Re: [Boost-users] BOOST_PP_SEQ_ENUM troubles

Subject: Re: [Boost-users] BOOST_PP_SEQ_ENUM troubles
From: Edward Diener (eldiener_at_[hidden])
Date: 2016-07-07 20:04:52

On 7/7/2016 6:05 PM, Cherotek Music wrote:
> Ah I got it to work with the following:
>
> #define SEQ_FORMATS BOOST_PP_VARIADIC_TO_SEQ(FORMATS)
> #define PASTE(l,r) l##r

BOOST_PP_CAT

> #define STRINGIZE(x) #x

BOOST_PP_STRINGIZE

> #define ARG_PAIR(x) {STRINGIZE(x), create<PASTE(x,File)>}
> #define NTH_ARG(z, n, data) ARG_PAIR(BOOST_PP_SEQ_ELEM(n, data))
> #define ARG_PAIRS BOOST_PP_ENUM(BOOST_PP_SEQ_SIZE(SEQ_FORMATS), NTH_ARG,
> SEQ_FORMATS)
>
> Thanks guys!

Great !

>
> On Thu, Jul 7, 2016 at 11:57 PM, Cherotek Music <cherotek_at_[hidden]
> <mailto:cherotek_at_[hidden]>> wrote:
>
>     Thanks for the suggestion but I still can't get it to work :(
>
>     #define SEQ_FORMATS BOOST_PP_VARIADIC_TO_SEQ(FORMATS)
>     #define ARG_PAIR(x) {#x, create<x##File>}
>     #define NTH_ARG(z, n, data) ARG_PAIR(BOOST_PP_SEQ_ELEM(n, data))
>     #define ARG_PAIRS BOOST_PP_ENUM(BOOST_PP_SEQ_SIZE(SEQ_FORMATS),
>     NTH_ARG, SEQ_FORMATS)
>
>     gives the following error:
>
>     test.h:14:63: error: pasting ")" and "File" does not give a valid
>     preprocessing token
>      #define NTH_ARG(z, n, data) ARG_PAIR(BOOST_PP_SEQ_ELEM(n, data))
>                                                                    ^
>     test.h:13:33: note: in definition of macro ‘ARG_PAIR’
>      #define ARG_PAIR(x) {#x, create<x##File>}
>
>     We're getting closer though
>
>     On Thu, Jul 7, 2016 at 6:19 PM, Mathias Gaunard
>     <mathias.gaunard_at_[hidden] <mailto:mathias.gaunard_at_[hidden]>>
>     wrote:
>
>         On 6 July 2016 at 22:27, Cherotek Music <cherotek_at_[hidden]
>         <mailto:cherotek_at_[hidden]>> wrote:
>
>             Hi,
>             I'm trying to make a macro chain that expands something like
>             this
>
>             *A, B, C*
>
>             into something like this
>
>             *{"A", create<AFile>}, {"B", create<BFile>}, {"C",
>             create<CFile>}*
>
>             This is what I have come up with
>
>             *#define FORMATS A, B, C // Add new formats here*
>             *#define SEQ_FORMATS BOOST_PP_VARIADIC_TO_SEQ(FORMATS)*
>             *#define ARG_PAIR(s, data, x) {#x, create<x##File>}*
>             *#define SEQ_ARG_PAIRS BOOST_PP_SEQ_TRANSFORM(ARG_PAIR, ~,
>             SEQ_FORMATS)*
>             *#define ARG_PAIRS BOOST_PP_SEQ_ENUM(SEQ_ARG_PAIRS)*
>
>
>         Use BOOST_PP_ENUM with BOOST_PP_SEQ_SIZE and BOOST_PP_SEQ_ELEM
>         instead of BOOST_PP_SEQ_TRANSFORM+BOOST_PP_SEQ_ENUM.
>
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>
>
>
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