diff options
Diffstat (limited to 'VM.hs')
| -rw-r--r-- | VM.hs | 5 |
1 files changed, 3 insertions, 2 deletions
@@ -152,8 +152,9 @@ vmRunBuiltin state "sys-stdin" [] = return (RVNum (-1), state) vmRunBuiltin state "sys-stdout" [] = return (RVNum (-2), state) vmRunBuiltin state "sys-stderr" [] = return (RVNum (-3), state) vmRunBuiltin state "length" [RVString str] = return (RVNum (length str), state) -vmRunBuiltin state "substr" [RVString str, RVNum idx, RVNum len] = - return (RVString (take len (drop idx str)), state) +vmRunBuiltin state "substr" [RVNum idx, RVNum len, RVString str] = + let s = (if len >= 0 then take len else id) (drop idx str) + in return (RVString s, state) vmRunBuiltin state "ord" [RVString str] = return (RVNum (case str of { "" -> 0; c:_ -> ord c }), state) vmRunBuiltin state "chr" [RVNum num] = return (RVString [chr num], state) vmRunBuiltin state "concat" values |