diff options
Diffstat (limited to 'python/core.py')
| -rw-r--r-- | python/core.py | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/python/core.py b/python/core.py index d10047d..4a64594 100644 --- a/python/core.py +++ b/python/core.py @@ -60,7 +60,9 @@ def cons(x, seq): return List([x]) + List(seq) def concat(*lsts): return List(chain(*lsts)) -def nth(lst, idx): return lst[idx] +def nth(lst, idx): + if idx < len(lst): return lst[idx] + else: throw("nth: index out of range") def first(lst): return lst[0] @@ -68,7 +70,9 @@ def rest(lst): return List(lst[1:]) def empty_Q(lst): return len(lst) == 0 -def count(lst): return len(lst) +def count(lst): + if types._nil_Q(lst): return 0 + else: return len(lst) # retains metadata def conj(lst, *args): @@ -114,6 +118,8 @@ ns = { 'false?': types._false_Q, 'symbol': types._symbol, 'symbol?': types._symbol_Q, + 'keyword': types._keyword, + 'keyword?': types._keyword_Q, 'pr-str': pr_str, 'str': do_str, |