Re: [Boost-users] [Spirit] Parser omits certain characters

Subject: Re: [Boost-users] [Spirit] Parser omits certain characters
From: TONGARI J (tongari95_at_[hidden])
Date: 2013-10-31 22:42:43

2013/11/1 beet <r.berlich_at_gemfony.eu>

> Dear all,
>
> For all of the following, please see the attached test-case.
>
> I would like to specify certain characterstics of variables in the
> following way: d(MY_DPAR_01,-10.3,12.8,100) . So in this case there is a
> type-identifyer (d stands for "double") and then, in parantheses, a
> variable name (or alternatively an index), a lower and upper boundary
> and some integer parameter. What is contained in the list depends on the
> parameter type.
>
> It should then be possible to specify any number of variables, including
> their properties, in a comma-separated list.
>
> So I need to dissect a string like the following:
>
> "d(MY_DPAR_01,-10.3,12.8,100), d(0,-10.3,12.8,100), i(SOME_IPAR_17,
> 0,5), b(SOME_BPAR)"
>
> The first step, as I see it, is to seperate the "outer" list and to
> store each variable description in a boost::tuple<char, std::string>,
> where the char holds the type identifier and the std::string the part
> inside the parantheses. Then, in the second step, I want to parse that
> string according to what is expected for this particular type.
>
> I have now run into the problem that the following rule in Boost.Spirit
> "swallows" all non-alphanumeric characters.
>
> qi::rule<std::string::const_iterator, std::string(), ascii::space_type>
> varSpec = +(alnum | '_' | ',' | '.' | '+' | '-');
>

Note '_' is actually qi::lit('_'), which exposes *no* attribute, unlike
qi::char_ (and qi::alnum, etc) which gives you a char.
I'd suggest +qi::char_("a-zA-Z0-9_,.+-") for varSpec.

HTH