[Boost-users] [Preprocessor] MSVC nonstandard macro expansion workaround?

Subject: [Boost-users] [Preprocessor] MSVC nonstandard macro expansion workaround?
From: rleigh_at_[hidden]
Date: 2016-03-03 08:49:58

Hi folks,

I've been trying to get Boost.Preprocessor to run a nested for loop over 
two sequences to output nested switch blocks and case statements.  This 
works fine with GCC and clang.  Unfortunately it's broken with MSVC.  If 
anyone had any thoughts on what I might need to tweak to enable the code 
to work with MSVC, I'd be very appreciative.  Even if it's as nasty as a 
big ifdef with an alternative set of macros!

This is the test case:

--------
#include <boost/preprocessor.hpp>
#include <iostream>

#define LASERTYPE_VALUES 
(EXCIMER)(GAS)(METALVAPOR)(SOLIDSTATE)(DYE)(SEMICONDUCTOR)(FREEELECTRON)(OTHER)

enum LaserType
{
   BOOST_PP_SEQ_ENUM(LASERTYPE_VALUES)
};

#define PP_SEQ_FOR_EACH_R_ID() BOOST_PP_SEQ_FOR_EACH_R
#define PP_DEFER(x) x BOOST_PP_EMPTY()

#define LT_NESTED(maR, maToplevelType, maNestedType)                    
\
   std::cout << "Test nested: first=" << LaserType(maToplevelType) << " 
second=" << LaserType(maNestedType) << " \n";

#define LT_TOPLEVEL(maR, maUnused, maType)                              
\
   std::cout << "Test toplevel: " << LaserType(maType) << " \n";         
\
   PP_DEFER(PP_SEQ_FOR_EACH_R_ID)()(maR, LT_NESTED, maType, 
LASERTYPE_VALUES);

int main() {
   BOOST_PP_EXPAND(BOOST_PP_SEQ_FOR_EACH(LT_TOPLEVEL, %%, 
LASERTYPE_VALUES));
}
--------

On MSVC, I get this:

> cl /EHsc /I \path\to\boost-1_60 /Fe:test-pp.exe test-pp.cpp
Microsoft (R) C/C++ Optimizing Compiler Version 18.00.40629 for x64
Copyright (C) Microsoft Corporation.  All rights reserved.

test-pp.cpp
test-pp.cpp(22) : warning C4003: not enough actual parameters for macro 
'BOOST_PP_VARIADIC_ELEM_3'
test-pp.cpp(22) : warning C4003: not enough actual parameters for macro 
'BOOST_PP_BOOL'
test-pp.cpp(22) : warning C4003: not enough actual parameters for macro 
'BOOST_PP_BOOL_I'
test-pp.cpp(22) : warning C4003: not enough actual parameters for macro 
'BOOST_PP_VARIADIC_ELEM_2'
test-pp.cpp(22) : warning C4003: not enough actual parameters for macro 
'BOOST_PP_DEC'
test-pp.cpp(22) : warning C4003: not enough actual parameters for macro 
'BOOST_PP_DEC_I'
test-pp.cpp(22) : error C2065: 'BOOST_PP_SEQ_FOR_EACH_M' : undeclared 
identifier
test-pp.cpp(22) : error C2065: 'BOOST_PP_TUPLE_EAT_2' : undeclared 
identifier
test-pp.cpp(22) : error C2065: 'LT_NESTED' : undeclared identifier
test-pp.cpp(22) : error C2064: term does not evaluate to a function 
taking 1 arguments
test-pp.cpp(22) : error C2146: syntax error : missing ';' before 
identifier 'BOOST_PP_IIF_BOOST_PP_BOOL_'
test-pp.cpp(22) : error C3861: 'BOOST_PP_IIF_BOOST_PP_BOOL_': identifier 
not found
test-pp.cpp(22) : error C2065: 'BOOST_PP_FOR_3' : undeclared identifier
test-pp.cpp(22) : error C2065: 'BOOST_PP_TUPLE_EAT_4' : undeclared 
identifier
test-pp.cpp(22) : error C2059: syntax error : ','
test-pp.cpp(22) : error C3861: 'BOOST_PP_EXPAND': identifier not found
test-pp.cpp(22) : error C2065: 'BOOST_PP_FOR_4' : undeclared identifier
test-pp.cpp(22) : error C2065: 'BOOST_PP_FOR_5' : undeclared identifier
test-pp.cpp(22) : error C2065: 'BOOST_PP_FOR_6' : undeclared identifier
test-pp.cpp(22) : error C2065: 'BOOST_PP_FOR_7' : undeclared identifier
test-pp.cpp(22) : error C2065: 'BOOST_PP_FOR_8' : undeclared identifier
test-pp.cpp(22) : error C2065: 'BOOST_PP_FOR_9' : undeclared identifier
test-pp.cpp(22) : error C2065: 'BOOST_PP_FOR_10' : undeclared identifier

I've spent hours tweaking the testcase to try to make this work, but so 
far without success.  It doesn't help that I don't fully understand what 
specifically is broken with the MSVC preprocessor, or how to work around 
whatever is behaving in a non-stanadard way.

Many thanks,
Roger