Re: [Qi] Bizarro Qi results coming from compiler

On Wed, Nov 29, 2017 at 2:49 PM, Seth <[email protected]> wrote:
> On 29-11-17 19:31, Michael Powell wrote:
>> Particularly the idiotic comments concerning:
>
> Let's try to stay civilized. These are the people trying to help you. I
> can see you're frustrated, but let's not detract from the people trying
> to help? Thank you.

Well, it **is** frustrating when I am doing precisely what the comment
suggests I should be doing, idiotic or not.

> Also, it holds water just fine (of course). You declared the accepted
> skipper as typename Skipper = my_skipper<Iterator>. And yet you pass in
> `boost::spirit::qi::ascii::space`. That's of type
> `boost::spirit::qi::ascii::space_type`. Not the same type.

Excuse me? space *is* of type space_type.

boost::spirit::qi::ascii::space is just an alias to
boost::spirit::ascii::space, which is of type
boost::spirit::ascii::space_type. Or is my IntelliSense lying to me?

That being established, I should be able to specify the skipper, just
besides the *default* template argument, no? Why would that be a
problem?

Let's reason it through, shall we? i.e.

template<typename Iterator, typename Skipper = qi::ascii::space_type>
struct my_grammar : qi::grammar<Iterator, ..., Skipper> {
  // ...
};

All this means is that Skipper has a *default* type specification when
the end user did not specify one: i.e.

my_grammar<std::string:const_iterator /* with default skipper type */ > g;

So, why is that a problem for:

const auto& parse_ = [&g](std::string const& s) {
  auto it = s.begin();
  auto const parsed = qi::phrase_parse(it, s.end(), g, qi::ascii::space);
  // ??? in effect, the same as saying: qi::phrase_parse(it, s.end(),
g, decltype(g)::skipper_type());
  REQUIRE(parsed);
  REQUIRE(it == s.end());
};

That is, unless there is something else about <space> that isn't the
same, but I can't imagine what that is?

> Try passing in the required skipper type:
> http://coliru.stacked-crooked.com/a/78e51182445391c6
>
>
> Cheers, Seth
>

------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot