nvcc sometimes has trouble compiling complex template code such as is found in Boost, even if the code is only used in __host__ functions. When a file’s extension is .cpp, nvcc performs no parsing itself and instead forwards the code to the host compiler, which is why you observe different behavior depending on the file … Read more
Your example I don’t see how your sample requires any of this. Just reorder your branches, then realize that the short branch is just a special case of the qualified case with n=1: Live On Coliru¹ (or using X3 version if you prefer). The generic case Now, having mentioned x3, it has the capacity to … Read more
Update X3 version added First off, you fallen into a deep trap here: Qi rules don’t work with auto. Use qi::copy or just used qi::rule<>. Your program has undefined behaviour and indeed it crashed for me (valgrind pointed out where the dangling references originated). So, first off: const auto rule = qi::copy(qi::int_ >> ‘:’ >> … Read more
Thank you for a quick hint! I’ve just tried your code and unless I do something wrong … I get this output: Syntax error:abc 8.81 Parsed:-a atoken Syntax error:-b btoken Syntax error:-c ctoken Syntax error:-d dtoken – G. Civardi 2 hours ago Okay, so, I couldn’t leave it alone :/ Turns out there was Undefined … Read more
From what I gather, reading the source and the mailing list, Phoenix is not integrated into X3 at all: the reason being that c++14 makes most of it obsolete. I agree that this leaves a few spots where Qi used to have elegant solutions, e.g. eps(DEFERRED_CONDITION), lazy(*RULE_PTR) (the Nabialek trick), and indeed, this case. Spirit … Read more
It’s a bug in your code, nothing wrong with the compiler or the optimization levels. The cinch is with expression templates (like the ones used by Boost Proto, and hence by Boost Spirit). They are only valid to the end of their enclosing full expression [1] The canonical workaound is: BOOST_SPIRIT_AUTO(ana, *~qi::char_(‘*’) > +qi::char_(‘*’)); You … Read more
Mmm. I feel that we have discussed a few more details in chat than have been reflected in the question as it is. Let me entertain you with my ‘toy’ implementation, complete with test cases, of a grammar that will recognize <<macros>> like this, including nested expansion of the same. Notable features: Expansion is done … Read more
The reference to qq becomes dangling after leaving the constructor, so that is indeed a problem. qi::locals is the canonical way to keep local state inside parser expressions. Your other option would be to extend the lifetime of qq (by making it a member of the grammar class, e.g.). Lastly, you might be interested in … Read more
This is a quite infamous edge-case in Spirit. The problem is, special-case handling of single-element Fusion Sequences in Spirit breaks some abstractions. The usual workaround is to adapt the exposed-attribute side to be less-trivial: rule<It, single_member_struct()> r = eps >> XXX; // the `eps` is there to break the spell However, here that won’t work, … Read more
Spirit is a lot friendlier to compiletime-polymorphism typedef variant<Command1, Command2, Command3> Command; But, let’s suppose you really want to do the old-fashioned polymorphism thing… Just newing-up the polymorphic objects on the fly during parsing, however, is a sure-fire way to make your parser bloated with semantic actions create lot of memory leaks on back-tracking in … Read more