Prevent assignment to a builtin variable
[fur] / transformation.py
1 import collections
2
3 import normalization
4 import parsing
5
6 CIntegerLiteral = collections.namedtuple(
7     'CIntegerLiteral',
8     [
9         'value',
10     ],
11 )
12
13 CStringLiteral = collections.namedtuple(
14     'CStringLiteral',
15     [
16         'index',
17         'value',
18     ],
19 )
20
21 CConstantExpression = collections.namedtuple(
22     'CConstantExpression',
23     [
24         'value'
25     ],
26 )
27
28 CVariableExpression = collections.namedtuple(
29     'CVariableExpression',
30     [
31         'variable',
32     ],
33 )
34
35 CSymbolExpression = collections.namedtuple(
36     'CSymbolExpression',
37     [
38         'symbol',
39         'symbol_list_index',
40     ],
41 )
42
43 CNegationExpression = collections.namedtuple(
44     'CNegationExpression',
45     [
46         'value',
47     ],
48 )
49
50 CFunctionCallForFurInfixOperator = collections.namedtuple(
51     'CFunctionCallForFurInfixOperator',
52     [
53         'name',
54         'left',
55         'right',
56     ],
57 )
58
59 CFunctionCallExpression = collections.namedtuple(
60     'CFunctionCallExpression',
61     [
62         'name',
63         'argument_count',
64         'argument_items',
65     ],
66 )
67
68 CSymbolAssignmentStatement = collections.namedtuple(
69     'CSymbolAssignmentStatement',
70     [
71         'target',
72         'target_symbol_list_index',
73         'expression',
74     ],
75 )
76
77 CArrayVariableInitializationStatement = collections.namedtuple(
78     'CArrayVariableInitializationStatement',
79     [
80         'variable',
81         'items',
82     ],
83 )
84
85 CVariableInitializationStatement = collections.namedtuple(
86     'CVariableInitializationStatement',
87     [
88         'variable',
89         'expression',
90     ],
91 )
92
93 CVariableReassignmentStatement = collections.namedtuple(
94     'CVariableReassignmentStatement',
95     [
96         'variable',
97         'expression',
98     ],
99 )
100
101 CExpressionStatement = collections.namedtuple(
102     'CExpressionStatement',
103     [
104         'expression',
105     ],
106 )
107
108 CIfElseStatement = collections.namedtuple(
109     'CIfElseStatement',
110     [
111         'condition_expression',
112         'if_statements',
113         'else_statements',
114     ],
115 )
116
117 CFunctionDeclaration = collections.namedtuple(
118     'CFunctionDeclaration',
119     [
120         'name',
121     ],
122 )
123
124 CFunctionDefinition = collections.namedtuple(
125     'CFunctionDefinition',
126     [
127         'name',
128         'argument_name_list',
129         'statement_list',
130     ],
131 )
132
133 CProgram = collections.namedtuple(
134     'CProgram',
135     [
136         'builtin_set',
137         'function_definition_list',
138         'operator_declarations',
139         'statements',
140         'standard_libraries',
141         'string_literal_list',
142         'symbol_list',
143     ],
144 )
145
146 BUILTINS = {
147     'false':    [],
148     'pow':      ['math.h'],
149     'print':    ['stdio.h'],
150     'true':     [],
151 }
152
153 def transform_variable_expression(accumulators, expression):
154     return CVariableExpression(variable=expression.variable)
155
156 def transform_string_literal(accumulators, expression):
157     value = expression.value
158
159     try:
160         index = accumulators.string_literal_list.index(value)
161     except ValueError:
162         index = len(accumulators.string_literal_list)
163         accumulators.string_literal_list.append(value)
164
165     return CStringLiteral(index=index, value=value)
166
167 def transform_symbol_expression(accumulators, expression):
168     if expression.value in ['true', 'false']:
169         return CConstantExpression(value=expression.value)
170
171     try:
172         symbol_list_index = accumulators.symbol_list.index(expression.value)
173     except ValueError:
174         symbol_list_index = len(accumulators.symbol_list)
175         accumulators.symbol_list.append(expression.value)
176
177     return CSymbolExpression(
178         symbol=expression.value,
179         symbol_list_index=symbol_list_index,
180     )
181
182 CInfixDeclaration = collections.namedtuple(
183     'CInfixDeclaration',
184     [
185         'name',
186         'in_type',
187         'out_type',
188         'operator',
189     ],
190 )
191
192 INFIX_OPERATOR_TO_DECLARATION = {
193     '+':    CInfixDeclaration(name='add', in_type='integer', out_type='integer', operator='+'),
194     '-':    CInfixDeclaration(name='subtract', in_type='integer', out_type='integer', operator='-'),
195     '*':    CInfixDeclaration(name='multiply', in_type='integer', out_type='integer', operator='*'),
196     '//':   CInfixDeclaration(name='integerDivide', in_type='integer', out_type='integer', operator='/'),
197     '%':    CInfixDeclaration(name='modularDivide', in_type='integer', out_type='integer', operator='%'),
