# -----------------------------------------------------------------
# pycparser: func_defs_add_param.py
#
# Example of rewriting AST nodes to add parameters to function
# definitions. Adds an "int _hidden" to every function.
#
# Eli Bendersky [https://eli.thegreenplace.net/]
# License: BSD
# -----------------------------------------------------------------
import sys

sys.path.extend([".", ".."])

from pycparser import c_parser, c_ast, c_generator

text = r"""
void foo(int a, int b) {
}

void bar() {
}
"""


class ParamAdder(c_ast.NodeVisitor):
    def visit_FuncDecl(self, node: c_ast.FuncDecl) -> None:
        ty = c_ast.TypeDecl(
            declname="_hidden", quals=[], align=[], type=c_ast.IdentifierType(["int"])
        )
        newdecl = c_ast.Decl(
            name="_hidden",
            quals=[],
            align=[],
            storage=[],
            funcspec=[],
            type=ty,
            init=None,
            bitsize=None,
            coord=node.coord,
        )
        if node.args is not None:
            node.args.params.append(newdecl)
        else:
            node.args = c_ast.ParamList(params=[newdecl])


if __name__ == "__main__":
    parser = c_parser.CParser()
    ast = parser.parse(text)
    print("AST before change:")
    ast.show(offset=2)

    v = ParamAdder()
    v.visit(ast)

    print("\nAST after change:")
    ast.show(offset=2)

    print("\nCode after change:")
    generator = c_generator.CGenerator()
    print(generator.visit(ast))