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clean-up: simplify function-closure -- rebuild the 'bind' case

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...can now be formulated in a single function,
based on the apply-to-λ technique invented by David Vandervoorde.

WARNING: the rewritten version of BindToArgument<...>::reduced()
does not compile in the out-of-bounds case, revealing a possibly
long standing defect in the typelist-metafunction Splice
This commit is contained in:
Fischlurch 2025-06-05 03:19:03 +02:00
parent 400d0eb92e
commit 415e4746a6
4 changed files with 168 additions and 24 deletions
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39
src/lib/meta/function-closure.hpp
View file

@ -412,6 +412,20 @@ namespace func{
}; };
template<class FUN, class TUP, typename = enable_if_Tuple<TUP>>
auto
bindArgTuple (FUN&& fun, TUP&& tuple)
{
return std::apply ([functor = forward<FUN>(fun)]
(auto&&... args)
{
return std::bind (move(functor)
,forward<decltype(args)> (args) ...);
}
,std::forward<TUP> (tuple));
}
/** /**
* Closing a function over its arguments. * Closing a function over its arguments.
@ -429,11 +443,11 @@ namespace func{
function<Ret(void)> closure_; function<Ret(void)> closure_;
public: public:
FunctionClosure (SIG& f, Tuple<Args>& arg) FunctionClosure (SIG& f, Tuple<Args>& args)
: closure_(TupleApplicator<SIG>(arg).bind(f)) : closure_{bindArgTuple (f, args)}
{ } { }
FunctionClosure (function<SIG> const& f, Tuple<Args>& arg) FunctionClosure (function<SIG> const& f, Tuple<Args>& args)
: closure_(TupleApplicator<SIG>(arg).bind(f)) : closure_{bindArgTuple (f, args)}
{ } { }
Ret operator() () { return closure_(); } Ret operator() () { return closure_(); }
@ -535,17 +549,18 @@ namespace func{
* @param arg value tuple, used to close function arguments starting from left * @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 * @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. * closed arguments; on invocation, only the remaining arguments need to be supplied.
* @note BuildL, and consequently TupleApplicator _must take the arguments by-value._ Any attempt * @note BuildL, and consequently std::bind _must take the arguments by-value._ Any attempt
* towards »perfect-forwarding« would be potentially fragile and not worth the effort, * towards »perfect-forwarding« would be potentially fragile and not worth the effort,
* since the optimiser sees the operation as a whole. * since the optimiser sees the operation as a whole.
* @todo 2/2025 However, the LeftReplacedArgs _could_ then possibly moved into the bind function, * @todo 2/2025 However, the LeftReplacedArgs _could_ then possibly moved into the bind function,
* as could the functor, once we replace the Apply-template by STDLIB features. * as could the functor, once we replace the Apply-template by STDLIB features.
* @todo 5/2025 seems indeed we could perfect-forward everything into the binder object.
*/ */
static LeftReducedFunc static LeftReducedFunc
bindFront (SIG const& f, Tuple<ValTypes> arg) bindFront (SIG const& f, Tuple<ValTypes> arg)
{ {
LeftReplacedArgs params {BuildL(std::move(arg))}; LeftReplacedArgs params {BuildL(std::move(arg))};
return func::Apply<ARG_CNT>::template bind<LeftReducedFunc> (f, params); return bindArgTuple (f, params);
} }
/** do a partial function application, closing the last arguments<br/> /** do a partial function application, closing the last arguments<br/>
@ -560,7 +575,7 @@ namespace func{
bindBack (SIG const& f, Tuple<ValTypes> arg) bindBack (SIG const& f, Tuple<ValTypes> arg)
{ {
RightReplacedArgs params {BuildR(std::move(arg))}; RightReplacedArgs params {BuildR(std::move(arg))};
return func::Apply<ARG_CNT>::template bind<RightReducedFunc> (f, params); return bindArgTuple (f, params);
} }
}; };
@ -611,6 +626,7 @@ namespace func{
{ {
Tuple<PreparedArgTypes> params {BuildPreparedArgs{std::make_tuple (val)}}; Tuple<PreparedArgTypes> params {BuildPreparedArgs{std::make_tuple (val)}};
return func::Apply<ARG_CNT>::template bind<ReducedFunc> (f, params); return func::Apply<ARG_CNT>::template bind<ReducedFunc> (f, params);
// return bindArgTuple (f, params); ///////////////////////////////////////////////////////OOO does not compile when pos > length of ArgList
} }
}; };
@ -622,18 +638,11 @@ namespace func{
using util::unConst; using util::unConst;
template<typename RET, typename ARG>
struct _Sig
{
using Type = typename BuildFunType<RET, ARG>::Sig;
using Applicator = TupleApplicator<Type>;
};
template<typename SIG, typename ARG> template<typename SIG, typename ARG>
struct _Clo struct _Clo
{ {
using Ret = typename _Fun<SIG>::Ret; using Ret = typename _Fun<SIG>::Ret;
using Signature = typename _Sig<Ret,ARG>::Type; using Signature = typename BuildFunType<Ret, ARG>::Sig;
using Type = FunctionClosure<Signature>; using Type = FunctionClosure<Signature>;
}; };

