implement func

1 files changed, 17 insertions, 0 deletions

diff --git a/interpreter.py b/interpreter.py
index 841f5cf..f133b1f 100644
--- a/interpreter.py
+++ b/interpreter.py
@@ -318,6 +318,23 @@ def interpretBranch(expr, env):
 
 GLOBALS.register("branch", Builtin(interpretBranch))
 
+def interpretFunc(expr, env):
+    # func <name> (args) (exprs)
+    if len(expr.args) < 3:
+        raise Exception("'func' takes a name, arguments, and at least one expression")
+    if not isinstance(expr.args[0], Expr.Symbol):
+        raise Exception("'func' requires a string literal as a name")
+    name = expr.args[0].name  # NOTE: we are not evaluating the name!!
+
+    # compose a lambda
+    lambda_expr = Expr.Nary("lambda", expr.args[1:])
+    func = interpretLambda(lambda_expr, env)
+
+    env.register(name, func)
+    return None
+
+GLOBALS.register("func", Builtin(interpretFunc))
+
 def interpretEnv(expr, env_expr, env):
     ev = evaluate(env_expr, env)
     return ev  # TODO more than this?