Added if expression statements
[fur] / transformation.py
index c3ced00..0b58907 100644 (file)
@@ -1,7 +1,7 @@
 import collections
 
 import normalization
-import parsing
+import parsing # TODO Remove this import, as we should be normalizing everything before it gets here
 
 CIntegerLiteral = collections.namedtuple(
     'CIntegerLiteral',
@@ -18,13 +18,6 @@ CStringLiteral = collections.namedtuple(
     ],
 )
 
-CConstantExpression = collections.namedtuple(
-    'CConstantExpression',
-    [
-        'value'
-    ],
-)
-
 CVariableExpression = collections.namedtuple(
     'CVariableExpression',
     [
@@ -59,11 +52,13 @@ CFunctionCallForFurInfixOperator = collections.namedtuple(
 CFunctionCallExpression = collections.namedtuple(
     'CFunctionCallExpression',
     [
-        'name',
-        'arguments',
+        'function_expression',
+        'argument_count',
+        'argument_items',
     ],
 )
 
+# TODO We are currently not changing variables, just preventing them from being accessed.
 CSymbolAssignmentStatement = collections.namedtuple(
     'CSymbolAssignmentStatement',
     [
@@ -73,8 +68,24 @@ CSymbolAssignmentStatement = collections.namedtuple(
     ],
 )
 
-CVariableAssignmentStatement = collections.namedtuple(
-    'CVariableAssignmentStatement',
+CArrayVariableInitializationStatement = collections.namedtuple(
+    'CArrayVariableInitializationStatement',
+    [
+        'variable',
+        'items',
+    ],
+)
+
+CVariableInitializationStatement = collections.namedtuple(
+    'CVariableInitializationStatement',
+    [
+        'variable',
+        'expression',
+    ],
+)
+
+CVariableReassignmentStatement = collections.namedtuple(
+    'CVariableReassignmentStatement',
     [
         'variable',
         'expression',
@@ -88,10 +99,39 @@ CExpressionStatement = collections.namedtuple(
     ],
 )
 
+CIfElseStatement = collections.namedtuple(
+    'CIfElseStatement',
+    [
+        'condition_expression',
+        'if_statement_list',
+        'else_statement_list',
+    ],
+)
+
+CFunctionDeclaration = collections.namedtuple(
+    'CFunctionDeclaration',
+    [
+        'name',
+    ],
+)
+
+# TODO If a function definition doesn't end with an expression, we have issues currently because we try to return statement.
+# TODO Closures currently wrap entire defining environment, even symbols that are not used, which makes garbage collection ineffective.
+CFunctionDefinition = collections.namedtuple(
+    'CFunctionDefinition',
+    [
+        'name',
+        'argument_name_list',
+        'statement_list',
+    ],
+)
+
 CProgram = collections.namedtuple(
     'CProgram',
     [
         'builtin_set',
+        'function_definition_list',
+        'operator_declarations',
         'statements',
         'standard_libraries',
         'string_literal_list',
@@ -99,19 +139,74 @@ CProgram = collections.namedtuple(
     ],
 )
 