1
src/stage/interact/view-spec-dsl.hpp
View file

@ -208,7 +208,6 @@ namespace interact {
using lib::meta::Split; using lib::meta::Split;
using lib::meta::Tuple; using lib::meta::Tuple;
using lib::meta::TySeq; using lib::meta::TySeq;
using lib::meta::func::_Sig;
using lib::meta::func::PApply; using lib::meta::func::PApply;
typedef typename _Fun<FUN>::Ret Ret; typedef typename _Fun<FUN>::Ret Ret;

21
tests/library/meta/function-closure-test.cpp
View file

@ -84,6 +84,7 @@ namespace test {
using func::Apply; using func::Apply;
using func::TupleApplicator; using func::TupleApplicator;
using func::bindArgTuple;
using func::FunctionClosure; using func::FunctionClosure;
using func::closure; using func::closure;
@ -208,6 +209,10 @@ namespace test {
Tuple<TySeq<int>> tup1 (11); Tuple<TySeq<int>> tup1 (11);
Tuple<TySeq<int,int>> tup2 (11,12); Tuple<TySeq<int,int>> tup2 (11,12);
Tuple<TySeq<int,int,int>> tup3 (11,12,13); Tuple<TySeq<int,int,int>> tup3 (11,12,13);
DUMPVAL (tup0);
DUMPVAL (tup1);
DUMPVAL (tup2);
DUMPVAL (tup3);
typedef function<int()> BoundFun; typedef function<int()> BoundFun;
@ -221,10 +226,10 @@ namespace test {
CHECK (11+12 == functor2() ); CHECK (11+12 == functor2() );
CHECK (11+12+13 == functor3() ); CHECK (11+12+13 == functor3() );
functor0 = TupleApplicator<int()> (tup0).bind (fun0); functor0 = bindArgTuple (fun0, tup0);
functor1 = TupleApplicator<int(int)> (tup1).bind (fun1); functor1 = bindArgTuple (fun1, tup1);
functor2 = TupleApplicator<int(int,int)> (tup2).bind (fun2); functor2 = bindArgTuple (fun2, tup2);
functor3 = TupleApplicator<int(int,int,int)> (tup3).bind (fun3); functor3 = bindArgTuple (fun3, tup3);
CHECK (-1 == functor0() ); CHECK (-1 == functor0() );
CHECK (11 == functor1() ); CHECK (11 == functor1() );
@ -258,10 +263,10 @@ namespace test {
CHECK (11+12 == functor2() ); CHECK (11+12 == functor2() );
CHECK (11+12+13 == functor3() ); CHECK (11+12+13 == functor3() );
functor0 = TupleApplicator<int()> (tup0).bind (unbound_functor0); functor0 = bindArgTuple (unbound_functor0, tup0);
functor1 = TupleApplicator<int(int)> (tup1).bind (unbound_functor1); functor1 = bindArgTuple (unbound_functor1, tup1);
functor2 = TupleApplicator<int(int,int)> (tup2).bind (unbound_functor2); functor2 = bindArgTuple (unbound_functor2, tup2);
functor3 = TupleApplicator<int(int,int,int)> (tup3).bind (unbound_functor3); functor3 = bindArgTuple (unbound_functor3, tup3);
CHECK (-1 == functor0() ); CHECK (-1 == functor0() );
CHECK (11 == functor1() ); CHECK (11 == functor1() );

