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# -----------------------------------------------------------------
# pycparser: construct_ast_from_scratch.py
#
# Tiny example of writing an AST from scratch to C code.
#
# Andre Ribeiro [https://github.com/Andree37]
# License: BSD
# -----------------------------------------------------------------
import sys
# This is not required if you've installed pycparser into
# your site-packages/ with setup.py
sys.path.extend(['.', '..'])
from pycparser import c_ast, c_generator
# target C code:
# int main() {
# return 0;
# }
def empty_main_function_ast():
constant_zero = c_ast.Constant(type='int', value='0')
return_node = c_ast.Return(expr=constant_zero)
compound_node = c_ast.Compound(block_items=[return_node])
type_decl_node = c_ast.TypeDecl(declname='main', quals=[],
type=c_ast.IdentifierType(names=['int']),
align=[])
func_decl_node = c_ast.FuncDecl(args=c_ast.ParamList([]),
type=type_decl_node)
func_def_node = c_ast.Decl(name='main', quals=[], storage=[], funcspec=[],
type=func_decl_node, init=None,
bitsize=None, align=[])
main_func_node = c_ast.FuncDef(decl=func_def_node, param_decls=None,
body=compound_node)
return main_func_node
def generate_c_code(my_ast):
generator = c_generator.CGenerator()
return generator.visit(my_ast)
if __name__ == '__main__':
main_function_ast = empty_main_function_ast()
print("|----------------------------------------|")
main_function_ast.show(offset=2)
print("|----------------------------------------|")
main_c_code = generate_c_code(main_function_ast)
print("C code: \n%s" % main_c_code)
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