( seq -- seq' )
105 [ length 1 + 2/ ] keep [
106 [ [ 2 * ] dip nth-unsafe ] curry
107 ] keep map-integers ;
109 : odd-indices ( seq -- seq' )
111 [ [ 2 * 1 + ] dip nth-unsafe ] curry
112 ] keep map-integers ;
114 : compact ( ... seq quot: ( ... elt -- ... ? ) elt -- ... seq' )
115 [ split-when harvest ] dip join ; inline
117 : collapse ( ... seq quot: ( ... elt -- ... ? ) elt -- ... seq' )
119 [ [ harvest ] dip join ]
120 [ [ first empty? ] dip [ prepend ] curry when ]
121 [ [ last empty? ] dip [ append ] curry when ]
124 :: slice-when ( seq quot: ( elt -- ? ) -- seq' )
127 dup seq quot find-from drop
128 [ 2dup = [ 1 + ] when ] [ len ] if*
129 [ seq <slice> ] keep len or swap
130 ] produce nip ; inline
132 : ?<slice> ( from/f to/f sequence -- slice )
133 [ [ 0 ] unless* ] 2dip
134 over [ nip [ length ] [ ] bi ] unless
137 : sequence>slice ( sequence -- slice )
138 [ drop 0 ] [ length ] [ ] tri <slice> ; inline
140 : slice-order-by-from ( slice1 slice2 -- slice-lt slice-gt )
141 2dup [ from>> ] bi@ > [ swap ] when ; inline
143 : ordered-slices-range ( slice-lt slice-gt -- to from )
144 [ to>> ] [ from>> ] bi* ;
146 : unordered-slices-range ( slice1 slice2 -- to from )
147 slice-order-by-from ordered-slices-range ;
149 : ordered-slices-overlap? ( slice-lt slice-gt -- ? )
150 ordered-slices-range > ; inline
152 : unordered-slices-overlap? ( slice1 slice2 -- ? )
153 unordered-slices-range > ; inline
155 : slices-overlap? ( slice1 slice2 -- ? )
156 unordered-slices-overlap? ;
158 : ordered-slices-touch? ( slice-lt slice-gt -- ? )
159 ordered-slices-range >= ; inline
161 : unordered-slices-touch? ( slice1 slice2 -- ? )
162 unordered-slices-range >= ; inline
164 : slices-touch? ( slice1 slice2 -- ? )
165 unordered-slices-touch? ;
167 ERROR: slices-don't-touch slice1 slice2 ;
169 : merge-slices ( slice1 slice2 -- slice/* )
171 2dup ordered-slices-touch? [
172 [ from>> ] [ [ to>> ] [ seq>> ] bi ] bi* <slice>
177 : rotate ( seq n -- seq' )
178 over length mod dup 0 >= [ cut ] [ abs cut* ] if prepend ;
180 ERROR: underlying-mismatch slice1 slice2 ;
182 : ensure-same-underlying ( slice1 slice2 -- slice1 slice2 )
183 2dup [ seq>> ] bi@ eq? [ underlying-mismatch ] unless ;
185 : span-slices ( slice1 slice2 -- slice )
186 ensure-same-underlying
187 [ [ from>> ] bi@ min ]
189 [ drop seq>> ] 2tri <slice> ;
191 : ?span-slices ( slice1/f slice2/f -- slice )
192 2dup and [ span-slices ] [ or ] if ;
194 :: rotate! ( seq n -- )
196 n len mod dup 0 < [ len + ] when seq bounds-check drop 0 over
198 [ seq exchange-unsafe ] [ [ 1 + ] bi@ ] 2bi
199 dup len = [ drop over ] when
200 2over = [ -rot nip over ] when
203 : all-rotations ( seq -- seq' )
204 dup length <iota> [ rotate ] with map ;
208 : (appender-for) ( quot length exemplar -- appender accum )
209 new-resizable [ [ push-all ] curry compose ] keep ; inline
213 : appender-for ( quot exemplar -- appender accum )
214 [ length ] keep (appender-for) ; inline
216 : appender ( quot -- appender accum )
217 V{ } appender-for ; inline
219 : map-concat-as ( ... seq quot: ( ... elt -- ... newelt ) exemplar -- ... newseq )
220 [ appender-for [ each ] dip ] keep like ; inline
222 : >resizable ( seq -- accum ) ! fixes map-concat "cannot apply call to run-time..."