131
wiki/thinkPad.ichthyo.mm
View file

@ -164397,6 +164397,137 @@ Since then others have made contributions, see the log for the history.</font></
</node> </node>
</node> </node>
</node> </node>
<node CREATED="1749079273770" ID="ID_579464028" MODIFIED="1749079303130" TEXT="Schritt 2: Bind-to-Arg-Tuple neu implementieren">
<node CREATED="1749079304502" ID="ID_1638673098" MODIFIED="1749079325099" TEXT="rein intuitiv: das k&#xf6;nnte mit der tuple-for-each Technik gehen...">
<node CREATED="1749079326999" ID="ID_34944630" MODIFIED="1749079363110" TEXT="also siehe forEach (tup, fun) ini tuple-helper.hpp"/>
<node CREATED="1749079368228" ID="ID_1090818949" MODIFIED="1749081564861" TEXT="und zwar mit diesem upack-Trick nach David Vandervoorde">
<arrowlink COLOR="#5d38bc" DESTINATION="ID_667556429" ENDARROW="Default" ENDINCLINATION="23;-31;" ID="Arrow_ID_1911198692" STARTARROW="None" STARTINCLINATION="-163;8;"/>
</node>
<node CREATED="1749079417426" ID="ID_25131995" MODIFIED="1749079495704" TEXT="wende std::apply auf ein Lambda an &#x27f6; bekommt Tupel-Elemente als Argument-Pack">
<icon BUILTIN="idea"/>
</node>
<node CREATED="1749080688030" ID="ID_162973867" MODIFIED="1749080711048" TEXT="scheint zu gehen .... zumindest wird&apos;s schon mal vom Compiler akzeptiert"/>
<node CREATED="1749080712258" ID="ID_1500605099" MODIFIED="1749080733204" TEXT="und wir haben nur volles forwarding f&#xfc;r diesen Aufruf &#x27f6; Kopie im Binder"/>
</node>
<node CREATED="1749081475903" ID="ID_605063967" MODIFIED="1749081505836" TEXT="Zwischenschritt">
<node CREATED="1749081506641" ID="ID_667556429" MODIFIED="1749081559124" TEXT="neue Hilfsfunktion bindArgTuple">
<linktarget COLOR="#5d38bc" DESTINATION="ID_667556429" ENDARROW="Default" ENDINCLINATION="23;-31;" ID="Arrow_ID_1911198692" SOURCE="ID_1090818949" STARTARROW="None" STARTINCLINATION="-163;8;"/>
</node>
<node CREATED="1749081571461" ID="ID_1222760176" MODIFIED="1749081586647" TEXT="dann Verwendungen des TupleApplicators eliminieren"/>
<node CREATED="1749082302350" ID="ID_1914498797" MODIFIED="1749082308154" TEXT="BindToArgument umstellen">
<node CREATED="1749082310090" ID="ID_618843730" MODIFIED="1749082348031" TEXT="Problem: out-of-bounds Index jetzt anders behandelt">
<node CREATED="1749082386028" ID="ID_1571223641" MODIFIED="1749082388299" TEXT="bisher...">
<node CREATED="1749082348881" ID="ID_1539878278" MODIFIED="1749082385036" TEXT="es wurde Apply&lt;ARG_CNT&gt; ausgew&#xe4;hlt"/>
<node CREATED="1749082393371" ID="ID_1673961372" MODIFIED="1749082436871" TEXT="das hat hinten &#xfc;bersch&#xfc;ssige Tupel-Elemente stillschweigend ignoriert">
<richcontent TYPE="NOTE"><html>
<head>
</head>
<body>
<p>
da es auf std::get&lt;i&gt; mit frest verdrahtetem Index aufsetzt
</p>
</body>
</html>
</richcontent>
</node>
</node>
<node CREATED="1749082438789" ID="ID_477817163" MODIFIED="1749082442014" TEXT="nun...">
