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TreeExplorer: simple implementation based on eager pulling and an Invariant

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lazy pulling would require us to store an additional bool
(the way the FilterIterator from itertools does)
This commit is contained in:
Fischlurch 2017-12-07 01:37:03 +01:00
parent 2eacde7f2c
commit e9e7004a2e
2 changed files with 30 additions and 14 deletions
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27
src/lib/iter-tree-explorer.hpp
View file

@ -663,7 +663,7 @@ namespace lib {
using FilterPredicate = typename _Traits::Functor;
FilterPredicate trafo_;
FilterPredicate predicate_;
public:
@ -672,15 +672,18 @@ namespace lib {
Filter (SRC&& dataSrc, FUN&& filterFun)
: SRC{move (dataSrc)}
, trafo_{forward<FUN> (filterFun)}
{ }
, predicate_{forward<FUN> (filterFun)}
{
pullFilter(); // initially pull to establish the invariant
}
/** refresh state when other layers manipulate the source sequence */
/** refresh state when other layers manipulate the source sequence.
* @note possibly pulls to re-establish the invariant */
void
expandChildren()
{
//////////////////////TODO trigger re-evaluation here...
pullFilter();
SRC::expandChildren();
}
@ -689,19 +692,20 @@ namespace lib {
bool
checkPoint() const
{
return false; //////////////TODO filter and pull here...
return bool(srcIter());
}
typename SRC::reference
yield() const
{
return *(*this);
return *srcIter();
}
void
iterNext()
{
++ srcIter();
pullFilter();
}
private:
@ -711,11 +715,14 @@ namespace lib {
return unConst(*this);
}
bool
/** @note establishes the invariant:
* whatever the source yields as current element,
* has already been approved by our predicate */
void
pullFilter ()
{
////////////////////////TODO while-not-filter iter
return false; //////////TODO return true if any result??
while (srcIter() and not predicate_(srcIter()))
++srcIter();
}
};
}

17
wiki/thinkPad.ichthyo.mm
View file

@ -5706,12 +5706,21 @@
<node CREATED="1511837345226" ID="ID_991593174" MODIFIED="1511837351797" TEXT="bestehende Funktor-Argument-Traits"/>
</node>
<node CREATED="1512523892775" ID="ID_673112014" MODIFIED="1512523896362" TEXT="Knackpunkte">
<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1512523897422" ID="ID_1007287631" MODIFIED="1512523916092" TEXT="pullFilter">
<icon BUILTIN="flag-yellow"/>
<node COLOR="#338800" CREATED="1512523897422" ID="ID_1007287631" MODIFIED="1512606862773" TEXT="pullFilter">
<icon BUILTIN="button_ok"/>
</node>
<node CREATED="1512523905005" ID="ID_1286045611" MODIFIED="1512523921543" TEXT="wie &quot;ausgewertet&quot; merken?">
<icon BUILTIN="help"/>
</node>
<node CREATED="1512606810364" ID="ID_1956085441" MODIFIED="1512606857354" STYLE="fork" TEXT="garnicht">
<icon BUILTIN="yes"/>
<node CREATED="1512606816571" ID="ID_1603234787" MODIFIED="1512606853200" TEXT="mit INVARIANTE arbeiten">
<icon BUILTIN="idea"/>
</node>
<node CREATED="1512606823682" ID="ID_1935971404" MODIFIED="1512606853200" TEXT="erfordert vorauseilendes Pullen">
<icon BUILTIN="messagebox_warning"/>
</node>
</node>
</node>
</node>
<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1512363846804" ID="ID_1346062807" MODIFIED="1512363878326" TEXT="auto-expand">
@ -6287,8 +6296,8 @@
</node>
<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1511836579562" ID="ID_1718741335" MODIFIED="1512523829719" TEXT="verify_FilterIterator();">
<icon BUILTIN="pencil"/>
<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1512523719350" ID="ID_351021178" MODIFIED="1512523742972" TEXT="einfaches Pr&#xe4;dikat">
<icon BUILTIN="flag-yellow"/>
<node COLOR="#338800" CREATED="1512523719350" ID="ID_351021178" MODIFIED="1512606882124" TEXT="einfaches Pr&#xe4;dikat">
<icon BUILTIN="button_ok"/>
</node>
<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1512523726885" ID="ID_282579718" MODIFIED="1512523741403" TEXT="konsumieren bis leer">
<icon BUILTIN="flag-yellow"/>