exponentiation as builtin

lib.py

@@ -83,6 +83,8 @@ def execute(program):
                 return reduce(lambda a, b: (a[0], a[1]*b[1]), subs[1:])
             elif ctx[0] == _ident("/"):
                 return reduce(lambda a, b: (a[0], a[1]/b[1]), subs[1:])
+            elif ctx[0] == _ident("^"):
+                return reduce(lambda a, b: (a[0], a[1]**b[1]), subs[1:])
             elif ctx[0] == _ident("=="):
                 return ("number", 1.0 if subs[1] == subs[2] else 0.0)
             elif ctx[0] == _ident("="):