[Proto] Stuck turning a complex gramamr action to a primitive trasnform
I tried to turn a complex grammar transform
:
struct grammar :
or_< ...
,bp::when< bp::nary_expr< bp::_, bp::vararg< grammar > >
, bp::_default< grammar >
(
_bp::functional::unpack_exprbp::tag::function(
push_front( bp::_
, bp::_make_terminal
(
some_type<
bp::tag_ofbp::_ >()
)
)
)
)
>
into a single primitive transform but I end up stuck cause it seems some
of those transform (make_terminal) don't follow
the classic proto::result_of/proto namespace acces to compute it's
return type and calling it. How should I handle these ?
My intuition was that the transform oeprator() will call the equivalent
function onto its expr parameters while its result
struct compute the result_of by chaining the transform result_of results.
Ultimately, I want this to be a tempalte trasnform that take some_type
as a parameter :
bp::when< bp::nary_expr< bp::_, bp::vararg< grammar > >
, traversal
joel wrote:
I tried to turn a complex grammar transform : struct grammar : or_< ...
,bp::when< bp::nary_expr< bp::_, bp::vararg< grammar > > , bp::_default< grammar > (
_bp::functional::unpack_exprbp::tag::function( push_front( bp::_ , bp::_make_terminal ( some_type< bp::tag_ofbp::_ >() ) ) ) ) >
into a single primitive transform but I end up stuck cause it seems some of those transform (make_terminal) don't follow the classic proto::result_of/proto namespace acces to compute it's return type and calling it.
I don't know what you mean. Are you referring to the fact that _make_terminal is not a primitive transform? It is a callable function object. Unfortunately, the _make_terminal name follows Proto's naming conventions for primitive transforms, even though it isn't. Is that what has thrown you off? -- Eric Niebler BoostPro Computing http://www.boostpro.com
Eric Niebler wrote:
I don't know what you mean. Are you referring to the fact that _make_terminal is not a primitive transform? It is a callable function object. Unfortunately, the _make_terminal name follows Proto's naming conventions for primitive transforms, even though it isn't. Is that what has thrown you off? Ah, seems so yes. So I have to take it's boost::result_of instead of seekign a non-existant result_of::make_terminal ?
If yes is my idea of composing ok ? -- ___________________________________________ Joel Falcou - Assistant Professor PARALL Team - LRI - Universite Paris Sud XI Tel : (+33)1 69 15 66 35
joel wrote:
Eric Niebler wrote:
I don't know what you mean. Are you referring to the fact that _make_terminal is not a primitive transform? It is a callable function object. Unfortunately, the _make_terminal name follows Proto's naming conventions for primitive transforms, even though it isn't. Is that what has thrown you off?
Ah, seems so yes. So I have to take it's boost::result_of instead of seekign a non-existant result_of::make_terminal ?
proto::_make_terminal is just a typedef for
proto::functional::make_terminal, which is itself a typedef for
proto::functional::make_exprproto::tag::terminal. If you're looking
for the corresponding result_of:: metafunction, you should use
proto::result_of::make_expr
If yes is my idea of composing ok ?
Sure. -- Eric Niebler BoostPro Computing http://www.boostpro.com
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joel