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clean-up: simplify function-closure -- eliminate the 'apply' case

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This library header was developed at a time, where C++ had no built-in support
for so called "invokables"; `std::invoke` and `std::apply` were added much later;
So in that early version that was a significant technical hurdle to overcome.

seems like it might be possible to get rid of the TupleApplicator alltogether?
This commit is contained in:
Fischlurch 2025-06-05 01:18:59 +02:00
parent 1a2c2ededa
commit 400d0eb92e
4 changed files with 54 additions and 181 deletions
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151
src/lib/meta/function-closure.hpp
View file

@ -101,13 +101,6 @@ namespace func{
template<> //__________________________________
struct Apply<0> ///< Apply function without Arguments
{
template<typename RET, class FUN, class TUP>
static RET
invoke (FUN& f, TUP&)
{
return f ();
}
template<typename RET, class FUN, class TUP>
static RET
bind (FUN& f, TUP&)
@ -120,13 +113,6 @@ namespace func{
template<> //_________________________________
struct Apply<1> ///< Apply function with 1 Argument
{
template<typename RET, class FUN, class TUP>
static RET
invoke (FUN& f, TUP & arg)
{
return f (get<0>(arg));
}
template<typename RET, class FUN, class TUP>
static RET
bind (FUN& f, TUP & arg)
@ -139,15 +125,6 @@ namespace func{
template<> //_________________________________
struct Apply<2> ///< Apply function with 2 Arguments
{
template<typename RET, class FUN, class TUP>
static RET
invoke (FUN& f, TUP & arg)
{
return f ( get<0>(arg)
, get<1>(arg)
);
}
template<typename RET, class FUN, class TUP>
static RET
bind (FUN& f, TUP & arg)
@ -162,16 +139,6 @@ namespace func{
template<> //_________________________________
struct Apply<3> ///< Apply function with 3 Arguments
{
template<typename RET, class FUN, class TUP>
static RET
invoke (FUN& f, TUP & arg)
{
return f ( get<0>(arg)
, get<1>(arg)
, get<2>(arg)
);
}
template<typename RET, class FUN, class TUP>
static RET
bind (FUN& f, TUP & arg)
@ -187,17 +154,6 @@ namespace func{
template<> //_________________________________
struct Apply<4> ///< Apply function with 4 Arguments
{
template<typename RET, class FUN, class TUP>
static RET
invoke (FUN& f, TUP & arg)
{
return f ( get<0>(arg)
, get<1>(arg)
, get<2>(arg)
, get<3>(arg)
);
}
template<typename RET, class FUN, class TUP>
static RET
bind (FUN& f, TUP & arg)
@ -214,18 +170,6 @@ namespace func{
template<> //_________________________________
struct Apply<5> ///< Apply function with 5 Arguments
{
template<typename RET, class FUN, class TUP>
static RET
invoke (FUN& f, TUP & arg)
{
return f ( get<0>(arg)
, get<1>(arg)
, get<2>(arg)
, get<3>(arg)
, get<4>(arg)
);
}
template<typename RET, class FUN, class TUP>
static RET
bind (FUN& f, TUP & arg)
@ -243,19 +187,6 @@ namespace func{
template<> //_________________________________
struct Apply<6> ///< Apply function with 6 Arguments
{
template<typename RET, class FUN, class TUP>
static RET
invoke (FUN& f, TUP & arg)
{
return f ( get<0>(arg)
, get<1>(arg)
, get<2>(arg)
, get<3>(arg)
, get<4>(arg)
, get<5>(arg)
);
}
template<typename RET, class FUN, class TUP>
static RET
bind (FUN& f, TUP & arg)
@ -274,20 +205,6 @@ namespace func{
template<> //_________________________________
struct Apply<7> ///< Apply function with 7 Arguments
{
template<typename RET, class FUN, class TUP>