223 [ length ] keep [ new-resizable ] [ append! ] bi ;
225 : map-concat ( ... seq quot: ( ... elt -- ... newelt ) -- ... newseq )
226 over empty? [ 2drop { } ] [
227 [ [ first ] dip call ] 2keep rot [
228 >resizable [ '[ @ _ push-all ] 1 each-from ] keep
232 : map-filter-as ( ... seq map-quot: ( ... elt -- ... newelt ) filter-quot: ( ... newelt -- ... ? ) exemplar -- ... subseq )
234 [ (selector-as) [ compose each ] dip ] 2curry dip like ; inline
236 : map-filter ( ... seq map-quot: ( ... elt -- ... newelt ) filter-quot: ( ... newelt -- ... ? ) -- ... subseq )
237 pick map-filter-as ; inline
239 : map-sift ( ... seq quot: ( ... elt -- ... newelt ) -- ... newseq )
240 [ ] map-filter ; inline
242 : map-harvest ( ... seq quot: ( ... elt -- ... newelt ) -- ... newseq )
243 [ empty? not ] map-filter ; inline
247 : (setup-each-from) ( i seq -- n quot )
248 [ length over [-] swap ] keep '[ _ + _ nth-unsafe ] ; inline
250 : setup-each-from ( i seq quot -- n quot' )
251 [ (setup-each-from) ] dip compose ; inline
255 : map-from-as ( ... seq quot: ( ... elt -- ... newelt ) i exemplar -- ... newseq )
256 [ -rot setup-each-from ] dip map-integers ; inline
258 : map-from ( ... seq quot: ( ... elt -- ... newelt ) i -- ... newseq )
259 pick map-from-as ; inline
263 : push-map-if ( ..a elt filter-quot: ( ..a elt -- ..b ? ) map-quot: ( ..a elt -- ..b newelt ) accum -- ..b )
264 [ keep over ] 2dip [ when ] dip rot [ push ] [ 2drop ] if ; inline
266 : (filter-mapper-for) ( filter-quot map-quot length exempler -- filter-mapper accum )
267 new-resizable [ [ push-map-if ] 3curry ] keep ; inline
269 : filter-mapper-for ( filter-quot map-quot exemplar -- filter-mapper accum )
270 [ length ] keep (filter-mapper-for) ; inline
272 : filter-mapper ( filter-quot map-quot -- filter-mapper accum )
273 V{ } filter-mapper-for ; inline
277 : filter-map-as ( ... seq filter-quot: ( ... elt -- ... ? ) map-quot: ( ... elt -- ... newelt ) exemplar -- ... newseq )
279 [ (filter-mapper-for) [ each ] dip ] 2curry dip like ; inline
281 : filter-map ( ... seq filter-quot: ( ... elt -- ... ? ) map-quot: ( ... elt -- ... newelt ) -- ... newseq )
282 pick filter-map-as ; inline
284 : 2map-sum ( ... seq1 seq2 quot: ( ... elt1 elt2 -- ... n ) -- ... n )
285 [ 0 ] 3dip [ dip + ] curry [ rot ] prepose 2each ; inline
287 : 2count ( ... seq1 seq2 quot: ( ... elt1 elt2 -- ... ? ) -- ... n )
288 [ 1 0 ? ] compose 2map-sum ; inline
291 ( ... seq1 seq2 seq3 quot: ( ... elt1 elt2 elt3 -- ... ) i -- ... )
292 [ (3each) ] dip -rot (each-integer) ; inline
295 ( ..a seq1 seq2 seq3 map-quot: ( ..a elt1 elt2 elt3 -- ..b intermediate ) reduce-quot: ( ..b prev intermediate -- ..a next ) -- ..a result )
296 [ [ [ [ first ] tri@ ] 3keep ] dip [ 3dip ] keep ] dip compose 1 3each-from ; inline
298 : round-robin ( seq -- newseq )
300 [ longest length <iota> ] keep
