Added support for comparison operators

[fur] / transformation.py

diff --git a/transformation.py b/transformation.py
index cdf8155..cd9d18d 100644 (file)
--- a/transformation.py
+++ b/transformation.py
@@ -16,6 +16,28 @@ CStringLiteral = collections.namedtuple(
     ],
 )
 
+CConstantExpression = collections.namedtuple(
+    'CConstantExpression',
+    [
+        'value'
+    ],
+)
+
+CSymbolExpression = collections.namedtuple(
+    'CSymbolExpression',
+    [
+        'symbol',
+        'symbol_list_index',
+    ],
+)
+
+CNegationExpression = collections.namedtuple(
+    'CNegationExpression',
+    [
+        'value',
+    ],
+)
+
 CAdditionExpression = collections.namedtuple(
     'CAdditionExpression',
     [
@@ -48,6 +70,63 @@ CIntegerDivisionExpression = collections.namedtuple(
     ],
 )
 
+CEqualityExpression = collections.namedtuple(
+    'CEqualityExpression',
+    [
+        'left',
+        'right',
+    ],
+)
+
+CInequalityExpression = collections.namedtuple(
+    'CInequalityExpression',
+    [
+        'left',
+        'right',
+    ],
+)
+
+CGreaterThanOrEqualExpression = collections.namedtuple(
+    'CGreaterThanOrEqualExpression',
+    [
+        'left',
+        'right',
+    ],
+)
+
+CLessThanOrEqualExpression = collections.namedtuple(
+    'CLessThanOrEqualExpression',
+    [
+        'left',
+        'right',
+    ],
+)
+
+CGreaterThanExpression = collections.namedtuple(
+    'CGreaterThanExpression',
+    [
+        'left',
+        'right',
+    ],
+)
+
+CLessThanExpression = collections.namedtuple(
+    'CLessThanExpression',
+    [
+        'left',
+        'right',
+    ],
+)
+
+CAndExpression = collections.namedtuple(
+    'CAndExpression',
+    [
+        'left',
+        'right',
+    ],
+)
+
+
 CModularDivisionExpression = collections.namedtuple(
     'CModularDivisionExpression',
     [
@@ -56,28 +135,102 @@ CModularDivisionExpression = collections.namedtuple(
     ],
 )
 
-CFunctionCallStatement = collections.namedtuple(
-    'CFunctionCallStatement',
+CFunctionCallExpression = collections.namedtuple(
+    'CFunctionCallExpression',
     [
         'name',
         'arguments',
     ],
 )
 
+CAssignmentStatement = collections.namedtuple(
+    'CAssignmentStatement',
+    [
+        'target',
+        'target_symbol_list_index',
+        'expression',
+    ],
+)
+
 CProgram = collections.namedtuple(
     'CProgram',
     [
         'builtins',
         'statements',
         'standard_libraries',
+        'symbol_list',
     ],
 )
 
+EQUALITY_LEVEL_TYPE_MAPPING = {
+    parsing.FurEqualityExpression: CEqualityExpression,
+    parsing.FurInequalityExpression: CInequalityExpression,
+    parsing.FurLessThanOrEqualExpression: CLessThanOrEqualExpression,
+    parsing.FurGreaterThanOrEqualExpression: CGreaterThanOrEqualExpression,
+    parsing.FurLessThanExpression: CLessThanExpression,
+    parsing.FurGreaterThanExpression: CGreaterThanExpression,
+}
+
+def transform_equality_level_expression(builtin_dependencies, symbol_list, expression):
+    # Transform expressions like 1 < 2 < 3 into expressions like 1 < 2 && 2 < 3
+    if type(expression.left) in EQUALITY_LEVEL_TYPE_MAPPING:
+        left = transform_equality_level_expression(
+            builtin_dependencies,
+            symbol_list,
+            expression.left
+        )
+
+        middle = left.right
+
+        right = transform_expression(
+            builtin_dependencies,
+            symbol_list,
+            expression.right,
+        )
+
+        # TODO Don't evaluate the middle expression twice
+        return CAndExpression(
+            left=left,
+            right=EQUALITY_LEVEL_TYPE_MAPPING[type(expression)](
+                left=middle,
+                right=right,
+            ),
+        )
+
+    return EQUALITY_LEVEL_TYPE_MAPPING[type(expression)](
+        left=transform_expression(builtin_dependencies, symbol_list, expression.left),
+        right=transform_expression(builtin_dependencies, symbol_list, expression.right),
+    )
+
 BUILTINS = {
-    'print': ['stdio.h.'],
+    'false':    [],
+    'pow':      ['math.h'],
+    'print':    ['stdio.h'],
+    'true':     [],
 }
 