static RET
invoke (FUN& f, TUP & arg)
{
return f ( get<0>(arg)
, get<1>(arg)
, get<2>(arg)
, get<3>(arg)
, get<4>(arg)
, get<5>(arg)
, get<6>(arg)
);
}
template<typename RET, class FUN, class TUP>
static RET
bind (FUN& f, TUP & arg)
@ -307,21 +224,6 @@ namespace func{
template<> //_________________________________
struct Apply<8> ///< Apply function with 8 Arguments
{
template<typename RET, class FUN, class TUP>
static RET
invoke (FUN& f, TUP & arg)
{
return f ( get<0>(arg)
, get<1>(arg)
, get<2>(arg)
, get<3>(arg)
, get<4>(arg)
, get<5>(arg)
, get<6>(arg)
, get<7>(arg)
);
}
template<typename RET, class FUN, class TUP>
static RET
bind (FUN& f, TUP & arg)
@ -342,22 +244,6 @@ namespace func{
template<> //_________________________________
struct Apply<9> ///< Apply function with 9 Arguments
{
template<typename RET, class FUN, class TUP>
static RET
invoke (FUN& f, TUP & arg)
{
return f ( get<0>(arg)
, get<1>(arg)
, get<2>(arg)
, get<3>(arg)
, get<4>(arg)
, get<5>(arg)
, get<6>(arg)
, get<7>(arg)
, get<8>(arg)
);
}
template<typename RET, class FUN, class TUP>
static RET
bind (FUN& f, TUP & arg)
@ -516,8 +402,13 @@ namespace func{
BoundFunc bind (SIG& f) { return Apply<ARG_CNT>::template bind<BoundFunc> (f, params_); }
BoundFunc bind (function<SIG> const& f) { return Apply<ARG_CNT>::template bind<BoundFunc> (f, params_); }
Ret operator() (SIG& f) { return Apply<ARG_CNT>::template invoke<Ret> (f, params_); }
Ret operator() (function<SIG>& f) { return Apply<ARG_CNT>::template invoke<Ret> (f, params_); }
template<class FUN>
Ret
operator() (FUN&& f)
{
ASSERT_VALID_SIGNATURE (FUN,SIG);
return std::apply (forward<FUN> (f), params_);
}
};
@ -644,7 +535,7 @@ namespace func{
* @param arg value tuple, used to close function arguments starting from left
* @return new function object, holding copies of the values and using them at the
* closed arguments; on invocation, only the remaining arguments need to be supplied.
* @note BuildL, i.e. the TupleApplicator _must take its arguments by-value._ Any attempt
* @note BuildL, and consequently TupleApplicator _must take the arguments by-value._ Any attempt
* towards »perfect-forwarding« would be potentially fragile and not worth the effort,
* since the optimiser sees the operation as a whole.
* @todo 2/2025 However, the LeftReplacedArgs _could_ then possibly moved into the bind function,
@ -844,32 +735,6 @@ namespace func{
/* ========== function-style interface ============= */
/** build a TupleApplicator, which embodies the given
* argument tuple and can be used to apply them
* to various functions repeatedly.
*/
template<typename...ARG>
inline
typename _Sig<void, TySeq<ARG...>>::Applicator
tupleApplicator (std::tuple<ARG...>& args)
{
using Signature = typename _Sig<void,TySeq<ARG...>>::Type;
return TupleApplicator<Signature>{args};
}
/** apply the given function to the argument tuple
* @deprecated 11/23 meanwhile provided by the standard lib! */
template<typename SIG, typename...ARG>
inline
typename _Fun<SIG>::Ret
apply (SIG& f, std::tuple<ARG...>& args)
{
using Ret = typename _Fun<SIG>::Ret; //
using Signature = typename _Sig<Ret,TySeq<ARG...>>::Type; // Note: deliberately re-building the Signature Type
return TupleApplicator<Signature>{args} (f); // in order to get better error messages here
}
/** close the given function over all arguments,
* using the values from the argument tuple.
* @return a closure object, which can be

