calculator: use commonly defined operations

calculator/calculator/__init__.py

@@ -1,2 +1,3 @@
+import calculator.core  # isort:skip
 import calculator.ast
 import calculator.eval

calculator/calculator/core/__init__.py

@@ -0,0 +1 @@
+import calculator.core.operations

calculator/calculator/core/operations.py

@@ -0,0 +1,35 @@
+def plus(x: int, y: int) -> int:
+    return x + y
+
+
+def minus(x: int, y: int) -> int:
+    return x - y
+
+
+def times(x: int, y: int) -> int:
+    return x * y
+
+
+def int_div(x: int, y: int) -> int:
+    return x // y
+
+
+def pow(x: int, y: int) -> int:
+    return x ** y
+
+
+def identity(x: int) -> int:
+    return x
+
+
+def negate(x: int) -> int:
+    return -x
+
+
+STR_TO_BIN = {
+    "+": plus,
+    "-": minus,
+    "*": times,
+    "/": int_div,
+    "^": pow,
+}

calculator/calculator/eval/test_evaluator.py

@@ -1,5 +1,6 @@
 import pytest
 from calculator.ast import BinOp, Constant, UnaryOp
+from calculator.core import operations
 
 from .evaluator import Evaluator
 
@@ -15,20 +16,35 @@ def test_evaluate_constant(vis):
 
 
 def test_evaluate_unaryop_identity(vis):
-    op = UnaryOp(lambda x: x, Constant(42))
+    op = UnaryOp(operations.identity, Constant(42))
     assert vis.visit_and_get_value(op) == 42
 
 
 def test_evaluate_unaryop_negate(vis):
-    op = UnaryOp(lambda x: -x, Constant(-42))
+    op = UnaryOp(operations.negate, Constant(-42))
     assert vis.visit_and_get_value(op) == 42
 
 
 def test_evaluate_binop_plus(vis):
-    op = BinOp(lambda x, y: x + y, Constant(12), Constant(27))
+    op = BinOp(operations.plus, Constant(12), Constant(27))
     assert vis.visit_and_get_value(op) == 39
 
 
 def test_evaluate_binop_minus(vis):
-    op = BinOp(lambda x, y: x - y, Constant(42), Constant(51))
+    op = BinOp(operations.minus, Constant(42), Constant(51))
     assert vis.visit_and_get_value(op) == -9
+
+
+def test_evaluate_binop_times(vis):
+    op = BinOp(operations.times, Constant(6), Constant(9))
+    assert vis.visit_and_get_value(op) == 54
+
+
+def test_evaluate_binop_int_div(vis):
+    op = BinOp(operations.int_div, Constant(5), Constant(2))
+    assert vis.visit_and_get_value(op) == 2
+
+
+def test_evaluate_binop_pow(vis):
+    op = BinOp(operations.pow, Constant(3), Constant(4))
+    assert vis.visit_and_get_value(op) == 81