<node CREATED="1749082442742" ID="ID_71863154" MODIFIED="1749082453887" TEXT="ein zu gro&#xdf; konstruiertes Binder-Tupel wird durchgereicht"/>
<node CREATED="1749082454586" ID="ID_1932110866" MODIFIED="1749082461397" TEXT="std::apply ist wirklich voll generisch"/>
<node CREATED="1749082466958" ID="ID_1265074650" MODIFIED="1749082473555" TEXT="&#x27f9; Compilation-Failure im Binder"/>
</node>
</node>
<node BACKGROUND_COLOR="#f0d5c5" COLOR="#990033" CREATED="1749082478231" ID="ID_1161415270" MODIFIED="1749082494638" TEXT="kann man das bestehende Verhalten erhalten?">
<icon BUILTIN="help"/>
<node CREATED="1749082495532" ID="ID_367606531" MODIFIED="1749082502619" TEXT="wei&#xdf; zwar nicht ob das sinnvoll ist...?"/>
<node CREATED="1749082503424" ID="ID_1896561211" MODIFIED="1749082514629" TEXT="aber es gibt einen Test und es ist so dokumentiert"/>
<node CREATED="1749082714136" ID="ID_1965208394" MODIFIED="1749082734615" TEXT="also &#x27f9; wie kommt die L&#xe4;nge des Binder-Tuples in BindToArg zustande?">
<node CREATED="1749085756772" ID="ID_1774712935" MODIFIED="1749085768340" TEXT="es wird aus drei Teilen zusammengesetzt"/>
<node CREATED="1749085769610" ID="ID_1876115458" MODIFIED="1749085780773" TEXT="und Pr&#xe4;fix/Suffix beruhen auf der angegebenen pos"/>
<node CREATED="1749085786524" ID="ID_1747871175" MODIFIED="1749085803306" TEXT="Zugriff vewendet die Splice-Metafunktion">
<node CREATED="1749086105021" ID="ID_242475174" MODIFIED="1749086116894" TEXT="Splice war explizit f&#xfc;r diesen Zweck geschaffen worden">
<icon BUILTIN="info"/>
<node CREATED="1749086171316" ID="ID_289035698" MODIFIED="1749086179374" TEXT="der Name ist etwas irref&#xfc;hrend"/>
<node CREATED="1749086180059" ID="ID_1000117906" MODIFIED="1749086190840" TEXT="es ist mehr wie ein &#xbb;slide edit&#xab;"/>
<node CREATED="1749086192917" ID="ID_51185866" MODIFIED="1749086202659" TEXT="gepr&#xfc;ft: es gibt nur diese eine Verwendung"/>
</node>
<node BACKGROUND_COLOR="#fafe99" COLOR="#fa002a" CREATED="1749086082424" ID="ID_792762505" MODIFIED="1749086090303" TEXT="Fehler in List-Splice">
<icon BUILTIN="broken-line"/>
<node CREATED="1749086093678" ID="ID_1935542921" MODIFIED="1749086103057" TEXT="dank umgeschriebenen Test jetzt klar zu sehen">
<node CREATED="1749086219612" ID="ID_1085792366" MODIFIED="1749086248922" TEXT="OLi : -&lt;9&gt;-&lt;8&gt;-"/>
<node CREATED="1749086269399" ID="ID_878268645" MODIFIED="1749086278084" TEXT="List1: -&lt;1&gt;-&lt;2&gt;-&lt;3&gt;-"/>
<node CREATED="1749086340477" ID="ID_1317717416" MODIFIED="1749086342945" TEXT="Fall-1">
<node CREATED="1749086293428" ID="ID_294374445" MODIFIED="1749086474248" TEXT="Splice&lt;List1, OLi&gt;: -&lt;9&gt;-&lt;8&gt;-&lt;3&gt;-">
<icon BUILTIN="button_ok"/>
</node>
<node CREATED="1749086357867" ID="ID_302844078" MODIFIED="1749086474248" TEXT="Splice&lt;List1, OLi2, 0&gt;::Front: &quot;-&quot;">