198     'and':  CInfixDeclaration(name='and', in_type='boolean', out_type='boolean', operator='&&'),
199     'or':   CInfixDeclaration(name='or', in_type='boolean', out_type='boolean', operator='||'),
200     '==':   CInfixDeclaration(name='equals', in_type='integer', out_type='boolean', operator='=='),
201     '!=':   CInfixDeclaration(name='notEquals', in_type='integer', out_type='boolean', operator='!='),
202     '<=':   CInfixDeclaration(name='lessThanOrEqual', in_type='integer', out_type='boolean', operator='<='),
203     '>=':   CInfixDeclaration(name='greaterThanOrEqual', in_type='integer', out_type='boolean', operator='>='),
204     '<':    CInfixDeclaration(name='lessThan', in_type='integer', out_type='boolean', operator='<'),
205     '>':    CInfixDeclaration(name='greaterThan', in_type='integer', out_type='boolean', operator='>'),
206 }
207
208 def transform_comparison_level_expression(accumulators, expression):
209     accumulators.operator_set.add(INFIX_OPERATOR_TO_DECLARATION[expression.operator])
210
211     # Transform expressions like 1 < 2 < 3 into expressions like 1 < 2 && 2 < 3
212     if isinstance(expression.left, parsing.FurInfixExpression) and expression.left.order == 'comparison_level':
213         left = transform_comparison_level_expression(
214             accumulators,
215             expression.left
216         )
217
218         middle = left.right
219
220         right = transform_expression(
221             accumulators,
222             expression.right,
223         )
224
225         # TODO Don't evaluate the middle expression twice
226         return CFunctionCallForFurInfixOperator(
227             name='and',
228             left=left,
229             right=CFunctionCallForFurInfixOperator(
230                 name=INFIX_OPERATOR_TO_DECLARATION[expression.operator].name,
231                 left=middle,
232                 right=right,
233             ),
234         )
235
236     return CFunctionCallForFurInfixOperator(
237         name=INFIX_OPERATOR_TO_DECLARATION[expression.operator].name,
238         left=transform_expression(accumulators, expression.left),
239         right=transform_expression(accumulators, expression.right),
240     )
241
242 def transform_infix_expression(accumulators, expression):
243     if expression.order == 'comparison_level':
244         return transform_comparison_level_expression(accumulators, expression)
245
246     accumulators.operator_set.add(INFIX_OPERATOR_TO_DECLARATION[expression.operator])
247
248     return CFunctionCallForFurInfixOperator(
249         name=INFIX_OPERATOR_TO_DECLARATION[expression.operator].name,
250         left=transform_expression(accumulators, expression.left),
251         right=transform_expression(accumulators, expression.right),
252     )
253
254 def transform_integer_literal_expression(accumulators, expression):
255     return CIntegerLiteral(value=expression.value)
256
257 def transform_negation_expression(accumulators, expression):
258     return CNegationExpression(
259         value=transform_expression(accumulators, expression.internal_expression),
260     )
261
262 def transform_expression(accumulators, expression):
263     # TODO Clean up handlers for parsing expressions
264     return {
265         parsing.FurFunctionCallExpression: transform_function_call_expression,
266         parsing.FurInfixExpression: transform_infix_expression,
267         parsing.FurIntegerLiteralExpression: transform_integer_literal_expression,
268         parsing.FurNegationExpression: transform_negation_expression,
269         parsing.FurStringLiteralExpression: transform_string_literal,
270         parsing.FurSymbolExpression: transform_symbol_expression,
271         normalization.NormalFunctionCallExpression: transform_function_call_expression,
272         normalization.NormalInfixExpression: transform_infix_expression,
273         normalization.NormalNegationExpression: transform_negation_expression,
274         normalization.NormalVariableExpression: transform_variable_expression,
275     }[type(expression)](accumulators, expression)
276
277 def transform_symbol_assignment_statement(accumulators, assignment_statement):
278     # TODO Check that target is not a builtin
279     try:
280         symbol_list_index = accumulators.symbol_list.index(assignment_statement.target)
281     except ValueError:
282         symbol_list_index = len(accumulators.symbol_list)
283         accumulators.symbol_list.append(assignment_statement.target)
284
285     return CSymbolAssignmentStatement(
286         target=assignment_statement.target,
287         target_symbol_list_index=symbol_list_index,
288         expression=transform_expression(
289             accumulators,
290             assignment_statement.expression,
291         ),
292     )
293
294 def transform_function_call_expression(accumulators, function_call):
295     if isinstance(function_call.function, parsing.FurSymbolExpression):
296         # TODO Move this check to transformation of symbol expressions so we can have builtins that aren't functions