5
src/steam/control/command-op-closure.hpp
View file

@ -51,7 +51,6 @@ namespace control {
using lib::meta::_Fun;
using lib::meta::Tuple;
using lib::meta::BuildTupleAccessor;
using lib::meta::func::TupleApplicator;
using lib::meta::buildTuple;
using lib::meta::Nil;
@ -175,8 +174,8 @@ namespace control {
void
invoke (CmdFunctor const& unboundFunctor)
{
TupleApplicator<SIG> apply_this_arguments(params_);
apply_this_arguments (unboundFunctor.getFun<SIG>());
ArgTuple& paramTuple{params_};
std::apply (unboundFunctor.getFun<SIG>(), paramTuple);
}

29
tests/library/meta/function-closure-test.cpp
View file

@ -86,7 +86,6 @@ namespace test {
using func::TupleApplicator;
using func::FunctionClosure;
using func::closure;
using func::apply;
/*********************************************************************//**
@ -164,21 +163,15 @@ namespace test {
DUMPVAL (tup2);
DUMPVAL (tup3);
CHECK (-1 == Apply<0>::invoke<int> (fun0, tup0) );
CHECK (11 == Apply<1>::invoke<int> (fun1, tup1) );
CHECK (11+12 == Apply<2>::invoke<int> (fun2, tup2) );
CHECK (11+12+13 == Apply<3>::invoke<int> (fun3, tup3) );
CHECK (-1 == TupleApplicator<int()> (tup0) (fun0) );
CHECK (11 == TupleApplicator<int(int)> (tup1) (fun1) );
CHECK (11+12 == TupleApplicator<int(int,int)> (tup2) (fun2) );
CHECK (11+12+13 == TupleApplicator<int(int,int,int)> (tup3) (fun3) );
CHECK (-1 == apply(fun0, tup0) );
CHECK (11 == apply(fun1, tup1) );
CHECK (11+12 == apply(fun2, tup2) );
CHECK (11+12+13 == apply(fun3, tup3) );
CHECK (-1 == std::apply(fun0, tup0) );
CHECK (11 == std::apply(fun1, tup1) );
CHECK (11+12 == std::apply(fun2, tup2) );
CHECK (11+12+13 == std::apply(fun3, tup3) );
}
@ -194,21 +187,15 @@ namespace test {
function<int(int,int)> functor2 (fun2);
function<int(int,int,int)> functor3 (fun3);
CHECK (-1 == Apply<0>::invoke<int> (functor0, tup0) );
CHECK (11 == Apply<1>::invoke<int> (functor1, tup1) );
CHECK (11+12 == Apply<2>::invoke<int> (functor2, tup2) );
CHECK (11+12+13 == Apply<3>::invoke<int> (functor3, tup3) );
CHECK (-1 == TupleApplicator<int()> (tup0) (functor0) );
CHECK (11 == TupleApplicator<int(int)> (tup1) (functor1) );
CHECK (11+12 == TupleApplicator<int(int,int)> (tup2) (functor2) );
CHECK (11+12+13 == TupleApplicator<int(int,int,int)> (tup3) (functor3) );
CHECK (-1 == apply(functor0, tup0) );
CHECK (11 == apply(functor1, tup1) );
CHECK (11+12 == apply(functor2, tup2) );
CHECK (11+12+13 == apply(functor3, tup3) );
CHECK (-1 == std::apply(functor0, tup0) );
CHECK (11 == std::apply(functor1, tup1) );
CHECK (11+12 == std::apply(functor2, tup2) );
CHECK (11+12+13 == std::apply(functor3, tup3) );
}

50
wiki/thinkPad.ichthyo.mm
View file

@ -164238,7 +164238,7 @@ Since then others have made contributions, see the log for the history.</font></
</node>
</node>
<node COLOR="#435e98" CREATED="1748828247849" ID="ID_476644412" MODIFIED="1748869713383" TEXT="Verbindung mit Typelisten">
<node COLOR="#338800" CREATED="1749001830758" ID="ID_91346918" MODIFIED="1749007560980" TEXT="eigenst&#xe4;ndige Konstruktion von Type-Listen hinzuf&#xfc;gen">
<node COLOR="#338800" CREATED="1749001830758" ID="ID_91346918" MODIFIED="1749078634991" TEXT="eigenst&#xe4;ndige Konstruktion von Type-Listen hinzuf&#xfc;gen">
<richcontent TYPE="NOTE"><html>
<head/>
<body>
@ -164246,8 +164246,7 @@ Since then others have made contributions, see the log for the history.</font></
bisher wurde das durch Delegieren an die alte Loki-Implementierung bewerkstelligt; das nun direkt auf der Basis von Variadics zu machen, w&#228;re der zentrale Schritt, der das neue &#214;kosystem der variadischen Typlisten autonom macht (so da&#223; man am Ende die alte nicht-variadische Definition entfernen kann)
</p>
</body>
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<icon BUILTIN="button_ok"/>
</node>
@ -164261,8 +164260,7 @@ Since then others have made contributions, see the log for the history.</font></
in typeseq-util (etwas versteckt zwischen den Spezialisierungen von Prepend, was wiederum Vorraussetzung ist, so einen R&#252;ckweg konstruieren zu k&#246;nnen)
</p>
</body>
</html>
</richcontent>
</html></richcontent>
</node>
<node COLOR="#338800" CREATED="1748828427985" ID="ID_819357004" MODIFIED="1748869657923" TEXT="auch eine f&#xfc;r TySeq hinzuf&#xfc;gen">
<icon BUILTIN="button_ok"/>
@ -164276,8 +164274,7 @@ Since then others have made contributions, see the log for the history.</font></
d.h arbeitet ausschlie&#223;lich auf Typlisten und bezieht sich nirgends auf Typ-Sequenzen
</p>
</body>
</html>
</richcontent>
</html></richcontent>
<icon BUILTIN="button_ok"/>
<node BACKGROUND_COLOR="#c8c0b6" COLOR="#435e98" CREATED="1748900614743" ID="ID_516014802" MODIFIED="1748900632652" TEXT="durch Test belegt: funtioniert auch mit den neuen Type-Sequenzen">
<font NAME="SansSerif" SIZE="10"/>
@ -164297,8 +164294,7 @@ Since then others have made contributions, see the log for the history.</font></
es stellt n&#228;mllich nur auf einen nested&#160;&#160;X::List ab
</p>
</body>
</html>
</richcontent>
</html></richcontent>
</node>
<node CREATED="1748828781783" ID="ID_691444823" MODIFIED="1748828794388" TEXT="sollte also f&#xfc;r alle Varianten gleicherma&#xdf;en greifen"/>
<node BACKGROUND_COLOR="#eef0c5" COLOR="#990000" CREATED="1748888164617" ID="ID_145174722" MODIFIED="1748980951490" TEXT="sollte Tests ustellen auf Inline-Checks (mit _expect)">
@ -164345,7 +164341,7 @@ Since then others have made contributions, see the log for the history.</font></
</node>
<node CREATED="1748829890844" ID="ID_1803577911" MODIFIED="1748829894782" TEXT="view-spec-dsl"/>
</node>
<node CREATED="1748992492455" ID="ID_240022720" MODIFIED="1748992513597" TEXT="mu&#xdf; auf einen Schlag geschwenkt werden (Komplexit&#xe4;t)">
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@ -164372,9 +164368,35 @@ Since then others have made contributions, see the log for the history.</font></
...aber nur wenn's einfach geht; eigentlich ist das au&#223;erhalb vom Scope und k&#246;nnte auch sp&#228;ter mal gemacht werden (ist nur ein Implementierungsdetail), sofern die bestehende Impl mit den neuen Typlisten arbeitet
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@ -164436,7 +164458,7 @@ Since then others have made contributions, see the log for the history.</font></
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@ -164464,7 +164486,7 @@ Since then others have made contributions, see the log for the history.</font></
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