How to use the pycparserext.ext_c_parser.GnuCParser function in pycparserext

def visit_FuncDeclExt(self, node):
            visits['FuncDeclExt'][0] += 1
            NodeVisitor.generic_visit(self, node)

    src_gnu = """
    int func1(int a, int b) {
        __typeof__(a) _a = __builtin_types_compatible_p(long char, short int);
        __typeof__ (__typeof__ (char *)[4]) y;
        asm("rdtsc" : "=A" (val));
        __attribute__((unused)) static int c;
    }
    """
    import pycparserext.ext_c_parser as ext_c_parser

    parser = ext_c_parser.GnuCParser()
    ast = parser.parse(src_gnu)
    ast.show()
    TestVisitor().visit(ast)
    for visit_type, visit_num in visits.items():
        assert_msg = '{}: Should have visited {}, got {}'.format(
            visit_type, visit_num[1], visit_num[0])
        assert visit_num[0] == visit_num[1], assert_msg

def test_lvalue_gnu_statement_expression():
    src = """
      int func(int a) {
        int ret=(int)({; ; *(int*)&a;});
        return ret;
     }
    """

    from pycparserext.ext_c_parser import GnuCParser
    p = GnuCParser()
    ast = p.parse(src)
    ast.show()

    from pycparserext.ext_c_generator import GnuCGenerator
    print(GnuCGenerator().visit(ast))

def test_funky_header_code_2():
    src = """
        extern __inline int __attribute__ ((__nothrow__)) __signbitf (float __x)
         {
           int __m;
           if (__x == 0)
              __asm ("pmovmskb %1, %0" : "=r" (__m) : "x" (__x));
           else
              __asm ("pmovmskb %1, %0" : "=r" (__m) : "x" (__x));
           return __m & 0x8;
         }
        """

    from pycparserext.ext_c_parser import GnuCParser
    p = GnuCParser()
    ast = p.parse(src)
    ast.show()

    from pycparserext.ext_c_generator import GnuCGenerator
    print(GnuCGenerator().visit(ast))

def test_nesty_c_declarator():
    src = """
    struct a {
        int *b[1][1];
    };
    """

    from pycparserext.ext_c_parser import GnuCParser
    p = GnuCParser()
    ast = p.parse(src)
    ast.show()

def enumerate_pins(c_source_file, include_dirs, definitions):
    """
    Enumerate pins specified in PinNames.h, by looking for a PinName enum
    typedef somewhere in the file.
    """
    definitions += ['__attribute(x)__=', '__extension__(x)=', 'register=', '__IO=', 'uint32_t=unsigned int']

    gcc_args = ['-E', '-fmerge-all-constants']
    gcc_args += ['-I' + directory for directory in include_dirs]

    gcc_args += ['-D' + definition for definition in definitions]
    parsed_ast = parse_file(c_source_file,
                            use_cpp=True,
                            cpp_path='arm-none-eabi-gcc',
                            cpp_args=gcc_args,
                            parser=GnuCParser())

    # now, walk the AST
    visitor = TypeDeclVisitor(['PinName'])
    return visitor.visit(parsed_ast)