diff options
Diffstat (limited to 'src/boot/utility.boot')
| -rw-r--r-- | src/boot/utility.boot | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/src/boot/utility.boot b/src/boot/utility.boot index 78e01a97..0ce3362a 100644 --- a/src/boot/utility.boot +++ b/src/boot/utility.boot @@ -33,7 +33,9 @@ import initial_-env namespace BOOTTRAN module utility (objectMember?, symbolMember?, stringMember?, - charMember?, scalarMember?, listMember?) + charMember?, scalarMember?, listMember?, reverse!) + +--% membership operators objectMember?(x,l) == cons? l => sameObject?(x,first l) or objectMember?(x,rest l) @@ -78,3 +80,16 @@ listMember?(x,l) == listEq?(x,first l) => return true l := rest l return listEq?(x,l) + +--% list reversal + +reverse! l == + l1 := nil + repeat + cons? l => + l2 := rest l + l.rest := l1 + l1 := l + l := l2 + return l1 + |