Prevent assignment to a builtin variable

[fur] / normalization.py

diff --git a/normalization.py b/normalization.py
index 94d3a7c..a5863a1 100644 (file)
--- a/normalization.py
+++ b/normalization.py
@@ -1,6 +1,7 @@
 import collections
 
 import parsing
+import util
 
 NormalVariableExpression = collections.namedtuple(
     'NormalVariableExpression',
@@ -9,6 +10,13 @@ NormalVariableExpression = collections.namedtuple(
     ],
 )
 
+NormalNegationExpression = collections.namedtuple(
+    'NormalNegationExpression',
+    [
+        'internal_expression',
+    ],
+)
+
 NormalInfixExpression = collections.namedtuple(
     'NormalInfixExpression',
     [
@@ -23,7 +31,16 @@ NormalFunctionCallExpression = collections.namedtuple(
     'NormalFunctionCallExpression',
     [
         'function',
-        'arguments',
+        'argument_count',
+        'argument_items',
+    ],
+)
+
+NormalArrayVariableInitializationStatement = collections.namedtuple(
+    'NormalArrayVariableInitializationStatement',
+    [
+        'variable',
+        'items',
     ],
 )
 
@@ -35,6 +52,14 @@ NormalVariableInitializationStatement = collections.namedtuple(
     ],
 )
 
+NormalVariableReassignmentStatement = collections.namedtuple(
+    'NormalVariableReassignmentStatement',
+    [
+        'variable',
+        'expression',
+    ],
+)
+
 NormalExpressionStatement = collections.namedtuple(
     'NormalExpressionStatement',
     [
@@ -42,6 +67,32 @@ NormalExpressionStatement = collections.namedtuple(
     ],
 )
 
+NormalAssignmentStatement = collections.namedtuple(
+    'NormalAssignmentStatement',
+    [
+        'target',
+        'expression',
+    ],
+)
+
+NormalIfElseStatement = collections.namedtuple(
+    'NormalIfElseStatement',
+    [
+        'condition_expression',
+        'if_statements',
+        'else_statements',
+    ],
+)
+
+NormalFunctionDefinitionStatement = collections.namedtuple(
+    'NormalFunctionDefinitionStatement',
+    [
+        'name',
+        'argument_name_list',
+        'statement_list',
+    ],
+)
+
 NormalProgram = collections.namedtuple(
     'NormalProgram',
     [
@@ -49,6 +100,7 @@ NormalProgram = collections.namedtuple(
     ],
 )
 
+# TODO Get rid of this
 def fake_normalization(counter, thing):
     return (counter, (), thing)
 
@@ -74,12 +126,29 @@ def normalize_function_call_expression(counter, expression):
         ))
         counter += 1
 
+    arguments_variable = '${}'.format(counter)
+    counter += 1
+
+    prestatements.append(NormalArrayVariableInitializationStatement(
+        variable=arguments_variable,
+        items=tuple(arguments),
+    ))
+
+    counter, function_prestatements, function_expression = normalize_expression(
+        counter,
+        expression.function,
+    )
+
+    for ps in function_prestatements:
+        prestatements.append(ps)
+
     return (
         counter,
         tuple(prestatements),
         NormalFunctionCallExpression(
-            expression.function, # TODO Normalize the function
-            arguments=tuple(arguments),
+            function=function_expression,
+            argument_count=len(arguments),
+            argument_items=NormalVariableExpression(variable=arguments_variable),
         ),
     )
 
@@ -178,8 +247,39 @@ def normalize_comparison_expression(counter, expression):
     return (counter, result_prestatements, result_expression)
 
 def normalize_boolean_expression(counter, expression):
-    # TODO Unfake this
-    return fake_normalization(counter, expression)
+    counter, left_prestatements, left_expression = normalize_expression(counter, expression.left)
+    counter, right_prestatements, right_expression = normalize_expression(counter, expression.right)
+
+    result_variable = '${}'.format(counter)
+    if_else_prestatment = NormalVariableInitializationStatement(variable=result_variable, expression=left_expression)
+    counter += 1
+
+    condition_expression=NormalVariableExpression(variable=result_variable)
+    short_circuited_statements = right_prestatements + (NormalVariableReassignmentStatement(variable=result_variable, expression=right_expression),)
+
+    if expression.operator == 'and':
+        if_else_statement = NormalIfElseStatement(
+            condition_expression=condition_expression,
+            if_statements=short_circuited_statements,
+            else_statements=(),
+        )
+
+    elif expression.operator == 'or':
+        if_else_statement = NormalIfElseStatement(
+            condition_expression=condition_expression,
+            if_statements=(),
+            else_statements=short_circuited_statements,
+        )
+
+    else:
+        raise Exception('Unable to handle operator "{}"'.format(expression.operator))
+
+    return (
+        counter,
+        left_prestatements + (if_else_prestatment, if_else_statement),
+        NormalVariableExpression(variable=result_variable),
+    )
+
 
