MutableFilter< SRC > Class Template Reference

#include "lib/iter-explorer.hpp"

Description

template<class SRC>
class lib::iter_explorer::MutableFilter< SRC >

Special variant of the Filter Decorator to allow for dynamic remoulding. This covers a rather specific use case, where we want to remould or even exchange the Filter predicate in the middle of an ongoing iteration. Such a remoulding can be achieved by binding the existing (opaque) filter predicate into a new combined lambda, thereby capturing it by value. After building, this remoulded version can be assigned to the original filter functor, under the assumption that both are roughly compatible. Moreover, since we wrap the actual lambda into an adapter, allowing for generic lambdas to be used as filter predicates, this setup allows for a lot of leeway regarding the concrete predicates.

Note

whenever the filter is remoulded, the invariant is immediately re-established, possibly forwarding the sequence to the next element approved by the new version of the filter.

Remarks

filter predicates can be specified in a wide variety of forms, and will be adapted automatically. This flexibility also holds for any of the additional clauses provided for remoulding the filter. Especially this means that functors of different kinds can be mixed and combined.

Definition at line 1185 of file iter-explorer.hpp.

Public Member Functions
template<typename FUN >
	MutableFilter (SRC &&dataSrc, FUN &&filterFun)
template<typename COND >
void	andFilter (COND &&conjunctiveClause)
	remould existing predicate to require in addition the given clause to hold
template<typename COND >
void	andNotFilter (COND &&conjunctiveClause)
	remould existing predicate to require in addition the negation of the given clause to hold
void	disableFilter ()
	discard filter predicates and disable any filtering
void	flipFilter ()
	remould existing predicate to negate the meaning of the existing clause
template<typename COND >
void	orFilter (COND &&disjunctiveClause)
	remould existing predicate to require either the old OR the given new clause to hold
template<typename COND >
void	orNotFilter (COND &&disjunctiveClause)
	remould existing predicate to require either the old OR the negation of a new clause to hold
template<typename COND >
void	setNewFilter (COND &&entirelyDifferentPredicate)
	replace the existing predicate with the given, entirely different predicate
Public Member Functions inherited from Filter< SRC >
template<typename FUN >
	Filter (SRC &&dataSrc, FUN &&filterFun)
bool	checkPoint () const
void	expandChildren ()
	refresh state when other layers manipulate the source sequence. More...
void	iterNext ()
SRC::reference	yield () const

Private Types
using	_Filter = Filter< SRC >

Private Member Functions
template<typename COND , class COMB >
void	remouldFilter (COND &&additionalClause, COMB buildCombinedClause)

Additional Inherited Members
Protected Types inherited from Filter< SRC >
using	FilterPredicate = function< bool(SRC &)>
Protected Member Functions inherited from Filter< SRC >
bool	isDisabled () const
void	pullFilter ()
SRC &	srcIter () const
Protected Attributes inherited from Filter< SRC >
FilterPredicate	predicate_

Member Function Documentation

remouldFilter()

void remouldFilter ( COND &&  additionalClause, COMB  buildCombinedClause  )

inlineprivate

boilerplate to remould the filter predicate in-place

Parameters

additionalClause	additional functor object to combine
buildCombinedClause	a generic lambda (important!) to define how exactly the old and the new predicate are to be combined

Note

the actual combination logic is handed in as generic lambda, which essentially is a template class, and this allows to bind to any kind of function objects or lambdas. This combination closure requires a specific setup: when invoked with the existing and the new functor as argument, it needs to build a new likewise generic lambda to perform the combined evaluation.

Warning

the handed-in lambda buildCombinedClause must capture its arguments, the existing functors by value. This is the key piece in the puzzle, since it effectively moves the existing functor into a new heap allocated storage.

Definition at line 1323 of file iter-explorer.hpp.

Inheritance diagram for MutableFilter< SRC >:

Collaboration diagram for MutableFilter< SRC >:

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

• iter-explorer.hpp