Represents an equivalent of the Prolog call \+\+Pred. The aim is to determine if Pred succeeds without binding any variables in the call. More...

#include <pred.hpp>

Inheritance diagram for pl_search::NotNot:

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Collaboration diagram for pl_search::NotNot:

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Public Member Functions
	NotNot (Trail *trail, PredPtr pred)
	Create the equivalent of Prolog's \+\+p call.

bool	call () override
	Calls the NotNot predicate.

Public Member Functions inherited from pl_search::Pred
	Pred (Trail *trail)
	Default constructor.

PredPtr	get_continuation ()
	Gets the continuation of the predicate.

virtual void	set_continuation (PredPtr cont)
	Sets the continuation of the predicate.

PredPtr	last_pred ()
	Follows the continuation chain to the last predicate.

virtual void	call_init ()
	Initialize call.

bool	call_continuation ()
	Calls the continuation of the predicate - first call_init and then call.

virtual	~Pred ()=default
	Virtual destructor for proper cleanup.

virtual std::string	get_name ()
	For debugging.

Protected Attributes
PredPtr	pred

Protected Attributes inherited from pl_search::Pred
PredPtr	continuation
	The continuation of the predicate.

Trail *	trail
	Pointer to the trail for managing variable bindings.

Detailed Description

Represents an equivalent of the Prolog call \+\+Pred. The aim is to determine if Pred succeeds without binding any variables in the call.

The NotNot meta-predicate is very similar to the Once predicate except that any variable bindings made by Pred are undone both on failure and success of the Pred call. NotNot is used to determine if Pred would succeed without committing to any variable bindings made by the call to Pred. Note that Pred is a local call - i.e. its continuation is not related to the continuation of the NotNot predicate.

Constructor & Destructor Documentation

◆ NotNot()

pl_search::NotNot::NotNot	(	Trail *	trail,
		PredPtr	pred
	)

inline

Create the equivalent of Prolog's \+\+p call.

Parameters

trail	Pointer to the trail.
pred	is the predicate called within NotNot.

Member Function Documentation

◆ call()

bool pl_search::NotNot::call ( )

overridevirtual

Calls the NotNot predicate.

Returns: True if the predicate succeeds and the continuation succeeds, false otherwise, removing any choice points and variable bindings made by the predicate.

NotNot is very similar to Once except that any variable bindings made by pred are undone both on failure and success of the pred call.

Reimplemented from pl_search::Pred.

Member Data Documentation

◆ pred

PredPtr pl_search::NotNot::pred

protected

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

include/pl_search/pred.hpp
src/pred.cpp

Public Member Functions