Re: [boost] [spirit.lex] 9580

Subject: Re: [boost] [spirit.lex] 9580
From: Hartmut Kaiser (hartmut.kaiser_at_[hidden])
Date: 2014-01-29 07:03:46

> Can somebody take a look at bug #9580? It's a C++ puzzle. Two as if
> equivalent expressions demonstrate different behavior. This one
>     auto expr = (this->self("SOME_STATE") += someTokenDef); calls
> boost::proto::detail::exprns_::operator +=.
> 
> However this
>     auto lex_def = this->self("SOME_STATE");
>     auto expr = (lex_def += someTokenDef); calls
> boost::spirit::lex::detail::operator +=.
> 
> My guess is that it changes templates instantiaon order, but still I can't
> explain it and thus can't fix it.

The first has an rvalue as its left hand side operand, while the second one
uses an lvalue there. Not sure how to solve this after a cursory glance,
though.

Regards Hartmut
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