-def transform_expression(builtin_dependencies, expression):
+def transform_expression(builtin_dependencies, symbol_list, expression):
+    if isinstance(expression, parsing.FurParenthesizedExpression):
+        # Parentheses can be removed because everything in the C output is explicitly parenthesized
+        return transform_expression(builtin_dependencies, symbol_list, expression.internal)
+
+    if isinstance(expression, parsing.FurNegationExpression):
+        return transform_negation_expression(builtin_dependencies, symbol_list, expression)
+
+    if isinstance(expression, parsing.FurFunctionCallExpression):
+        return transform_function_call_expression(builtin_dependencies, symbol_list, expression)
+
+    if isinstance(expression, parsing.FurSymbolExpression):
+        if expression.value in ['true', 'false']:
+            return CConstantExpression(value=expression.value)
+
+        if expression.value not in symbol_list:
+            symbol_list.append(expression.value)
+
+        return CSymbolExpression(
+            symbol=expression.value,
+            symbol_list_index=symbol_list.index(expression.value),
+        )
 
     LITERAL_TYPE_MAPPING = {
         parsing.FurIntegerLiteralExpression: CIntegerLiteral,
@@ -87,6 +240,9 @@ def transform_expression(builtin_dependencies, expression):
     if type(expression) in LITERAL_TYPE_MAPPING:
         return LITERAL_TYPE_MAPPING[type(expression)](value=expression.value)
 
+    if type(expression) in EQUALITY_LEVEL_TYPE_MAPPING:
+        return transform_equality_level_expression(builtin_dependencies, symbol_list, expression)
+
     INFIX_TYPE_MAPPING = {
         parsing.FurAdditionExpression: CAdditionExpression,
         parsing.FurSubtractionExpression: CSubtractionExpression,
@@ -96,26 +252,57 @@ def transform_expression(builtin_dependencies, expression):
     }
 
     return INFIX_TYPE_MAPPING[type(expression)](
-        left=transform_expression(builtin_dependencies, expression.left),
-        right=transform_expression(builtin_dependencies, expression.right),
+        left=transform_expression(builtin_dependencies, symbol_list, expression.left),
+        right=transform_expression(builtin_dependencies, symbol_list, expression.right),
+    )
+
+def transform_assignment_statement(builtin_dependencies, symbol_list, assignment_statement):
+    # TODO Check that target is not a builtin
+    if assignment_statement.target not in symbol_list:
+        symbol_list.append(assignment_statement.target)
+
+    return CAssignmentStatement(
+        target=assignment_statement.target,
+        target_symbol_list_index=symbol_list.index(assignment_statement.target),
+        expression=transform_expression(
+            builtin_dependencies,
+            symbol_list,
+            assignment_statement.expression,
+        ),
     )
 
-def transform_function_call_statement(builtin_dependencies, function_call):
-    if function_call.name in BUILTINS.keys():
-        builtin_dependencies.add(function_call.name)
+def transform_negation_expression(builtin_dependencies, symbol_list, negation_expression):
+    return CNegationExpression(
+        value=transform_expression(builtin_dependencies, symbol_list, negation_expression.value),
+    )
 
-        return CFunctionCallStatement(
-            name='builtin$' + function_call.name,
-            arguments=tuple(transform_expression(builtin_dependencies, arg) for arg in function_call.arguments),
+def transform_function_call_expression(builtin_dependencies, symbol_list, function_call):
+    if function_call.function.value in BUILTINS.keys():
+        # TODO Check that the builtin is actually callable
+        builtin_dependencies.add(function_call.function.value)
+
+        return CFunctionCallExpression(
+            name='builtin$' + function_call.function.value,
+            arguments=tuple(
+                transform_expression(builtin_dependencies, symbol_list, arg)
+                for arg in function_call.arguments
+            ),
         )
 
     raise Exception()
 
+def transform_statement(builtin_dependencies, symbol_list, statement):
+    return {
+        parsing.FurAssignmentStatement: transform_assignment_statement,
+        parsing.FurFunctionCallExpression: transform_function_call_expression,
+    }[type(statement)](builtin_dependencies, symbol_list, statement)
+
 def transform(program):
     builtins = set()
+    symbol_list = []
 
     c_statements = [
-        transform_function_call_statement(builtins, statement) for statement in program.statement_list
+        transform_statement(builtins, symbol_list, statement) for statement in program.statement_list
     ]
 
     standard_libraries = set()
@@ -127,6 +314,7 @@ def transform(program):
         builtins=builtins,
         statements=c_statements,
         standard_libraries=standard_libraries,
+        symbol_list=symbol_list,
     )