ExtensibleFilterIter< IT > Class Template Reference

#include "lib/itertools.hpp"

Description

template<class IT>
class lib::ExtensibleFilterIter< IT >

Additional capabilities for FilterIter, allowing to extend the filter condition underway.

This wrapper enables remoulding of the filer functor while in the middle of iteration. When the filter is modified, current head of iteration gets re-evaluated and possible fast-forwarded to the next element satisfying the now extended filter condition.

Note

changing the condition modifies a given iterator in place. Superficially this might look as if the storage remains the same, but in fact we're adding a lambda closure, which the runtime usually allocates on the heap, holding the previous functor and a second functor for the added clause.

Warning

the addition of disjunctive and negated clauses might actually weaken the filter condition. Yet still there is no reset of the source iterator, i.e. we don't re-evaluate from start, but just from current head. Which means we might miss elements in the already consumed part of the source sequence, which theoretically would pass the now altered filter condition.

See also

IterTools_test::verify_filterExtension

Definition at line 419 of file itertools.hpp.

Public Member Functions
template<typename PRED >
	ExtensibleFilterIter (IT &&src, PRED initialFilterPredicate)
Public Member Functions inherited from FilterIter< IT >
template<typename PRED >
	FilterIter (IT const &src, PRED filterPredicate)
template<typename PRED >
	FilterIter (IT &&src, PRED filterPredicate)
Public Member Functions inherited from IterTool< FilterCore< IT > >
	IterTool (FilterCore< IT > &&setup)
bool	empty () const
bool	isValid () const
	operator bool () const
reference	operator* () const
IterTool &	operator++ ()
pointer	operator-> () const

Private Types
using	_Filter = FilterCore< IT >
using	Val = typename _Filter::Val

Private Member Functions
void	reEvaluate ()

Additional Inherited Members
Public Types inherited from IterTool< FilterCore< IT > >
typedef FilterCore< IT > ::pointer	pointer
typedef FilterCore< IT > ::reference	reference
typedef FilterCore< IT > ::value_type	value_type
Static Public Member Functions inherited from FilterIter< IT >
static bool	acceptAll (typename _Filter::Val)
Protected Member Functions inherited from IterTool< FilterCore< IT > >
void	_maybe_throw () const
bool	hasData () const
bool	iterate ()
Protected Attributes inherited from IterTool< FilterCore< IT > >
FilterCore< IT >	core_

Inheritance diagram for ExtensibleFilterIter< IT >:

Collaboration diagram for ExtensibleFilterIter< IT >:

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The documentation for this class was generated from the following file:

• itertools.hpp