sequences.extras: adding reverse-as.

2012-09-19 13:29:34 -07:00 · 2012-09-19 13:29:34 -07:00 · 346e1f4cf8
parent e97c8971a5
commit 346e1f4cf8
2 changed files with 13 additions and 0 deletions
--- a/extra/sequences/extras/extras-tests.factor
+++ b/extra/sequences/extras/extras-tests.factor
@ -146,3 +146,6 @@ IN: sequences.extras.tests
 { V{ 97 115 100 102 } } [
    "asdf" [ [ read1 ] V{ } loop>sequence ] with-string-reader
 ] unit-test
+
+{ "" } [ { } "" reverse-as ] unit-test
+{ "ABC" } [ { 67 66 65 } "" reverse-as ] unit-test
--- a/extra/sequences/extras/extras.factor
+++ b/extra/sequences/extras/extras.factor
@ -315,3 +315,13 @@ INSTANCE: odds immutable-sequence

 : loop>array ( quot -- seq )
   { } loop>sequence ; inline
+
+<PRIVATE
+
+: (reverse) ( seq -- newseq )
+    dup [ length ] keep new-sequence [ 0 swap copy ] keep reverse! ;
+
+PRIVATE>
+
+: reverse-as ( seq exemplar -- newseq )
+    [ (reverse) ] [ like ] bi* ;