1 files changed, 31 insertions, 1 deletions
diff --git a/neb/std/core.py b/neb/std/core.py
index 8881468..83b164c 100644
--- a/neb/std/core.py
+++ b/neb/std/core.py
@@ -1,4 +1,4 @@
-from .. import TypeEnum, Environment, Arg, Builtin, UserFunction, evaluate, interpret, parse, lex, InterpretPanic
+from .. import TypeEnum, Environment, Arg, Builtin, UserFunction, evaluate, interpret, parse, lex, InterpretPanic, TypeWrap, Function, UserType
 from ..structs import *
 from pathlib import Path
 
@@ -182,3 +182,33 @@ def interpretEval(symbol, args, env, ns):
 
 eval_arg = Arg("arg", TypeEnum.ANY)
 CORE.register("eval", Builtin("eval", interpretEval, [eval_arg]))
+
+def interpretType(symbol, args, env, ns):
+    # (type typename parent func)
+    if not isinstance(args[0], Type):
+        raise InterpretPanic(symbol, "types must begin with a colon")
+    name = args[0].name  # NOTE: we are not evaluating the name!!
+
+    # TODO we may need to do namespace things here
+    # also, we probably shouldn't be able to rename types
+
+    if not isinstance(args[1], TypeWrap):
+        raise InterpretPanic(symbol, "parent must be a valid type", args[1])
+    elif not env.contains(args[1].name):
+        raise InterpretPanic(symbol, f"no such type {args[1]}")
+    parent = env.get(args[1].name)
+
+    func = args[2]
+    if not isinstance(func, Function):
+        raise InterpretPanic(symbol, "validation must be a :func", func)
+
+    new_type = UserType(name, parent, func)
+    env.register(name, new_type)
+    return List([])
+
+type_name_arg = Arg("name", TypeEnum.ANY, lazy=True)
+type_parent_arg = Arg("name", TypeEnum.ANY)
+type_func_arg = Arg("func", TypeEnum.ANY)
+CORE.register("type", Builtin("type", interpretType, [type_name_arg, type_parent_arg, type_func_arg]))
+
+