<icon BUILTIN="button_ok"/>
</node>
<node BACKGROUND_COLOR="#e0ceaa" COLOR="#690f14" CREATED="1749086380050" ID="ID_464757347" MODIFIED="1749086487758" TEXT="Splice&lt;List1, OLi2, 0&gt;::Back: -&lt;2&gt;-&lt;3&gt;-">
<icon BUILTIN="broken-line"/>
</node>
</node>
<node CREATED="1749086394605" ID="ID_23168968" MODIFIED="1749086396476" TEXT="Fall-2">
<node CREATED="1749086407860" ID="ID_1388390572" MODIFIED="1749086474248" TEXT="Splice&lt;List1, OLi, 1&gt;: -&lt;1&gt;-&lt;9&gt;-&lt;8&gt;-">
<icon BUILTIN="button_ok"/>
</node>
<node CREATED="1749086430949" ID="ID_1849113809" MODIFIED="1749086474248" TEXT="Splice&lt;List1, OLi2, 1&gt;::Front: -&lt;1&gt;-">
<icon BUILTIN="button_ok"/>
</node>
<node BACKGROUND_COLOR="#e0ceaa" COLOR="#690f14" CREATED="1749086451494" ID="ID_1435991702" MODIFIED="1749086487758" TEXT="Splice&lt;List1, OLi2, 1&gt;::Back: -&lt;3&gt;-">
<icon BUILTIN="broken-line"/>
</node>
</node>
</node>
<node BACKGROUND_COLOR="#e0ceaa" COLOR="#bd0711" CREATED="1749086526784" ID="ID_757037322" MODIFIED="1749086594846">
<richcontent TYPE="NODE"><html>
<head>
</head>
<body>
<p style="text-align: center">
d.h.: f&#252;r die Back-Berchnung
</p>
<p style="text-align: center">
wird die L&#228;nge der Overlay-Liste
</p>
<p style="text-align: center">
nicht richtig gerechnet
</p>
<p style="text-align: center">
<font size="2">&#187; off by one &#171;</font>
</p>
</body>
</html>
</richcontent>
<icon BUILTIN="broken-line"/>
<node CREATED="1749089660750" ID="ID_1758217572" MODIFIED="1749089678824" TEXT="sonderbar: dieser Fehler besteht so schon lange....">
<icon BUILTIN="clanbomber"/>
</node>
<node CREATED="1749089681585" ID="ID_1206510313" MODIFIED="1749089694378" TEXT="warum wurde das nie bemerkt?">
<node CREATED="1749089706918" ID="ID_1155480413" MODIFIED="1749089728318" TEXT="Hypothese: man hat immer nur das close-last wirklich getestet"/>
<node COLOR="#5b280f" CREATED="1749090006670" ID="ID_844297972" MODIFIED="1749090022859" TEXT="das stimmt nicht! function-composition-test: check_bindToArbitraryParameter">
<icon BUILTIN="button_cancel"/>
</node>
</node>
<node BACKGROUND_COLOR="#fdfdcf" COLOR="#ff0000" CREATED="1749090267058" ID="ID_541383828" MODIFIED="1749090428234" TEXT="Fokussierte Untersuchung notwendig!">
<icon BUILTIN="yes"/>
</node>
</node>
</node>
</node>
</node>
</node>
</node>
<node COLOR="#338800" CREATED="1749081592088" ID="ID_1143027952" MODIFIED="1749081623439" TEXT="Tests OK">
<icon BUILTIN="button_ok"/>
<node COLOR="#435e98" CREATED="1749081604439" ID="ID_372037050" MODIFIED="1749081621876" TEXT="FunctionClosure_test"/>
<node COLOR="#435e98" CREATED="1749081613141" ID="ID_126616986" MODIFIED="1749081621876" TEXT="FunctionComposition_test"/>
<node COLOR="#435e98" CREATED="1749081619255" ID="ID_945095728" MODIFIED="1749081621876" TEXT="TupleClosure_test"/>
</node>
</node>
</node>
</node> </node>
</node> </node>
</node> </node>