CppClingo::ProgramBackend Class Reference

Abstract class connecting grounder and solver. More...

#include <backend.hh>

Public Member Functions
virtual	~ProgramBackend ()=default
	Destroy the backend.
void	preamble (unsigned major, unsigned minor, unsigned revision, bool incremental)
	Initialize the backend.
void	end ()
	Finalize the current grounding step.
auto	next_lit () -> prg_lit_t
	Return a fresh (positive) literal.
auto	fact_lit () -> std::optional< prg_lit_t >
	Get a factual literal if one existis.
void	bd_aggr (PrgLitSpan head, WeightedPrgLitSpan body, int32_t bound, bool choice)
	Define a weight constraint.
void	rule (PrgLitSpan head, PrgLitSpan body, bool choice)
	Add a disjunctive or choice rule.
void	show_term (Symbol sym, PrgLitSpan body)
	Show the given symbol if the given condition is true.
void	show_term (Symbol sym, prg_id_t id)
	Associate the given symbol with an id.
void	show_term (prg_id_t id, PrgLitSpan body)
	Show the symbol with the given id if the given condition is true.
void	show_atom (Symbol sym, prg_lit_t lit)
	Show the atom with the given symbol and program literal.
void	edge (prg_id_t u, prg_id_t v, PrgLitSpan body)
	Add an edge for acyclicity checking.
void	heuristic (prg_lit_t atom, int32_t weight, int32_t prio, HeuristicType type, PrgLitSpan body)
	Add a heuristic directive.
void	external (prg_lit_t atom, ExternalType type)
	Declare the given atom as external.
void	project (PrgLitSpan atoms)
	Project the given atoms.
void	assume (PrgLitSpan literals)
	Assume the given literals.
void	minimize (prg_weight_t priority, WeightedPrgLitSpan body)
	Minimize the given weighted literals.

Detailed Description

Abstract class connecting grounder and solver.

The backend is responsible for passing grounded statements to the solver (or other forms of backends).

Member Function Documentation

assume()

void CppClingo::ProgramBackend::assume ( PrgLitSpan  literals )

inline

Assume the given literals.

Parameters

literals

the literals to assume

bd_aggr()

void CppClingo::ProgramBackend::bd_aggr ( PrgLitSpan  head, WeightedPrgLitSpan  body, int32_t  bound, bool  choice  )

inline

Define a weight constraint.

Precondition

Literals in the head must be positive.

Parameters

head	the literal that is derived
body	the weighted body literals
bound	the lower bound of the constraint
choice	whether the rule has a choice head

edge()

void CppClingo::ProgramBackend::edge ( prg_id_t  u, prg_id_t  v, PrgLitSpan  body  )

inline

Add an edge for acyclicity checking.

Parameters

u	the source vertex
v	the target vertex
body	the body of the statement

external()

void CppClingo::ProgramBackend::external ( prg_lit_t  atom, ExternalType  type  )

inline

Declare the given atom as external.

Precondition

The atom must be positive.

Parameters

atom	the atom to declare external
type	the truth value of the atom

fact_lit()

auto CppClingo::ProgramBackend::fact_lit ( ) -> std::optional<prg_lit_t>

inline

Get a factual literal if one existis.

Returns

the literal

heuristic()

void CppClingo::ProgramBackend::heuristic ( prg_lit_t  atom, int32_t  weight, int32_t  prio, HeuristicType  type, PrgLitSpan  body  )

inline

Add a heuristic directive.

Precondition

The atom must be positive.

Parameters

atom	the atom to modify heuristically
weight	the weight of the modification
prio	the priority of the modification
type	the type of the modification
body	the body of the directive.

minimize()

void CppClingo::ProgramBackend::minimize ( prg_weight_t  priority, WeightedPrgLitSpan  body  )

inline

Minimize the given weighted literals.

Parameters

priority	the priority of the literal
body	the weighted literals of the minimize constraint

next_lit()

auto CppClingo::ProgramBackend::next_lit ( ) -> prg_lit_t

inline

Return a fresh (positive) literal.

All literals should be created using this function.

Returns

the fresh literal

preamble()

void CppClingo::ProgramBackend::preamble ( unsigned  major, unsigned  minor, unsigned  revision, bool  incremental  )

inline

Initialize the backend.

Parameters

major	the major version component
minor	the major version component
revision	the major version component
incremental	whether program updates have to be enabled

project()

void CppClingo::ProgramBackend::project ( PrgLitSpan  atoms )

inline

Project the given atoms.

Precondition

The literals atoms must be positive.

Parameters

atoms

the atoms to project

rule()

void CppClingo::ProgramBackend::rule ( PrgLitSpan  head, PrgLitSpan  body, bool  choice  )

inline

Add a disjunctive or choice rule.

Precondition

Literals in the head must be positive.

Parameters

head	the literals forming the head
body	the literals forming the body
choice	whether the rule is a choice or disjunctive rule

show_atom()

void CppClingo::ProgramBackend::show_atom ( Symbol  sym, prg_lit_t  lit  )

inline

Show the atom with the given symbol and program literal.

Precondition

The literal must be positive.

Parameters

sym	the symbol to show
lit	the literal when to show the symbol

show_term() [1/3]

void CppClingo::ProgramBackend::show_term ( prg_id_t  id, PrgLitSpan  body  )

inline

Show the symbol with the given id if the given condition is true.

Parameters

id	the symbol to show
body	the condition when to show the symbol

show_term() [2/3]

void CppClingo::ProgramBackend::show_term ( Symbol  sym, prg_id_t  id  )

inline

Associate the given symbol with an id.

Note

Raises an exception if the given symbol already has an id.

Parameters

sym	the symbol
id	the id

show_term() [3/3]

void CppClingo::ProgramBackend::show_term ( Symbol  sym, PrgLitSpan  body  )

inline

Show the given symbol if the given condition is true.

Parameters

sym	the symbol to show
body	the condition when to show the symbol

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

• clingo/core/backend.hh