sequences.extras: adding subseq-indices word

mrjbq7 · Nov 12, 2024 · ae50ca8 · ae50ca8
1 parent 9193f64
commit ae50ca8
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diff --git a/extra/sequences/extras/extras-tests.factor b/extra/sequences/extras/extras-tests.factor
@@ -261,6 +261,10 @@ strings tools.test ;
 { "cdef" } [ 2 f "abcdef" subseq* ] unit-test
 { "cd" } [ -4 -2 "abcdef" subseq* ] unit-test
 
+{ { } } [ "abcabc" "abcd" subseq-indices ] unit-test
+{ { 0 3 } } [ "abcabc" "abc" subseq-indices ] unit-test
+{ { 0 3 } } [ "abcabcabc" "abcabc" subseq-indices ] unit-test
+
 { "foo" "" } [ "foo" [ ascii:blank? ] cut-when ] unit-test
 { "foo" " " } [ "foo " [ ascii:blank? ] cut-when ] unit-test
 { "" " foo" } [ " foo" [ ascii:blank? ] cut-when ] unit-test

diff --git a/extra/sequences/extras/extras.factor b/extra/sequences/extras/extras.factor
@@ -24,6 +24,11 @@ IN: sequences.extras
         dup _ (a..b] [ rot [ subseq _ call ] keep ] with each
     ] each drop ; inline
 
+: subseq-indices ( seq subseq -- indices )
+    [ 0 ] 2dip '[
+        _ _ subseq-index-from [ [ 1 + ] keep ] [ f f ] if* dup
+    ] [ ] produce 2nip ;
+
 : map-like ( seq exemplar -- seq' )
     '[ _ like ] map ; inline