refactor: only evaluate expressions as needed

1 files changed, 20 insertions, 13 deletions

diff --git a/runner.py b/runner.py
index 1023473..7de2666 100644
--- a/runner.py
+++ b/runner.py
@@ -7,6 +7,25 @@ def peek(inp):
         return None
     return inp[0]
 
+def evaluate_expression(expr):
+    if not expr.symbol.name in STD:
+        raise Exception(f"no such symbol: {expr.symbol.name}")
+    this_func = STD[expr.symbol.name]
+
+    # try to match the signature
+    in_sig = expr.in_sig()
+    if in_sig in this_func:
+        ret = this_func[expr.in_sig()].impl(*(expr.args))
+        return ret
+
+    # evaluate inner expressions, if possible/necessary
+    for idx, arg in enumerate(expr.args):
+        if arg.type_ == NebType.EXPR:
+            expr.args[idx] = evaluate_expression(arg)
+            return evaluate_expression(expr)
+
+    raise Exception(f"'{expr.symbol.name}' called with unknown signature: '{expr.in_sig()}'")
+
 def evaluate(items, pop):
     nxt = peek(items)
     if nxt is None:
@@ -19,19 +38,7 @@ def evaluate(items, pop):
         this_func = STD[nxt.name]
         return evaluate(items[1:], this_func[list(this_func.keys())[0]].impl) # TODO show all
     elif isinstance(nxt, NebExpression):
-        if not nxt.symbol.name in STD:
-            raise Exception(f"no such symbol: {nxt.symbol.name}")
-        this_func = STD[nxt.symbol.name]
-
-        # evaluate inner expressions
-        for idx, arg in enumerate(nxt.args):
-            if isinstance(arg, NebExpression):
-                nxt.args[idx] = evaluate([arg], pop)
-
-        if nxt.maybe_sig() not in this_func:
-            raise Exception(f"'{nxt.symbol.name}' called with unknown signature: '{nxt.maybe_sig()}'")
-        ret = this_func[nxt.maybe_sig()].impl(*(nxt.args))
-        return evaluate(items[1:], ret)
+        return evaluate(items[1:], evaluate_expression(nxt))
     else:
         raise Exception("expected a literal or an expression")