Normalize comparison expressions, even ternary comparison expressions

[fur] / normalization.py

diff --git a/normalization.py b/normalization.py
index c48c3e9..0d967d7 100644 (file)
--- a/normalization.py
+++ b/normalization.py
@@ -9,11 +9,13 @@ NormalVariableExpression = collections.namedtuple(
     ],
 )
 
-NormalVariableAssignmentStatement = collections.namedtuple(
-    'NormalVariableAssignmentStatement',
+NormalInfixExpression = collections.namedtuple(
+    'NormalInfixExpression',
     [
-        'variable',
-        'expression',
+        'order',
+        'operator',
+        'left',
+        'right',
     ],
 )
 
@@ -25,6 +27,14 @@ NormalFunctionCallExpression = collections.namedtuple(
     ],
 )
 
+NormalVariableAssignmentStatement = collections.namedtuple(
+    'NormalVariableAssignmentStatement',
+    [
+        'variable',
+        'expression',
+    ],
+)
+
 NormalExpressionStatement = collections.namedtuple(
     'NormalExpressionStatement',
     [
@@ -73,12 +83,120 @@ def normalize_function_call_expression(counter, expression):
         ),
     )
 
+def normalize_basic_infix_operation(counter, expression):
+    counter, left_prestatements, left_expression = normalize_expression(counter, expression.left)
+    counter, right_prestatements, right_expression = normalize_expression(counter, expression.right)
+
+    left_variable = '${}'.format(counter)
+    counter += 1
+    right_variable = '${}'.format(counter)
+    counter += 1
+
+    root_prestatements = (
+        NormalVariableAssignmentStatement(
+            variable=left_variable,
+            expression=left_expression,
+        ),
+        NormalVariableAssignmentStatement(
+            variable=right_variable,
+            expression=right_expression,
+        ),
+    )
+
+    return (
+        counter,
+        left_prestatements + right_prestatements + root_prestatements,
+        NormalInfixExpression(
+            order=expression.order, # TODO Do we need this?
+            operator=expression.operator,
+            left=NormalVariableExpression(variable=left_variable),
+            right=NormalVariableExpression(variable=right_variable),
+        ),
+    )
+
+def normalize_comparison_expression(counter, expression):
+    stack = []
+
+    while isinstance(expression.left, parsing.FurInfixExpression) and expression.order == 'comparison_level':
+        stack.append((expression.operator, expression.order, expression.right))
+        expression = expression.left
+
+    counter, left_prestatements, left_expression = normalize_expression(counter, expression.left)
+    counter, right_prestatements, right_expression = normalize_expression(counter, expression.right)
+
+    left_variable = '${}'.format(counter)
+    counter += 1
+    right_variable = '${}'.format(counter)
+    counter += 1
+
+    root_prestatements = (
+        NormalVariableAssignmentStatement(
+            variable=left_variable,
+            expression=left_expression,
+        ),
+        NormalVariableAssignmentStatement(
+            variable=right_variable,
+            expression=right_expression,
+        ),
+    )
+
+    counter, result_prestatements, result_expression = (
+        counter,
+        left_prestatements + right_prestatements + root_prestatements,
+        # TODO Implement short-circuiting
+        NormalInfixExpression(
+            order=expression.order, # TODO Do we need this?
+            operator=expression.operator,
+            left=NormalVariableExpression(variable=left_variable),
+            right=NormalVariableExpression(variable=right_variable),
+        ),
+    )
+
+    while len(stack) > 0:
+        right_operator, right_order, right_expression = stack.pop()
+        and_right_expression = parsing.FurInfixExpression(
+            operator=right_operator,
+            order=right_order,
+            left=NormalVariableExpression(variable=right_variable),
+            right=right_expression,
+        )
+
+        and_expression = parsing.FurInfixExpression(
+            operator='and',
+            order='and_level',
+            left=result_expression,
+            right=and_right_expression,
+        )
+
+        counter, and_prestatements, result_expression = normalize_boolean_expression(
+            counter,
+            and_expression,
+        )
+
+        result_prestatements = result_prestatements + and_prestatements
+
+    return (counter, result_prestatements, result_expression)
+
+def normalize_boolean_expression(counter, expression):
+    # TODO Unfake this
+    return fake_normalization(counter, expression)
+
+def normalize_infix_expression(counter, expression):
+    return {
+        'multiplication_level': normalize_basic_infix_operation,
+        'addition_level': normalize_basic_infix_operation,
+        'comparison_level': normalize_comparison_expression,
+        'and_level': normalize_boolean_expression,
+        'or_level': normalize_boolean_expression,
+    }[expression.order](counter, expression)
+
 def normalize_expression(counter, expression):
     return {
         parsing.FurFunctionCallExpression: normalize_function_call_expression,
-        parsing.FurInfixExpression: fake_normalization, # TODO This should not be faked
+        parsing.FurInfixExpression: normalize_infix_expression,
         parsing.FurIntegerLiteralExpression: fake_normalization,
-        parsing.FurNegationExpression: fake_normalization,
+        parsing.FurNegationExpression: fake_normalization, # TODO Don't fake this
+        parsing.FurParenthesizedExpression: fake_normalization, # TODO Don't fake this
         parsing.FurStringLiteralExpression: fake_normalization,
         parsing.FurSymbolExpression: fake_normalization,
     }[type(expression)](counter, expression)