301 [ [ ?nth ] with map ] curry map concat sift
304 : sift-as ( seq exemplar -- newseq )
307 : sift! ( seq -- newseq )
310 : harvest-as ( seq exemplar -- newseq )
311 [ empty? not ] swap filter-as ;
313 : harvest! ( seq -- newseq )
316 : head-as ( seq n exemplar -- seq' )
317 [ head-slice ] [ like ] bi* ; inline
319 : head*-as ( seq n exemplar -- seq' )
320 [ head-slice* ] [ like ] bi* ; inline
322 : tail-as ( seq n exemplar -- seq' )
323 [ tail-slice ] [ like ] bi* ; inline
325 : tail*-as ( seq n exemplar -- seq' )
326 [ tail-slice* ] [ like ] bi* ; inline
328 : trim-as ( ... seq quot: ( ... elt -- ... ? ) exemplar -- ... newseq )
329 [ trim-slice ] [ like ] bi* ; inline
331 : ?trim ( seq quot: ( elt -- ? ) -- seq/newseq )
332 over empty? [ drop ] [
333 over [ first-unsafe ] [ last-unsafe ] bi pick either?
337 : ?trim-head ( seq quot: ( elt -- ? ) -- seq/newseq )
338 over empty? [ drop ] [
339 over first-unsafe over call
340 [ trim-head ] [ drop ] if
343 : ?trim-tail ( seq quot: ( elt -- ? ) -- seq/newseq )
344 over empty? [ drop ] [
345 over last-unsafe over call
346 [ trim-tail ] [ drop ] if
349 : unsurround ( newseq seq2 seq3 -- seq1 )
350 [ ?head drop ] [ ?tail drop ] bi* ;
352 : >string-list ( seq -- seq' )
353 [ "\"" 1surround ] map "," join ;
355 : one? ( ... seq quot: ( ... elt -- ... ? ) -- ... ? )
357 [ 1 + ] 2dip find-from drop not
358 ] [ 3drop f ] if ; inline
360 : map-index! ( ... seq quot: ( ... elt index -- ... newelt ) -- ... seq )
361 over [ [ (each-index) ] dip collect ] keep ; inline
365 : (2each-index) ( seq1 seq2 quot -- n quot' )
366 [ setup-2each [ keep ] curry ] dip compose ; inline
370 : 2each-index ( ... seq1 seq2 quot: ( ... elt1 elt2 index -- ... ) -- ... )
371 (2each-index) each-integer ; inline
373 : 2map-into ( seq1 seq2 quot into -- )
374 [ (2each) ] dip collect ; inline
376 : 2map! ( ... seq1 seq2 quot: ( ... elt1 elt2 -- ... newelt ) -- ... seq1 )
377 pick [ 2map-into ] keep ; inline
379 : 2map-index ( ... seq1 seq2 quot: ( ... elt1 elt2 index -- ... newelt ) -- ... newseq )
380 pick [ (2each-index) ] dip map-integers ; inline
382 TUPLE: evens { seq read-only } ;
386 M: evens length seq>> length 1 + 2/ ; inline
388 M: evens virtual@ [ 2 * ] [ seq>> ] bi* ; inline
390 M: evens virtual-exemplar seq>> ; inline
392 INSTANCE: evens virtual-sequence
394 TUPLE: odds { seq read-only } ;
398 M: odds length seq>> length 2/ ; inline
400 M: odds virtual@ [ 2 * 1 + ] [ seq>> ] bi* ; inline
402 M: odds virtual-exemplar seq>> ; inline
404 INSTANCE: odds virtual-sequence
406 : until-empty ( seq quot -- )
407 [ dup empty? ] swap until drop ; inline
409 : arg-max ( seq -- n )
410 [ supremum ] keep index ;
412 : arg-min ( seq -- n )
413 [ infimum ] keep index ;
417 : push-index-if ( ..a elt i quot: ( ..a elt -- ..b ? ) accum -- ..b )
418 [ dip ] dip rot [ push ] [ 2drop ] if ; inline
