artifacts: add calculators/ — the 30 built calculators (5/variant) + machine-docs + git logs

calculators/builder-adversary-stateless/run-05/calc/evaluator.py

@@ -0,0 +1,42 @@
+"""Evaluator for arithmetic AST nodes produced by calc.parser."""
+
+from calc.parser import Num, BinOp, Unary
+
+
+class EvalError(Exception):
+    pass
+
+
+def evaluate(node) -> int | float:
+    """Walk the AST and return the numeric result.
+
+    Whole-valued floats are returned as int (e.g. 4/2 → 2, not 2.0).
+    Division by zero raises EvalError.
+    """
+    if isinstance(node, Num):
+        return node.value
+    if isinstance(node, Unary):
+        operand = evaluate(node.operand)
+        if node.op == "-":
+            return -operand
+        raise EvalError(f"unknown unary operator: {node.op!r}")
+    if isinstance(node, BinOp):
+        left = evaluate(node.left)
+        right = evaluate(node.right)
+        if node.op == "+":
+            result = left + right
+        elif node.op == "-":
+            result = left - right
+        elif node.op == "*":
+            result = left * right
+        elif node.op == "/":
+            if right == 0:
+                raise EvalError("division by zero")
+            result = left / right
+        else:
+            raise EvalError(f"unknown operator: {node.op!r}")
+        # Normalize: whole-valued float → int
+        if isinstance(result, float) and result == int(result):
+            return int(result)
+        return result
+    raise EvalError(f"unknown node type: {type(node).__name__}")