class TestEvaluator(unittest.TestCase):
def setUp(self):
self.evaluator = Evaluator()
def testNumericalResult(self):
self.assertEqual(self.evaluator.evaluate("2 + 5").result, 7)
self.assertEqual(self.evaluator.evaluate("3 + 5 * 2").result, 13)
self.assertEqual(self.evaluator.evaluate("8 * 7 / 2").result, 28)
self.assertEqual(self.evaluator.evaluate("8 + 6 * 2 / 3 - 1").result, 11)
self.assertEqual(self.evaluator.evaluate(" 2 + 3").result, 5)
self.assertEqual(self.evaluator.evaluate("1 / 2").result, 0.5)
self.assertEqual(self.evaluator.evaluate("2 ^ 2 * 5").result, 20)
self.assertEqual(self.evaluator.evaluate("7 * 2 ^ 3").result, 56)
self.assertEqual(self.evaluator.evaluate("7*2^3").result, 56)
self.assertEqual(self.evaluator.evaluate("8+6*2/3-1").result, 11)
self.assertEqual(self.evaluator.evaluate("-4 + 3").result, -1)
self.assertEqual(self.evaluator.evaluate("3 + -4 * 5").result, -17)
def testTreeResult(self):
tree = self.evaluator.evaluate("8 + 6 * 2 / 3 - 1").tree
self.assertEqual(tree.data, '-')
self.assertEqual(tree.right.data, 1)
self.assertEqual(tree.left.data, '+')
self.assertEqual(tree.left.left.data, 8)
self.assertEqual(tree.left.right.data, '/')
self.assertEqual(tree.left.right.right.data, 3)
self.assertEqual(tree.left.right.left.data, '*')
self.assertEqual(tree.left.right.left.left.data, 6)
self.assertEqual(tree.left.right.left.right.data, 2)
class InfixEvalUi(QtWidgets.QMainWindow):
def __init__(self, parent=None):
super().__init__(parent)
# Initialize the main window
self.main_window_ui = main_ui.Ui_MainWindow()
self.main_window_ui.setupUi(self)
# Register event handler for evaluate button
self.main_window_ui.evaluateButton.clicked.connect(self.eval_and_print)
# Initialize the error dialog
self.error_dialog = ErrorDialog()
# Initialize the graphics view
self.scene = QtWidgets.QGraphicsScene()
self.view = self.main_window_ui.treeView
self.view.setRenderHints(QtGui.QPainter.Antialiasing)
self.main_window_ui.treeView.setScene(self.scene)
self.scene.setSceneRect(0, 0, self.view.width(), self.view.height())
# Create the evaluator
self.evaluator = Evaluator()
# Evaluate the expression and output the results
def eval_and_print(self):
expression = self.main_window_ui.expressionLineEdit.text()
# Return an error if the expression is empty
if expression == '':
self.error_dialog.error_msg_label.setText(
"ERROR: Please enter an infix expression")
self.error_dialog.show()
return
# Catch some possible errors
try:
result = self.evaluator.evaluate(expression)
except ValueError as e:
self.error_dialog.error_msg_label.setText("ERROR: %s" % e)
self.error_dialog.show()
return
except IndexError:
self.error_dialog.error_msg_label.setText(
"ERROR: Expression was invalid.")
self.error_dialog.show()
return
# Clear the scene and show the results
self.scene.clear()
self.show_results(result)
def show_results(self, result):
font = QtGui.QFont("Droid Sans Mono")
font.setPointSize(20)
# Show the numerical result
result_text = QtWidgets.QGraphicsTextItem("%.3f" % result.result)
result_text.setFont(font)
result_text.setPos(-self.view.width() / 2 + 50,
-self.view.height() / 2 + 20)
self.scene.addItem(result_text)
# Show the tree
self.print_tree(result.tree, 25, -100, font, 100)
def print_tree(self, tree, x, y, font, offset):
if tree is None:
return
# Draw the tree node and the node data
result_text = QtWidgets.QGraphicsTextItem(str(tree.data))
font.setPointSize(10)
result_text.setFont(font)
result_text.setPos(x+5, y+5)
self.scene.addItem(TreeNode(x, y))
self.scene.addItem(result_text)
# Draw connection lines to child nodes
if tree.left is not None:
self._connect_to_children(x, y, offset)
if tree.right is not None:
self._connect_to_children(x, y, -offset)
# Recursively draw the left and right subtrees
self.print_tree(tree.left, x - offset, y + 60, font, offset * 0.60)
self.print_tree(tree.right, x + offset, y + 60, font, offset * 0.60)
# Draws connection lines to child nodes
def _connect_to_children(self, x, y, offset):
c1_x = x + TreeNode.radius
c1_y = y + TreeNode.radius
c2_x = c1_x - offset
c2_y = c1_y + 60
dv = center_to_circle(c1_x, c1_y, c2_x, c2_y)
self.scene.addLine(c1_x + dv.x, c1_y + dv.y,
c2_x - dv.x, c2_y - dv.y)