-EQUALITY_LEVEL_OPERATOR_TO_FUNCTION_NAME_MAPPING = {
-    '==':   'equals',
-    '!=':   'notEquals',
-    '<=':   'lessThanOrEqual',
-    '>=':   'greaterThanOrEqual',
-    '<':    'lessThan',
-    '>':    'greaterThan',
+BUILTINS = {
+    'false':    [],
+    'pow':      ['math.h'],
+    'print':    ['stdio.h'],
+    'true':     [],
+}
+
+def transform_variable_expression(accumulators, expression):
+    return CVariableExpression(variable=expression.variable)
+
+def transform_string_literal_expression(accumulators, expression):
+    value = expression.string
+
+    try:
+        index = accumulators.string_literal_list.index(value)
+    except ValueError:
+        index = len(accumulators.string_literal_list)
+        accumulators.string_literal_list.append(value)
+
+    return CStringLiteral(index=index, value=value)
+
+def transform_symbol_expression(accumulators, expression):
+    if expression.symbol in BUILTINS:
+        accumulators.builtin_set.add(expression.symbol)
+
+    try:
+        symbol_list_index = accumulators.symbol_list.index(expression.symbol)
+    except ValueError:
+        symbol_list_index = len(accumulators.symbol_list)
+        accumulators.symbol_list.append(expression.symbol)
+
+    return CSymbolExpression(
+        symbol=expression.symbol,
+        symbol_list_index=symbol_list_index,
+    )
+
+CInfixDeclaration = collections.namedtuple(
+    'CInfixDeclaration',
+    [
+        'name',
+        'in_type',
+        'out_type',
+        'operator',
+    ],
+)
+
+INFIX_OPERATOR_TO_DECLARATION = {
+    '+':    CInfixDeclaration(name='add', in_type='integer', out_type='integer', operator='+'),
+    '-':    CInfixDeclaration(name='subtract', in_type='integer', out_type='integer', operator='-'),
+    '*':    CInfixDeclaration(name='multiply', in_type='integer', out_type='integer', operator='*'),
+    '//':   CInfixDeclaration(name='integerDivide', in_type='integer', out_type='integer', operator='/'),
+    '%':    CInfixDeclaration(name='modularDivide', in_type='integer', out_type='integer', operator='%'),
+    'and':  CInfixDeclaration(name='and', in_type='boolean', out_type='boolean', operator='&&'),
+    'or':   CInfixDeclaration(name='or', in_type='boolean', out_type='boolean', operator='||'),
+    '==':   CInfixDeclaration(name='equals', in_type='integer', out_type='boolean', operator='=='),
+    '!=':   CInfixDeclaration(name='notEquals', in_type='integer', out_type='boolean', operator='!='),
+    '<=':   CInfixDeclaration(name='lessThanOrEqual', in_type='integer', out_type='boolean', operator='<='),
+    '>=':   CInfixDeclaration(name='greaterThanOrEqual', in_type='integer', out_type='boolean', operator='>='),
+    '<':    CInfixDeclaration(name='lessThan', in_type='integer', out_type='boolean', operator='<'),
+    '>':    CInfixDeclaration(name='greaterThan', in_type='integer', out_type='boolean', operator='>'),
 }
 
-def transform_equality_level_expression(accumulators, expression):
+def transform_comparison_level_expression(accumulators, expression):
+    accumulators.operator_set.add(INFIX_OPERATOR_TO_DECLARATION[expression.operator])
+
     # Transform expressions like 1 < 2 < 3 into expressions like 1 < 2 && 2 < 3
-    if isinstance(expression.left, parsing.FurInfixExpression) and expression.left.order == 'equality_level':
-        left = transform_equality_level_expression(
+    if isinstance(expression.left, parsing.FurInfixExpression) and expression.left.order == 'comparison_level':
+        left = transform_comparison_level_expression(
             accumulators,
             expression.left
         )
@@ -128,150 +223,133 @@ def transform_equality_level_expression(accumulators, expression):
             name='and',
             left=left,
             right=CFunctionCallForFurInfixOperator(
-                name=EQUALITY_LEVEL_OPERATOR_TO_FUNCTION_NAME_MAPPING[expression.operator],
+                name=INFIX_OPERATOR_TO_DECLARATION[expression.operator].name,
                 left=middle,
                 right=right,
             ),
         )
 
     return CFunctionCallForFurInfixOperator(
-        name=EQUALITY_LEVEL_OPERATOR_TO_FUNCTION_NAME_MAPPING[expression.operator],
+        name=INFIX_OPERATOR_TO_DECLARATION[expression.operator].name,
         left=transform_expression(accumulators, expression.left),
         right=transform_expression(accumulators, expression.right),
     )
 
-BUILTINS = {
-    'false':    [],
-    'pow':      ['math.h'],
-    'print':    ['stdio.h'],
-    'true':     [],
-}
-
-def transform_variable_expression(accumulators, expression):
-    return CVariableExpression(variable=expression.variable)
-
-def transform_expression(accumulators, expression):
-    if isinstance(expression, parsing.FurParenthesizedExpression):
-        # Parentheses can be removed because everything in the C output is explicitly parenthesized
-        return transform_expression(accumulators, expression.internal)
-
-    if isinstance(expression, parsing.FurNegationExpression):
-        return transform_negation_expression(accumulators, expression)
-
-    if isinstance(expression, parsing.FurFunctionCallExpression):
-        return transform_function_call_expression(accumulators, expression)
+def transform_infix_expression(accumulators, expression):
+    if expression.order == 'comparison_level':
+        return transform_comparison_level_expression(accumulators, expression)
 
-    if isinstance(expression, parsing.FurSymbolExpression):
-        if expression.value in ['true', 'false']:
-            return CConstantExpression(value=expression.value)
+    accumulators.operator_set.add(INFIX_OPERATOR_TO_DECLARATION[expression.operator])
 
