code.kerkeslager.com Git - fur/blob - transformation.py

   1 import collections
   2
   3 import parsing
   4
   5 CIntegerLiteral = collections.namedtuple(
   6     'CIntegerLiteral',
   7     [
   8         'value',
   9     ],
  10 )
  11
  12 CStringLiteral = collections.namedtuple(
  13     'CStringLiteral',
  14     [
  15         'value',
  16     ],
  17 )
  18
  19 CConstantExpression = collections.namedtuple(
  20     'CConstantExpression',
  21     [
  22         'value'
  23     ],
  24 )
  25
  26 CSymbolExpression = collections.namedtuple(
  27     'CSymbolExpression',
  28     [
  29         'symbol',
  30         'symbol_list_index',
  31     ],
  32 )
  33
  34 CNegationExpression = collections.namedtuple(
  35     'CNegationExpression',
  36     [
  37         'value',
  38     ],
  39 )
  40
  41 CFunctionCallForFurInfixOperator = collections.namedtuple(
  42     'CFunctionCallForFurInfixOperator',
  43     [
  44         'name',
  45         'left',
  46         'right',
  47     ],
  48 )
  49
  50 CFunctionCallExpression = collections.namedtuple(
  51     'CFunctionCallExpression',
  52     [
  53         'name',
  54         'arguments',
  55     ],
  56 )
  57
  58 CAssignmentStatement = collections.namedtuple(
  59     'CAssignmentStatement',
  60     [
  61         'target',
  62         'target_symbol_list_index',
  63         'expression',
  64     ],
  65 )
  66
  67 CProgram = collections.namedtuple(
  68     'CProgram',
  69     [
  70         'builtins',
  71         'statements',
  72         'standard_libraries',
  73         'symbol_list',
  74     ],
  75 )
  76
  77 EQUALITY_LEVEL_OPERATOR_TO_FUNCTION_NAME_MAPPING = {
  78     '==':   'equals',
  79     '!=':   'notEquals',
  80     '<=':   'lessThanOrEqual',
  81     '>=':   'greaterThanOrEqual',
  82     '<':    'lessThan',
  83     '>':    'greaterThan',
  84 }
  85
  86 def transform_equality_level_expression(builtin_dependencies, symbol_list, expression):
  87     # Transform expressions like 1 < 2 < 3 into expressions like 1 < 2 && 2 < 3
  88     if isinstance(expression.left, parsing.FurInfixExpression) and expression.left.order == 'equality_level':
  89         left = transform_equality_level_expression(
  90             builtin_dependencies,
  91             symbol_list,
  92             expression.left
  93         )
  94
  95         middle = left.right
  96
  97         right = transform_expression(
  98             builtin_dependencies,
  99             symbol_list,
 100             expression.right,
 101         )
 102
 103         # TODO Don't evaluate the middle expression twice
 104         return CFunctionCallForFurInfixOperator(
 105             name='and',
 106             left=left,
 107             right=CFunctionCallForFurInfixOperator(
 108                 name=EQUALITY_LEVEL_OPERATOR_TO_FUNCTION_NAME_MAPPING[expression.operator],
 109                 left=middle,
 110                 right=right,
 111             ),
 112         )
 113
 114     return CFunctionCallForFurInfixOperator(
 115         name=EQUALITY_LEVEL_OPERATOR_TO_FUNCTION_NAME_MAPPING[expression.operator],
 116         left=transform_expression(builtin_dependencies, symbol_list, expression.left),
 117         right=transform_expression(builtin_dependencies, symbol_list, expression.right),
 118     )
 119
 120 BUILTINS = {
 121     'false':    [],
 122     'pow':      ['math.h'],
 123     'print':    ['stdio.h'],
 124     'true':     [],
 125 }
 126
 127 def transform_expression(builtin_dependencies, symbol_list, expression):
 128     if isinstance(expression, parsing.FurParenthesizedExpression):
 129         # Parentheses can be removed because everything in the C output is explicitly parenthesized
 130         return transform_expression(builtin_dependencies, symbol_list, expression.internal)
 131
 132     if isinstance(expression, parsing.FurNegationExpression):
 133         return transform_negation_expression(builtin_dependencies, symbol_list, expression)
 134
 135     if isinstance(expression, parsing.FurFunctionCallExpression):
 136         return transform_function_call_expression(builtin_dependencies, symbol_list, expression)
 137
 138     if isinstance(expression, parsing.FurSymbolExpression):
