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

calculators/builder-adversary-deferred/run-01/calc/evaluator.py

@@ -0,0 +1,43 @@
+from __future__ import annotations
+from calc.parser import Num, BinOp, Unary, Node
+
+
+class EvalError(Exception):
+    pass
+
+
+def evaluate(node: Node) -> int | float:
+    """Walk the AST and return the numeric result."""
+    if isinstance(node, Num):
+        return node.value
+    if isinstance(node, Unary):
+        val = evaluate(node.operand)
+        if node.op == '-':
+            return -val
+        raise EvalError(f"unknown unary operator: {node.op!r}")
+    if isinstance(node, BinOp):
+        left = evaluate(node.left)
+        right = evaluate(node.right)
+        if node.op == '+':
+            return left + right
+        if node.op == '-':
+            return left - right
+        if node.op == '*':
+            return left * right
+        if node.op == '/':
+            if right == 0:
+                raise EvalError("division by zero")
+            return left / right
+        raise EvalError(f"unknown binary operator: {node.op!r}")
+    raise EvalError(f"unknown node type: {type(node)!r}")
+
+
+def fmt_result(v: int | float) -> str:
+    """Format a result for display.
+
+    Rule: whole-valued floats (e.g. 2.0 from 4/2) print without a trailing .0;
+    non-whole floats print normally; integers print as integers.
+    """
+    if isinstance(v, float) and v.is_integer():
+        return str(int(v))
+    return str(v)