Merge pull request #79 from realpython/emacs-the-best-python-editor

Adding code to support Emacs article

Author: JFincher42

emacs-the-best-python-editor/PyEval/Pipfile

@@ -0,0 +1,14 @@
+[[source]]
+url = "https://pypi.org/simple"
+verify_ssl = true
+name = "pypi"
+
+[packages]
+
+[dev-packages]
+autopep8 = "*"
+black = "*"
+jedi = "*"
+
+[requires]
+python_version = "3.6"

emacs-the-best-python-editor/PyEval/Pipfile.lock

@@ -0,0 +1,9 @@
+"""
+Example code for debugging PyEval
+"""
+
+from pyeval_expression import Expression
+
+expr = Expression("53 * -2 + 4")
+expr.parse()
+print(expr.result())

emacs-the-best-python-editor/PyEval/debug-example.py

@@ -0,0 +1,137 @@
+"""
+Test cases for PyEval
+
+Jon Fincher, July 2018
+"""
+import unittest
+from pyeval_expression import Expression
+
+
+class TestPyEval(unittest.TestCase):
+
+    """
+    Validation of Expression and Operator classes.
+    No setup function is needed
+    """
+
+    def test_positive_operand_expression(self):
+        """
+        Tests a single positive operand expression
+        """
+        expr = Expression("53")
+        self.assertEqual("53 ", expr.result(), "ERROR: Positive operand")
+
+    def test_negative_operand_expression(self):
+        """
+        Tests a single negative operand expression
+        """
+        expr = Expression("-53")
+        self.assertEqual("-53 ", expr.result(), "ERROR: Negative operand")
+
+    def test_double_term_expression(self):
+        """
+        Tests a set of double term expressions
+        """
+        expr = Expression("53+2")
+        self.assertEqual(
+            "53 2 + ", expr.result(), "ERROR: Double positive term expression"
+        )
+        expr = Expression("-53+2")
+        self.assertEqual(
+            "-53 2 + ",
+            expr.result(),
+            "ERROR: Negative/positive term expression",
+        )
+        expr = Expression("53+-2")
+        self.assertEqual(
+            "53 -2 + ",
+            expr.result(),
+            "ERROR: Positive/negative term expression",
+        )
+        expr = Expression("-53+-2")
+        self.assertEqual(
+            "-53 -2 + ",
+            expr.result(),
+            "ERROR: Double negative term expression",
+        )
+
+    def test_double_term_operands(self):
+        """
+        Tests a set of operands
+        """
+        expr = Expression("53+2")
+        self.assertEqual(
+            "53 2 + ", expr.result(), "ERROR: Additive expression"
+        )
+        expr = Expression("53-2")
+        self.assertEqual(
+            "53 2 - ", expr.result(), "ERROR: Subtrative expression"
+        )
+        expr = Expression("53*2")
+        self.assertEqual(
+            "53 2 * ", expr.result(), "ERROR: Multiplicative expression"
+        )
+        expr = Expression("53/2")
+        self.assertEqual("53 2 / ", expr.result(), "ERROR: Divide expression")
+
+    def test_triple_term_expression(self):
+        """
+        Tests a set of triple term expressions
+        """
+        expr = Expression("53+2+37")
+        self.assertEqual(
+            "53 2 37 + + ", expr.result(), "ERROR: Add/Add expression"
+        )
+        expr = Expression("53+2*37")
+        self.assertEqual(
+            "53 2 37 * + ", expr.result(), "ERROR: Add/Multiply expression"
+        )
+        expr = Expression("53*2+37")
+        self.assertEqual(
+            "53 2 * 37 + ", expr.result(), "ERROR: Multiply/Add expression"
+        )
+        expr = Expression("53*2*37")
+        self.assertEqual(
+            "53 2 37 * * ",
+            expr.result(),
+            "ERROR: Multiply/Multiply expression",
+        )
+
+    def test_whitespace_expression(self):
+        """
+        Tests a set of expressions with a variety of whitespace
+        """
+        expr = Expression("53+2+37")
+        self.assertEqual(
+            "53 2 37 + + ", expr.result(), "ERROR: No whitespace expression"
+        )
+        expr = Expression("53 + 2 + 37")
+        self.assertEqual(
+            "53 2 37 + + ",
+            expr.result(),
+            "ERROR: Infixed whitespace expression",
+        )
+        expr = Expression(" 53+2+37 ")
+        self.assertEqual(
+            "53 2 37 + + ",
+            expr.result(),
+            "ERROR: Pre/post-fixed whitespace expression",
+        )
+        expr = Expression(" 53 + 2 + 37 ")
+        self.assertEqual(
+            "53 2 37 + + ",
+            expr.result(),
+            "ERROR: Pre/post/in-fixed whitespace expression",
+        )
+        expr = Expression("  53  +  2  +  37  ")
+        self.assertEqual(
+            "53 2 37 + + ",
+            expr.result(),
+            "ERROR: Multiple whitespace expression",
+        )
+
+        # This test should throw an exception - spaces in between operands
+        # should give an error
+        with self.assertRaises(SyntaxError):
+            expr = Expression("  53  +  -  2  +  37  ")
+            expr.parse()