-        if expression.value not in accumulators.symbol_list:
-            symbol_list.append(expression.value)
-
-        return CSymbolExpression(
-            symbol=expression.value,
-            symbol_list_index=accumulators.symbol_list.index(expression.value),
-        )
-
-    if isinstance(expression, parsing.FurStringLiteralExpression):
-        value = expression.value
-
-        try:
-            index = accumulators.string_literal_list.index(value)
-        except ValueError:
-            index = len(accumulators.string_literal_list)
-            accumulators.string_literal_list.append(value)
-
-        return CStringLiteral(index=index, value=value)
-
-    LITERAL_TYPE_MAPPING = {
-        parsing.FurIntegerLiteralExpression: CIntegerLiteral,
-    }
-
-    if type(expression) in LITERAL_TYPE_MAPPING:
-        return LITERAL_TYPE_MAPPING[type(expression)](value=expression.value)
-
-    if isinstance(expression, parsing.FurInfixExpression):
-        if expression.order == 'equality_level':
-            return transform_equality_level_expression(accumulators, expression)
+    return CFunctionCallForFurInfixOperator(
+        name=INFIX_OPERATOR_TO_DECLARATION[expression.operator].name,
+        left=transform_expression(accumulators, expression.left),
+        right=transform_expression(accumulators, expression.right),
+    )
 
-        INFIX_OPERATOR_TO_FUNCTION_NAME = {
-            '+':    'add',
-            '-':    'subtract',
-            '*':    'multiply',
-            '//':   'integerDivide',
-            '%':    'modularDivide',
-            'and':  'and',
-            'or':   'or',
-        }
+def transform_integer_literal_expression(accumulators, expression):
+    return CIntegerLiteral(value=expression.integer)
 
-        return CFunctionCallForFurInfixOperator(
-            name=INFIX_OPERATOR_TO_FUNCTION_NAME[expression.operator],
-            left=transform_expression(accumulators, expression.left),
-            right=transform_expression(accumulators, expression.right),
-        )
+def transform_negation_expression(accumulators, expression):
+    return CNegationExpression(
+        value=transform_expression(accumulators, expression.internal_expression),
+    )
 
-    # TODO Handle all possible types in this form
+def transform_expression(accumulators, expression):
+    # TODO Clean up handlers for parsing expressions
     return {
+        parsing.FurInfixExpression: transform_infix_expression,
+        parsing.FurIntegerLiteralExpression: transform_integer_literal_expression,
+        parsing.FurNegationExpression: transform_negation_expression,
+        parsing.FurStringLiteralExpression: transform_string_literal_expression,
+        normalization.NormalFunctionCallExpression: transform_function_call_expression,
+        normalization.NormalInfixExpression: transform_infix_expression,
+        normalization.NormalIntegerLiteralExpression: transform_integer_literal_expression,
+        normalization.NormalNegationExpression: transform_negation_expression,
+        normalization.NormalStringLiteralExpression: transform_string_literal_expression,
+        normalization.NormalSymbolExpression: transform_symbol_expression,
         normalization.NormalVariableExpression: transform_variable_expression,
     }[type(expression)](accumulators, expression)
 
 def transform_symbol_assignment_statement(accumulators, assignment_statement):
     # TODO Check that target is not a builtin
-    if assignment_statement.target not in accumulators.symbol_list:
+    try:
+        symbol_list_index = accumulators.symbol_list.index(assignment_statement.target)
+    except ValueError:
+        symbol_list_index = len(accumulators.symbol_list)
         accumulators.symbol_list.append(assignment_statement.target)
 
     return CSymbolAssignmentStatement(
         target=assignment_statement.target,
-        target_symbol_list_index=accumulators.symbol_list.index(assignment_statement.target),
+        target_symbol_list_index=symbol_list_index,
         expression=transform_expression(
             accumulators,
             assignment_statement.expression,
         ),
     )
 
-def transform_negation_expression(accumulators, negation_expression):
-    return CNegationExpression(
-        value=transform_expression(accumulators, negation_expression.value),
+def transform_function_call_expression(accumulators, function_call):
+    # TODO Use the symbol from SYMBOL LIST
+    return CFunctionCallExpression(
+        function_expression=transform_expression(accumulators, function_call.function_expression),
+        argument_count=function_call.argument_count,
+        argument_items=transform_expression(accumulators, function_call.argument_items),
     )
 
-def transform_function_call_expression(accumulators, function_call):
-    if function_call.function.value in BUILTINS.keys():
-        # TODO Check that the builtin is actually callable
-        accumulators.builtin_set.add(function_call.function.value)
-
-        return CFunctionCallExpression(
-            name='builtin$' + function_call.function.value,
-            arguments=tuple(
-                transform_expression(accumulators, arg)
-                for arg in function_call.arguments
-            ),
-        )
+def transform_expression_statement(accumulators, statement):
+    return CExpressionStatement(
+        expression=transform_expression(accumulators, statement.expression),
+    )
 