422 : arg-where ( ... seq quot: ( ... elt -- ... ? ) -- ... indices )
423 over length <vector> [
424 [ push-index-if ] 2curry each-index
427 : arg-sort ( seq -- indices )
428 zip-index sort-keys values ;
430 : first= ( seq elt -- ? ) [ first ] dip = ; inline
431 : second= ( seq elt -- ? ) [ second ] dip = ; inline
432 : third= ( seq elt -- ? ) [ third ] dip = ; inline
433 : fourth= ( seq elt -- ? ) [ fourth ] dip = ; inline
434 : last= ( seq elt -- ? ) [ last ] dip = ; inline
435 : nth= ( n seq elt -- ? ) [ nth ] dip = ; inline
437 : first? ( ... seq quot: ( ... elt -- ... ? ) -- ... ? ) [ first ] dip call ; inline
438 : second? ( ... seq quot: ( ... elt -- ... ? ) -- ... ? ) [ second ] dip call ; inline
439 : third? ( ... seq quot: ( ... elt -- ... ? ) -- ... ? ) [ third ] dip call ; inline
440 : fourth? ( ... seq quot: ( ... elt -- ... ? ) -- ... ? ) [ fourth ] dip call ; inline
441 : last? ( ... seq quot: ( ... elt -- ... ? ) -- ... ? ) [ last ] dip call ; inline
442 : nth? ( ... n seq quot: ( ... elt -- ... ? ) -- ... ? ) [ nth ] dip call ; inline
444 : loop>sequence** ( ... quot: ( ... -- ... obj ? ) exemplar -- ... seq )
445 [ ] swap produce-as nip ; inline
447 : loop>array** ( ... quot: ( ... -- ... obj ? ) -- ... array )
448 { } loop>sequence** ; inline
450 : loop>sequence* ( ... quot: ( ... -- ... obj ? ) exemplar -- ... seq )
451 [ t ] [ '[ [ _ dip ] [ f f f ] if* ] [ swap ] ] [ produce-as 2nip ] tri* ; inline
453 : loop>array* ( ... quot: ( ... -- ... obj ? ) -- ... array )
454 { } loop>sequence* ; inline
456 : loop>sequence ( ... quot: ( ... -- ... obj/f ) exemplar -- ... seq )
457 [ [ dup ] compose [ ] ] dip produce-as nip ; inline
459 : loop>array ( ... quot: ( ... -- ... obj/f ) -- ... array )
460 { } loop>sequence ; inline
462 : zero-loop>sequence ( ... quot: ( ... n -- ... obj/f ) exemplar -- ... seq )
463 [ 0 ] [ '[ _ keep 1 + swap ] ] [ loop>sequence ] tri* nip ; inline
465 : zero-loop>array ( quot: ( ..a n -- ..a obj ) -- seq )
466 { } zero-loop>sequence ; inline
470 : (reverse) ( seq -- newseq )
471 dup [ length ] keep new-sequence
472 [ 0 swap copy-unsafe ] keep reverse! ;
476 : reverse-as ( seq exemplar -- newseq )
477 [ (reverse) ] [ like ] bi* ;
479 : map-product ( ... seq quot: ( ... elt -- ... n ) -- ... n )
480 [ 1 ] 2dip [ dip * ] curry [ swap ] prepose each ; inline
482 : insert-nth! ( elt n seq -- )
483 [ length ] keep ensure swap pick (a..b]
484 over '[ [ 1 + ] keep _ move-unsafe ] each
487 : set-nths ( value indices seq -- )
488 swapd '[ _ swap _ set-nth ] each ; inline
490 : set-nths-unsafe ( value indices seq -- )
491 swapd '[ _ swap _ set-nth-unsafe ] each ; inline
495 : (map-find-index) ( seq quot find-quot -- result i elt )
496 [ [ f ] 2dip [ [ nip ] 2dip call dup ] curry ] dip call
497 [ [ [ drop f ] unless ] keep ] dip ; inline
501 : map-find-index ( ... seq quot: ( ... elt index -- ... result/f ) -- ... result i elt )