 def normalize_infix_expression(counter, expression):
     return {
@@ -190,20 +290,37 @@ def normalize_infix_expression(counter, expression):
         'or_level': normalize_boolean_expression,
     }[expression.order](counter, expression)
 
+def normalize_negation_expression(counter, expression):
+    counter, prestatements, internal_expression = normalize_expression(counter, expression.value)
+
+    internal_variable = '${}'.format(counter)
+    counter += 1
+
+    return (
+        counter,
+        prestatements + (NormalVariableInitializationStatement(variable=internal_variable, expression=internal_expression),),
+        NormalNegationExpression(internal_expression=NormalVariableExpression(variable=internal_variable)),
+    )
+
 def normalize_expression(counter, expression):
     return {
+        NormalInfixExpression: fake_normalization,
+        NormalVariableExpression: fake_normalization,
         parsing.FurFunctionCallExpression: normalize_function_call_expression,
         parsing.FurInfixExpression: normalize_infix_expression,
         parsing.FurIntegerLiteralExpression: fake_normalization,
-        parsing.FurNegationExpression: fake_normalization, # TODO Don't fake this
-        parsing.FurParenthesizedExpression: fake_normalization, # TODO Don't fake this
+        parsing.FurNegationExpression: normalize_negation_expression,
         parsing.FurStringLiteralExpression: fake_normalization,
         parsing.FurSymbolExpression: fake_normalization,
     }[type(expression)](counter, expression)
 
 def normalize_expression_statement(counter, statement):
+    # TODO Verify all expression types are supported and just call normalize_expression
     counter, prestatements, normalized = {
         parsing.FurFunctionCallExpression: normalize_function_call_expression,
+        parsing.FurSymbolExpression: normalize_expression,
+        parsing.FurInfixExpression: normalize_expression,
+        parsing.FurIntegerLiteralExpression: normalize_expression,
     }[type(statement.expression)](counter, statement.expression)
 
     return (
@@ -212,22 +329,47 @@ def normalize_expression_statement(counter, statement):
         NormalExpressionStatement(expression=normalized),
     )
 
+def normalize_function_definition_statement(counter, statement):
+    return (
+        counter,
+        (),
+        NormalFunctionDefinitionStatement(
+            name=statement.name,
+            argument_name_list=statement.argument_name_list,
+            statement_list=normalize_statement_list(statement.statement_list),
+        ),
+    )
+
+def normalize_assignment_statement(counter, statement):
+    counter, prestatements, normalized_expression = normalize_expression(counter, statement.expression)
+    return (
+        counter,
+        prestatements,
+        NormalAssignmentStatement(
+            target=statement.target,
+            expression=normalized_expression,
+        ),
+    )
+
 def normalize_statement(counter, statement):
     return {
+        parsing.FurAssignmentStatement: normalize_assignment_statement,
         parsing.FurExpressionStatement: normalize_expression_statement,
-        parsing.FurAssignmentStatement: fake_normalization,
+        parsing.FurFunctionDefinitionStatement: normalize_function_definition_statement,
     }[type(statement)](counter, statement)
 
-def normalize(program):
+@util.force_generator(tuple)
+def normalize_statement_list(statement_list):
     counter = 0
-    statement_list = []
 
-    for statement in program.statement_list:
+    for statement in statement_list:
         counter, prestatements, normalized = normalize_statement(counter, statement)
         for s in prestatements:
-            statement_list.append(s)
-        statement_list.append(normalized)
+            yield s
+        yield normalized
+
+def normalize(program):
 
     return NormalProgram(
-        statement_list=statement_list,
+        statement_list=normalize_statement_list(program.statement_list),
     )