message: XPath: Minor parsing refactoring
  Simplify function argument parsing by folding arg 0 parsing into the
  main loop, reuse expression parsing logic for unary expression
diff: @@ -11236,6 +11236,7 @@ PUGI__NS_BEGIN
  const char_t* value = alloc_string(_lexer.contents());
  xpath_ast_node* n = new (alloc_node()) xpath_ast_node(ast_string_constant, xpath_type_string, value);
  +
  _lexer.next();
  return n;
  @@ -11249,6 +11250,7 @@ PUGI__NS_BEGIN
  throw_error_oom();
  xpath_ast_node* n = new (alloc_node()) xpath_ast_node(ast_number_constant, xpath_type_number, value);
  +
  _lexer.next();
  return n;
  @@ -11268,14 +11270,14 @@ PUGI__NS_BEGIN
  throw_error("Unrecognized function call");
  _lexer.next();
  - if (_lexer.current() != lex_close_brace)
  - args[argc++] = parse_expression();
  -
  while (_lexer.current() != lex_close_brace)
  + {
  + if (argc > 0)
  {
  if (_lexer.current() != lex_comma)
  throw_error("No comma between function arguments");
  _lexer.next();
  + }
  xpath_ast_node* n = parse_expression();
  @@ -11561,7 +11563,8 @@ PUGI__NS_BEGIN
  while (PUGI__IS_CHARTYPE(*state, ct_space)) ++state;
  - if (*state != '(') return parse_location_path();
  + if (*state != '(')
  + return parse_location_path();
  // This looks like a function call; however this still can be a node-test. Check it.
  if (parse_node_test_type(_lexer.contents()) != nodetest_none)
  @@ -11594,9 +11597,9 @@ PUGI__NS_BEGIN
  _lexer.next();
  // precedence 7+ - only parses union expressions
  - xpath_ast_node* expr = parse_expression_rec(parse_path_or_unary_expression(), 7);
  + xpath_ast_node* n = parse_expression(7);
  - return new (alloc_node()) xpath_ast_node(ast_op_negate, xpath_type_number, expr);
  + return new (alloc_node()) xpath_ast_node(ast_op_negate, xpath_type_number, n);
  }
  else
  {
  @@ -11718,9 +11721,11 @@ PUGI__NS_BEGIN
  // | MultiplicativeExpr '*' UnaryExpr
  // | MultiplicativeExpr 'div' UnaryExpr
  // | MultiplicativeExpr 'mod' UnaryExpr
  - xpath_ast_node* parse_expression()
  + xpath_ast_node* parse_expression(int limit = 0)
  {
  - return parse_expression_rec(parse_path_or_unary_expression(), 0);
  + xpath_ast_node* n = parse_path_or_unary_expression();
  +
  + return parse_expression_rec(n, limit);
  }
  xpath_parser(const char_t* query, xpath_variable_set* variables, xpath_allocator* alloc, xpath_parse_result* result): _alloc(alloc), _lexer(query), _query(query), _variables(variables), _result(result)
  