502 [ find-index ] (map-find-index) ; inline
504 : filter-length ( seq n -- seq' ) '[ length _ = ] filter ;
506 : all-shortest ( seqs -- seqs' ) dup shortest length filter-length ;
508 : all-longest ( seqs -- seqs' ) dup longest length filter-length ;
510 : remove-first ( obj seq -- seq' )
511 [ index ] keep over [ remove-nth ] [ nip ] if ;
513 : remove-first! ( obj seq -- seq )
514 [ index ] keep over [ remove-nth! ] [ nip ] if ;
516 : remove-last ( obj seq -- seq' )
517 [ last-index ] keep over [ remove-nth ] [ nip ] if ;
519 : remove-last! ( obj seq -- seq )
520 [ last-index ] keep over [ remove-nth! ] [ nip ] if ;
522 : ?first2 ( seq -- first/f second/f )
525 { 1 [ first-unsafe f ] }
526 [ drop first2-unsafe ]
529 : ?first3 ( seq -- first/f second/f third/f )
532 { 1 [ first-unsafe f f ] }
533 { 2 [ first2-unsafe f ] }
534 [ drop first3-unsafe ]
537 : ?first4 ( seq -- first/f second/f third/f fourth/f )
539 { 0 [ drop f f f f ] }
540 { 1 [ first-unsafe f f f ] }
541 { 2 [ first2-unsafe f f ] }
542 { 3 [ first3-unsafe f ] }
543 [ drop first4-unsafe ]
546 : cut-when ( ... seq quot: ( ... elt -- ... ? ) -- ... before after )
547 [ find drop ] keepd swap
548 [ cut ] [ f over like ] if* ; inline
550 : nth* ( n seq -- elt )
551 [ length 1 - swap - ] [ nth ] bi ; inline
553 : each-index-from ( ... seq quot: ( ... elt index -- ... ) i -- ... )
554 -rot (each-index) (each-integer) ; inline
558 : select-by* ( ... seq quot: ( ... elt -- ... x ) compare: ( obj1 obj2 -- ? ) -- ... i elt )
560 [ keep swap ] curry [ dip ] curry
561 [ [ first 0 ] dip call ] 2keep
562 [ 2curry 3dip 5 npick pick ] curry
564 [ [ 3drop ] [ [ 3drop ] 3dip ] if ] compose
565 ] bi* compose 1 each-index-from nip swap ; inline
569 : supremum-by* ( ... seq quot: ( ... elt -- ... x ) -- ... i elt )
570 [ after? ] select-by* ; inline
572 : infimum-by* ( ... seq quot: ( ... elt -- ... x ) -- ... i elt )
573 [ before? ] select-by* ; inline
575 : ?supremum ( seq/f -- elt/f )
577 [ ] [ 2dup and [ max ] [ dupd ? ] if ] map-reduce
580 : ?infimum ( seq/f -- elt/f )
582 [ ] [ 2dup and [ min ] [ dupd ? ] if ] map-reduce
585 : change-last ( seq quot -- )
586 [ drop length 1 - ] [ change-nth ] 2bi ; inline
588 : change-last-unsafe ( seq quot -- )
589 [ drop length 1 - ] [ change-nth-unsafe ] 2bi ; inline
591 : replicate-into ( ... seq quot: ( ... -- ... newelt ) -- ... )
592 over [ length ] 2dip '[ _ dip _ set-nth-unsafe ] each-integer ; inline
594 : count* ( ... seq quot: ( ... elt -- ... ? ) -- ... % )
595 over [ count ] [ length ] bi* / ; inline
597 : find-last-index ( ... seq quot: ( ... elt i -- ... ? ) -- ... i elt )
598 [ [ 1 - ] dip find-last-integer ] (find-index) ; inline
600 : map-find-last-index ( ... seq quot: ( ... elt index -- ... result/f ) -- ... result i elt )
601 [ find-last-index ] (map-find-index) ; inline
