Adapting an empty struct for Boost Fusion

Question

I have an empty struct:

struct MyStruct {};

I want to adapt this to be used by Boost Fusion. Ordinarily I would use BOOST_FUSION_ADAPT_STRUCT, but this macro requires two parameters to name the struct and list its fields. Is there anyway to tell the macro that the fields are non-existent?

Motivation: I am using Boost Spirit to define a parser. The struct is for a boost::variant that is then passed to boost::apply_visitor(). Some of the other items in the variant given the boost::fusion::for_each() treatment.

score 4 · Accepted Answer · answered Sep 16 '13 at 17:50

4

I tried passing /**/ as the second parameter and it compiled for me (g++-4.6.2).

    BOOST_FUSION_ADAPT_STRUCT(MyStruct, /**/);

answered Sep 16 '13 at 17:50

SirGuy

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Visual C++ v140 does refuses to eat it though. – Lofty Lion Apr 18 '16 at 11:54
@LoftyLion Unfortunately I don't have MSVC to test this, you may have better luck asking a new question. – SirGuy Apr 18 '16 at 15:25

score 0 · Answer 2 · answered Sep 16 '13 at 15:47

0

Try passing BOOST_PP_EMPTY. No guarantees that it will work, but given the implementation it seems likely.

answered Sep 16 '13 at 15:47

Sebastian Redl

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I'm getting an error `'BOOST_PP_IIF_0' does not name a type`. Thanks for the suggestion anyway though. – chrisaycock Sep 16 '13 at 16:14

Adapting an empty struct for Boost Fusion

2 Answers2