alice.tuprolog

Class TheoryManager

java.lang.Object

alice.tuprolog.TheoryManager

All Implemented Interfaces:

Serializable

public class TheoryManager
extends Object
implements Serializable

This class defines the Theory Manager who manages the clauses/theory often referred to as the Prolog database. The theory (as a set of clauses) are stored in the ClauseDatabase which in essence is a HashMap grouped by functor/arity.

The TheoryManager functions logically, as prescribed by ISO Standard 7.5.4 section. The effects of assertions and retractions shall not be undone if the program subsequently backtracks over the assert or retract call, as prescribed by ISO Standard 7.7.9 section.

To use the TheoryManager one should primarily use the methods assertA, assertZ, consult, retract, abolish and find.

rewritten by:

Author:

ivar.orstavik@hist.no

See Also:

Theory, Serialized Form

Constructor Summary

Constructors

Constructor and Description
TheoryManager()

Method Summary

Methods

Modifier and Type	Method and Description
boolean	abolish(Struct cl) removing from dbase the first clause with head unifying with clause (m if a free substitution index and t is the first free timestamp)
void	assertA(Struct clause, boolean dyn, String libName, boolean backtrackable) inserting of a clause at the head of the dbase
void	assertZ(Struct clause, boolean dyn, String libName, boolean backtrackable) inserting of a clause at the end of the dbase
void	clear() Clears the clause dbase.
void	consult(Theory theory, boolean dynamicTheory, String libName) Consults a theory.
List	find(Term headt) Returns a family of clauses with functor and arity equals to the functor and arity of the term passed as a parameter
String	getTheory(boolean onlyDynamic) Gets current theory
ClauseInfo	retract(Struct cl) removing from dbase the first clause with head unifying with clause (m if a free substitution index and t is the first free timestamp)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TheoryManager

public TheoryManager()

Method Detail

assertA

public void assertA(Struct clause,
           boolean dyn,
           String libName,
           boolean backtrackable)

inserting of a clause at the head of the dbase

assertZ

public void assertZ(Struct clause,
           boolean dyn,
           String libName,
           boolean backtrackable)

inserting of a clause at the end of the dbase

retract

public ClauseInfo retract(Struct cl)

removing from dbase the first clause with head unifying with clause (m if a free substitution index and t is the first free timestamp)

abolish

public boolean abolish(Struct cl)

removing from dbase the first clause with head unifying with clause (m if a free substitution index and t is the first free timestamp)

find

public List find(Term headt)

Returns a family of clauses with functor and arity equals to the functor and arity of the term passed as a parameter

consult

public void consult(Theory theory,
           boolean dynamicTheory,
           String libName)
             throws InvalidTheoryException

Consults a theory.

Parameters:

theory - theory to add

dynamicTheory - if it is true, then the clauses are marked as dynamic

libName - if it not null, then the clauses are marked to belong to the specificed library

Throws:

InvalidTheoryException

clear

public void clear()

Clears the clause dbase.

getTheory

public String getTheory(boolean onlyDynamic)

Gets current theory

Parameters:

onlyDynamic - if true, fetches only dynamic clauses