1 ! Copyright (C) 2009 Joe Groff.
2 ! See https://factorcode.org/license.txt for BSD license.
3 USING: accessors arrays assocs kernel locals math sequences
7 TUPLE: product-sequence { sequences array read-only } { lengths array read-only } ;
9 : <product-sequence> ( sequences -- product-sequence )
10 >array dup [ length ] map product-sequence boa ;
12 INSTANCE: product-sequence sequence
14 M: product-sequence length lengths>> product ;
18 : ns ( n lengths -- ns )
21 : nths ( ns seqs -- nths )
24 : product@ ( n product-sequence -- ns seqs )
25 [ lengths>> ns ] [ nip sequences>> ] 2bi ;
27 :: (carry-n) ( ns lengths i -- )
29 i ns nth-unsafe i lengths nth-unsafe = [
31 i 1 + ns [ 1 + ] change-nth-unsafe
32 ns lengths i 1 + (carry-n)
34 ] unless ; inline recursive
36 : carry-ns ( ns lengths -- )
39 : product-iter ( ns lengths -- )
40 [ 0 over [ 1 + ] change-nth-unsafe ] dip carry-ns ; inline
42 : start-product-iter ( sequences -- ns lengths )
43 [ length 0 <array> ] [ [ length ] map ] bi ; inline
45 : end-product-iter? ( ns lengths -- ? )
46 [ last-unsafe ] same? ; inline
48 : product-length ( sequences -- length )
49 [ length ] [ * ] map-reduce ; inline
53 M: product-sequence nth
56 :: product-each ( ... sequences quot: ( ... seq -- ... ) -- ... )
57 sequences start-product-iter :> ( ns lengths )
58 lengths [ 0 = ] any? [
59 [ ns lengths end-product-iter? ]
60 [ ns sequences nths quot call ns lengths product-iter ] until
63 :: product-map-as ( ... sequences quot: ( ... seq -- ... value ) exemplar -- ... sequence )
65 sequences product-length exemplar
67 sequences [ quot call i result set-nth-unsafe i 1 + i! ] product-each
71 : product-map ( ... sequences quot: ( ... seq -- ... value ) -- ... sequence )
72 over product-map-as ; inline
74 :: product-map>assoc ( ... sequences quot: ( ... seq -- ... key value ) exemplar -- ... assoc )
76 sequences product-length { }
78 sequences [ quot call 2array i result set-nth-unsafe i 1 + i! ] product-each
80 ] new-like exemplar assoc-like ; inline
82 :: product-find ( ... sequences quot: ( ... seq -- ... ? ) -- ... sequence )
83 sequences start-product-iter :> ( ns lengths )
84 lengths [ 0 = ] any? [ f ] [
85 f [ ns lengths end-product-iter? over or ]
86 [ drop ns sequences nths quot keep and ns lengths product-iter ] until