-    raise Exception()
+def transform_if_else_statement(accumulators, statement):
+    return CIfElseStatement(
+        condition_expression=transform_expression(accumulators, statement.condition_expression),
+        if_statement_list=tuple(transform_statement(accumulators, s) for s in statement.if_statement_list),
+        else_statement_list=tuple(transform_statement(accumulators, s) for s in statement.else_statement_list),
+    )
 
-def transform_expression_statement(accumulators, statement):
-    expression = {
-        parsing.FurFunctionCallExpression: transform_function_call_expression,
-        normalization.NormalFunctionCallExpression: transform_function_call_expression,
-    }[type(statement.expression)](accumulators, statement.expression)
+def transform_array_variable_initialization_statement(accumulators, statement):
+    return CArrayVariableInitializationStatement(
+        variable=statement.variable,
+        items=tuple(transform_expression(accumulators, i) for i in statement.items),
+    )
 
-    return CExpressionStatement(
-        expression=expression,
+def transform_variable_initialization_statement(accumulators, statement):
+    return CVariableInitializationStatement(
+        variable=statement.variable,
+        expression=transform_expression(accumulators, statement.expression),
     )
 
-def transform_variable_assignment_statement(accumulators, statement):
-    return CVariableAssignmentStatement(
+def transform_variable_reassignment_statement(accumulators, statement):
+    return CVariableReassignmentStatement(
         variable=statement.variable,
         expression=transform_expression(accumulators, statement.expression),
     )
 
+def transform_function_definition_statement(accumulators, statement):
+    # TODO Allow defining the same function in different contexts
+    if any(fd.name == statement.name for fd in accumulators.function_definition_list):
+        raise Exception('A function with name "{}" already exists'.format(statement.name))
+
+    # TODO Add argument names to the symbol table
+    accumulators.function_definition_list.append(CFunctionDefinition(
+        name=statement.name,
+        argument_name_list=statement.argument_name_list,
+        statement_list=tuple(transform_statement(accumulators, s) for s in statement.statement_list)
+    ))
+
+    return CFunctionDeclaration(name=statement.name)
+
 def transform_statement(accumulators, statement):
     return {
-        parsing.FurAssignmentStatement: transform_symbol_assignment_statement,
         parsing.FurExpressionStatement: transform_expression_statement,
-        normalization.NormalVariableAssignmentStatement: transform_variable_assignment_statement,
+        normalization.NormalArrayVariableInitializationStatement: transform_array_variable_initialization_statement,
+        normalization.NormalAssignmentStatement: transform_symbol_assignment_statement,
         normalization.NormalExpressionStatement: transform_expression_statement,
+        normalization.NormalFunctionDefinitionStatement: transform_function_definition_statement,
+        normalization.NormalIfElseStatement: transform_if_else_statement,
+        normalization.NormalVariableInitializationStatement: transform_variable_initialization_statement,
+        normalization.NormalVariableReassignmentStatement: transform_variable_reassignment_statement,
     }[type(statement)](accumulators, statement)
 
 
@@ -279,6 +357,8 @@ Accumulators = collections.namedtuple(
     'Accumulators',
     [
         'builtin_set',
+        'function_definition_list',
+        'operator_set',
         'symbol_list',
         'string_literal_list',
     ],
@@ -287,6 +367,8 @@ Accumulators = collections.namedtuple(
 def transform(program):
     accumulators = Accumulators(
         builtin_set=set(),
+        function_definition_list=[],
+        operator_set=set(),
         symbol_list=[],
         string_literal_list=[],
     )
@@ -295,6 +377,11 @@ def transform(program):
         transform_statement(accumulators, statement) for statement in program.statement_list
     ]
 
+    # This prevents warnings about normalized variables being entire C statements
+    last_statement = statement_list[-1]
+    if isinstance(last_statement, normalization.NormalExpressionStatement) and isinstance(last_statement.expression, normalization.NormalVariableExpression):
+        del statement_list[-1]
+
     standard_library_set = set()
     for builtin in accumulators.builtin_set:
         for standard_library in BUILTINS[builtin]:
@@ -302,6 +389,8 @@ def transform(program):
 
     return CProgram(
         builtin_set=accumulators.builtin_set,
+        function_definition_list=accumulators.function_definition_list,
+        operator_declarations=tuple(sorted(accumulators.operator_set)),
         statements=statement_list,
         standard_libraries=standard_library_set,
         string_literal_list=accumulators.string_literal_list,