ubc.cs.JLog.Builtins.Goals
Class jCallGoal

java.lang.Object
  ubc.cs.JLog.Foundation.jGoal
      ubc.cs.JLog.Builtins.Goals.jCallGoal

All Implemented Interfaces:

iName, iNameArity

Direct Known Subclasses:

jCallNGoal, jTimeGoal

public class jCallGoal
extends jGoal

Field Summary

protected jTerm	callee
protected jGoal	end_goal
protected jUnifiedVector	unified

Fields inherited from class ubc.cs.JLog.Foundation.jGoal

next

Constructor Summary

jCallGoal(jTerm c)

Method Summary

int	getArity() Returns the arity of this instance.
String	getName() Returns the name of this instance.
protected void	internal_remove(iGoalStack goals) Make a rule on the proved stack clean up children on the goal stack.
void	internal_restore(iGoalStack goals) Combines internal_remove with a full restart and resoration of any previous variable state.
boolean	prove(iGoalStack goals, iGoalStack proved) Attempt to prove the goal represented by this jGoal.
boolean	retry(iGoalStack goals, iGoalStack proved) Attempt to prove the goal represented by this jGoal.
void	setEndGoal(jGoal goal)
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

callee

protected jTerm callee

unified

protected jUnifiedVector unified

end_goal

protected jGoal end_goal

Constructor Detail

jCallGoal

public jCallGoal(jTerm c)

Method Detail

setEndGoal

public final void setEndGoal(jGoal goal)

prove

public boolean prove(iGoalStack goals,
                     iGoalStack proved)

Description copied from class: jGoal

Attempt to prove the goal represented by this jGoal. Goal must not be on either stack to prove (pop off goals stack before prove call). Goal must place itself on the appropriate stack before returning. proved stack if 'proved', goals stack otherwise. Since proved doesn't pop the stack we don't need a try/catch block. Must be called at least once before calling retry.

Specified by:

prove in class jGoal

Parameters:

goals - iGoalStack containing goals yet to be proved.

proved - iGoalStack containing evaluated goals (goals that may already be proved, or awaiting their child goals to be proved).

Returns:

boolean is true if this goal ended up on proved, false otherwise.

retry

public boolean retry(iGoalStack goals,
                     iGoalStack proved)

Description copied from class: jGoal

Attempt to prove the goal represented by this jGoal. Goal must not be on either stack to retry (pop off proved stack before retry call). Goal must place itself on the goal stack, and normally need not pop either stack. Since retry doesn't pop the stack we don't need a try/catch block.

Specified by:

retry in class jGoal

Parameters:

goals - iGoalStack containing goals yet to be proved.

proved - iGoalStack containing evaluated goals (goals that may already be proved, or awaiting their child goals to be proved).

Returns:

boolean is true if the prover should attempt a prove on this goal, false otherwise.

internal_remove

protected final void internal_remove(iGoalStack goals)

Description copied from class: jGoal

Make a rule on the proved stack clean up children on the goal stack. Should be called from within retry, and should rely on retry to adjust the proved stack. this remains on proved stack.

Overrides:

internal_remove in class jGoal

Parameters:

goals - iGoalStack containing goals yet to be proved.

internal_restore

public final void internal_restore(iGoalStack goals)

Description copied from class: jGoal

Combines internal_remove with a full restart and resoration of any previous variable state. May be called by other goals, such as a jCutGoal. this is still located on proved stack.

Overrides:

internal_restore in class jGoal

Parameters:

goals - iGoalStack containing goals yet to be proved.

getName

public String getName()

Description copied from interface: iName

Returns the name of this instance.

Returns:

String containing name of this instance.

getArity

public int getArity()

Description copied from interface: iNameArity

Returns the arity of this instance.

Returns:

int whose value is the arity of this instance.

toString

public String toString()

Overrides:

toString in class Object