diff options
Diffstat (limited to 'neb')
| -rw-r--r-- | neb/std/core.py | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/neb/std/core.py b/neb/std/core.py index 50a0c3e..9a9e56d 100644 --- a/neb/std/core.py +++ b/neb/std/core.py @@ -98,6 +98,46 @@ def interpretForEach(symbol, args, env, ns): for_each_arg = Arg("list", TypeEnum.LIST) CORE.register("for-each", NebSyntax("for-each", interpretForEach, [for_each_arg, for_body_arg], for_body_arg)) +def interpretTakeWhile(symbol, args, env, ns): + coll = evaluate(args[0], env, ns) + if not isinstance(coll, List): + raise InterpretPanic(symbol, "coll must be a :list", coll) + new_env = Environment(env) + ret = [] + ev = None + for item in coll.args: + new_env.register("_item_", evaluate(item, env, ns)) + for arg in args[1:]: + ev = evaluate(arg, new_env, ns) + if not isinstance(ev, Bool): + raise InterpretPanic(symbol, "condition must evaluate to a :bool", ev) + if ev.value is False: + break + ret.append(item) + return List(ret) + +CORE.register("take-while", NebSyntax("take-while", interpretTakeWhile, [for_each_arg, for_body_arg], for_body_arg)) + +def interpretDropWhile(symbol, args, env, ns): + coll = evaluate(args[0], env, ns) + if not isinstance(coll, List): + raise InterpretPanic(symbol, "coll must be a :list", coll) + new_env = Environment(env) + ev = None + which_idx = None + for idx, item in enumerate(coll.args): + which_idx = idx + new_env.register("_item_", evaluate(item, env, ns)) + for arg in args[1:]: + ev = evaluate(arg, new_env, ns) + if not isinstance(ev, Bool): + raise InterpretPanic(symbol, "condition must evaluate to a :bool", ev) + if ev.value is False: + break + return List(coll.args[which_idx:]) + +CORE.register("drop-while", NebSyntax("drop-while", interpretDropWhile, [for_each_arg, for_body_arg], for_body_arg)) + def interpretBranch(symbol, args, env, ns): for arg in args: if len(arg.args) != 2: |