297         if function_call.function.value in BUILTINS.keys():
298             # TODO Check that the builtin is actually callable
299             accumulators.builtin_set.add(function_call.function.value)
300
301     # TODO Use the symbol from SYMBOL LIST
302     return CFunctionCallExpression(
303         name=transform_expression(accumulators, function_call.function),
304         argument_count=function_call.argument_count,
305         argument_items=transform_expression(accumulators, function_call.argument_items),
306     )
307
308 def transform_expression_statement(accumulators, statement):
309     return CExpressionStatement(
310         expression=transform_expression(accumulators, statement.expression),
311     )
312
313 def transform_if_else_statement(accumulators, statement):
314     return CIfElseStatement(
315         condition_expression=transform_expression(accumulators, statement.condition_expression),
316         if_statements=tuple(transform_statement(accumulators, s) for s in statement.if_statements),
317         else_statements=tuple(transform_statement(accumulators, s) for s in statement.else_statements),
318     )
319
320 def transform_array_variable_initialization_statement(accumulators, statement):
321     return CArrayVariableInitializationStatement(
322         variable=statement.variable,
323         items=tuple(transform_expression(accumulators, i) for i in statement.items),
324     )
325
326 def transform_variable_initialization_statement(accumulators, statement):
327     return CVariableInitializationStatement(
328         variable=statement.variable,
329         expression=transform_expression(accumulators, statement.expression),
330     )
331
332 def transform_variable_reassignment_statement(accumulators, statement):
333     return CVariableReassignmentStatement(
334         variable=statement.variable,
335         expression=transform_expression(accumulators, statement.expression),
336     )
337
338 def transform_function_definition_statement(accumulators, statement):
339     # TODO Allow defining the same function in different contexts
340     if any(fd.name == statement.name for fd in accumulators.function_definition_list):
341         raise Exception('A function with name "{}" already exists'.format(statement.name))
342
343     # TODO Add argument names to the symbol table
344     accumulators.function_definition_list.append(CFunctionDefinition(
345         name=statement.name,
346         argument_name_list=statement.argument_name_list,
347         statement_list=tuple(transform_statement(accumulators, s) for s in statement.statement_list)
348     ))
349
350     return CFunctionDeclaration(name=statement.name)
351
352 def transform_statement(accumulators, statement):
353     return {
354         parsing.FurExpressionStatement: transform_expression_statement,
355         normalization.NormalArrayVariableInitializationStatement: transform_array_variable_initialization_statement,
356         normalization.NormalAssignmentStatement: transform_symbol_assignment_statement,
357         normalization.NormalExpressionStatement: transform_expression_statement,
358         normalization.NormalFunctionDefinitionStatement: transform_function_definition_statement,
359         normalization.NormalIfElseStatement: transform_if_else_statement,
360         normalization.NormalVariableInitializationStatement: transform_variable_initialization_statement,
361         normalization.NormalVariableReassignmentStatement: transform_variable_reassignment_statement,
362     }[type(statement)](accumulators, statement)
363
364
365 Accumulators = collections.namedtuple(
366     'Accumulators',
367     [
368         'builtin_set',
369         'function_definition_list',
370         'operator_set',
371         'symbol_list',
372         'string_literal_list',
373     ],
374 )
375
376 def transform(program):
377     accumulators = Accumulators(
378         builtin_set=set(),
379         function_definition_list=[],
380         operator_set=set(),
381         symbol_list=[],
382         string_literal_list=[],
383     )
384
385     statement_list = [
386         transform_statement(accumulators, statement) for statement in program.statement_list
387     ]
388
389     standard_library_set = set()
390     for builtin in accumulators.builtin_set:
391         for standard_library in BUILTINS[builtin]:
392             standard_library_set.add(standard_library)
393
394     return CProgram(
395         builtin_set=accumulators.builtin_set,
396         function_definition_list=accumulators.function_definition_list,
397         operator_declarations=tuple(sorted(accumulators.operator_set)),
398         statements=statement_list,
399         standard_libraries=standard_library_set,
400         string_literal_list=accumulators.string_literal_list,
401         symbol_list=accumulators.symbol_list,
402     )
403
404
405 if __name__ == '__main__':
406     import unittest
407
408     unittest.main()