 139         if expression.value in ['true', 'false']:
 140             return CConstantExpression(value=expression.value)
 141
 142         if expression.value not in symbol_list:
 143             symbol_list.append(expression.value)
 144
 145         return CSymbolExpression(
 146             symbol=expression.value,
 147             symbol_list_index=symbol_list.index(expression.value),
 148         )
 149
 150     LITERAL_TYPE_MAPPING = {
 151         parsing.FurIntegerLiteralExpression: CIntegerLiteral,
 152         parsing.FurStringLiteralExpression: CStringLiteral,
 153     }
 154
 155     if type(expression) in LITERAL_TYPE_MAPPING:
 156         return LITERAL_TYPE_MAPPING[type(expression)](value=expression.value)
 157
 158     if isinstance(expression, parsing.FurInfixExpression):
 159         if expression.order == 'equality_level':
 160             return transform_equality_level_expression(builtin_dependencies, symbol_list, expression)
 161
 162         INFIX_OPERATOR_TO_FUNCTION_NAME = {
 163             '+': 'add',
 164             '-': 'subtract',
 165             '*': 'multiply',
 166             '//': 'integerDivide',
 167             '%': 'modularDivide',
 168         }
 169
 170         return CFunctionCallForFurInfixOperator(
 171             name=INFIX_OPERATOR_TO_FUNCTION_NAME[expression.operator],
 172             left=transform_expression(builtin_dependencies, symbol_list, expression.left),
 173             right=transform_expression(builtin_dependencies, symbol_list, expression.right),
 174         )
 175
 176     raise Exception('Could not transform expression "{}"'.format(expression))
 177
 178 def transform_assignment_statement(builtin_dependencies, symbol_list, assignment_statement):
 179     # TODO Check that target is not a builtin
 180     if assignment_statement.target not in symbol_list:
 181         symbol_list.append(assignment_statement.target)
 182
 183     return CAssignmentStatement(
 184         target=assignment_statement.target,
 185         target_symbol_list_index=symbol_list.index(assignment_statement.target),
 186         expression=transform_expression(
 187             builtin_dependencies,
 188             symbol_list,
 189             assignment_statement.expression,
 190         ),
 191     )
 192
 193 def transform_negation_expression(builtin_dependencies, symbol_list, negation_expression):
 194     return CNegationExpression(
 195         value=transform_expression(builtin_dependencies, symbol_list, negation_expression.value),
 196     )
 197
 198 def transform_function_call_expression(builtin_dependencies, symbol_list, function_call):
 199     if function_call.function.value in BUILTINS.keys():
 200         # TODO Check that the builtin is actually callable
 201         builtin_dependencies.add(function_call.function.value)
 202
 203         return CFunctionCallExpression(
 204             name='builtin$' + function_call.function.value,
 205             arguments=tuple(
 206                 transform_expression(builtin_dependencies, symbol_list, arg)
 207                 for arg in function_call.arguments
 208             ),
 209         )
 210
 211     raise Exception()
 212
 213 def transform_statement(builtin_dependencies, symbol_list, statement):
 214     return {
 215         parsing.FurAssignmentStatement: transform_assignment_statement,
 216         parsing.FurFunctionCallExpression: transform_function_call_expression,
 217     }[type(statement)](builtin_dependencies, symbol_list, statement)
 218
 219 def transform(program):
 220     builtins = set()
 221     symbol_list = []
 222
 223     c_statements = [
 224         transform_statement(builtins, symbol_list, statement) for statement in program.statement_list
 225     ]
 226
 227     standard_libraries = set()
 228     for builtin in builtins:
 229         for standard_library in BUILTINS[builtin]:
 230             standard_libraries.add(standard_library)
 231
 232     return CProgram(
 233         builtins=builtins,
 234         statements=c_statements,
 235         standard_libraries=standard_libraries,
 236         symbol_list=symbol_list,
 237     )
 238
 239
 240 if __name__ == '__main__':
 241     import unittest
 242
 243     unittest.main()