feat: new example generate ast from scratch

examples/generate_ast.py

@@ -0,0 +1,44 @@
+# -----------------------------------------------------------------
+# pycparser: generate_ast.py
+#
+# Tiny example of writing an AST from scratch to C code.
+#
+# Andre Ribeiro [https://github.com/Andree37]
+# License: BSD
+# -----------------------------------------------------------------
+from __future__ import print_function
+
+from pycparser import c_ast, c_generator
+
+
+# target C code:
+# int main() {
+#     return 0;
+# }
+
+
+def create_your_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__':
+    ast = create_your_ast()
+    print("|----------------------------------------|")
+    ast.show(offset=2)
+    print("|----------------------------------------|")
+    c_code = generate_c_code(ast)
+    print("C code: \n%s" % c_code)