603 :: (start-all) ( seq subseq increment -- indices )
605 [ [ subseq seq ] dip subseq-start-from dup ]
606 [ [ increment + ] keep ] produce nip ;
608 : start-all ( seq subseq -- indices )
609 dup length (start-all) ; inline
611 : start-all* ( seq subseq -- indices )
612 1 (start-all) ; inline
614 : count-subseq ( seq subseq -- n )
615 start-all length ; inline
617 : count-subseq* ( seq subseq -- n )
618 start-all* length ; inline
620 : assoc-zip-with ( quot: ( key value -- calc ) -- alist )
621 '[ _ 2keep 2array swap ] assoc-map ; inline
623 : take-while ( ... seq quot: ( ... elt -- ... ? ) -- head-slice )
624 [ '[ @ not ] find drop ] keepd swap
625 [ dup length ] unless* head-slice ; inline
627 : drop-while ( ... seq quot: ( ... elt -- ... ? ) -- tail-slice )
628 [ '[ @ not ] find drop ] keepd swap
629 [ dup length ] unless* tail-slice ; inline
631 : count-head ( seq quot -- n )
632 [ not ] compose [ find drop ] keepd length or ; inline
634 : count-tail ( seq quot -- n )
635 [ not ] compose [ find-last drop ] keepd
636 length swap [ - 1 - ] when* ; inline
638 :: interleaved-as ( seq glue exemplar -- newseq )
639 seq length dup 1 - + 0 max exemplar new-sequence :> newseq
640 seq [ 2 * newseq set-nth-unsafe ] each-index
641 seq length 1 - [ 2 * 1 + glue swap newseq set-nth-unsafe ] each-integer
644 : interleaved ( seq glue -- newseq )
645 over interleaved-as ;
647 : extract! ( ... seq quot: ( ... elt -- ... ? ) -- ... seq )
648 [ dup ] compose over [ length ] keep new-resizable
649 [ [ push-if ] 2curry reject! ] keep swap like ; inline
651 : find-pred-loop ( ... i n seq quot: ( ... elt -- ... calc ? ) -- ... calc/f i/f elt/f )
655 [ [ 3drop ] 2dip rot ]
656 [ 2drop [ 1 + ] 3dip find-pred-loop ] if
659 ] if ; inline recursive
661 : find-pred ( ... seq quot: ( ... elt -- ... calc ) pred: ( ... calc -- ... ? ) -- ... calc/f i/f elt/f )
663 [ [ length check-length ] keep ] 2dip
664 '[ nth-unsafe _ keep swap _ keep swap ] find-pred-loop swapd ; inline
666 ! https://en.wikipedia.org/wiki/Maximum_subarray_problem
667 ! Kadane's algorithm O(n) largest sum in subarray
668 : max-subarray-sum ( seq -- sum )
670 [ [ + ] keep max [ max ] keep ] each drop ;
673 { from integer read-only initial: 0 }
674 { to integer read-only initial: 0 }
676 { step integer read-only } ;
678 :: <step-slice> ( from to step seq -- step-slice )
679 step zero? [ "can't be zero" throw ] when
688 [ dup 0 < [ len + ] when 0 len clamp ] bi@
689 ! FIXME: make this work with steps
690 seq dup slice? [ collapse-slice ] when
691 step step-slice boa ;
693 M: step-slice virtual-exemplar seq>> ; inline
695 M: step-slice virtual@
696 [ step>> * ] [ from>> + ] [ seq>> ] tri ; inline
699 [ to>> ] [ from>> - ] [ step>> ] tri
700 dup 0 < [ [ neg 0 max ] dip neg ] when /mod
701 zero? [ 1 + ] unless ; inline
703 INSTANCE: step-slice virtual-sequence