Helper ChoiceArith

Jan Burse, created Jun 16. 2019
package jekpro.frequent.advanced;
import jekpro.model.inter.AbstractChoice;
import jekpro.model.inter.AbstractSpecial;
import jekpro.model.inter.Engine;
import jekpro.model.molec.*;
import jekpro.model.rope.Goal;
import jekpro.model.rope.Intermediate;
import jekpro.reference.arithmetic.EvaluableElem;
import jekpro.reference.arithmetic.SpecialCompare;
import jekpro.reference.arithmetic.SpecialEval;
import jekpro.tools.term.SkelCompound;
import jekpro.tools.term.SkelVar;
/**
* <p>Choice point for module arith built-ins.</p>
* <p/>
* Warranty & Liability
* To the extent permitted by applicable law and unless explicitly
* otherwise agreed upon, XLOG Technologies GmbH makes no warranties
* regarding the provided information. XLOG Technologies GmbH assumes
* no liability that any problems might be solved with the information
* provided by XLOG Technologies GmbH.
* <p/>
* Rights & License
* All industrial property rights regarding the information - copyright
* and patent rights in particular - are the sole property of XLOG
* Technologies GmbH. If the company was not the originator of some
* excerpts, XLOG Technologies GmbH has at least obtained the right to
* reproduce, change and translate the information.
* <p/>
* Reproduction is restricted to the whole unaltered document. Reproduction
* of the information is only allowed for non-commercial uses. Selling,
* giving away or letting of the execution of the library is prohibited.
* The library can be distributed as part of your applications and libraries
* for execution provided this comment remains unchanged.
* <p/>
* Restrictions
* Only to be distributed with programs that add significant and primary
* functionality to the library. Not to be distributed with additional
* software intended to replace any components of the library.
* <p/>
* Trademarks
* Jekejeke is a registered trademark of XLOG Technologies GmbH.
*/
final class ChoiceArith extends AbstractChoice {
private Number cur;
private final Intermediate goalskel;
private final AbstractUndo mark;
private final int id;
/**
* <p>Create pick choice.</p>
*
* @param n The next choice.
* @param m The mark.
* @param i The function code.
*/
ChoiceArith(AbstractChoice n,
Number c, Intermediate r, CallFrame u,
AbstractUndo m, int i) {
super(n, u);
goalskel = r;
cur = c;
mark = m;
id = i;
}
/**
* <p>Logically evaluate a term in a list of goals for an additional time.</p>
* <p>The result is returned via the contskel and contdisplay of the engine.</p>
*
* @param en The engine.
* @return True if the predicate succeeded, otherwise false.
* @throws EngineException Shit happens.
* @throws EngineMessage Shit happens.
*/
public boolean moniNext(Engine en)
throws EngineException, EngineMessage {
/* remove choice point */
en.choices = next;
en.number--;
/* undo bindings */
en.contskel = goalskel;
en.contdisplay = goaldisplay;
en.fault = null;
en.releaseBind(mark);
if (en.fault != null)
throw en.fault;
Intermediate ir = goalskel;
Object t = ir.term;
Display d = goaldisplay.disp;
if ((ir.flags & Goal.MASK_GOAL_NAKE) != 0) {
/* inlined deref */
BindUniv b1;
while (t instanceof SkelVar &&
(b1 = d.bind[((SkelVar) t).id]).display != null) {
t = b1.skel;
d = b1.display;
}
}
Object[] temp = ((SkelCompound) t).args;
switch (id) {
case SpecialArith.SPECIAL_BETWEEN:
Number num2 = SpecialEval.derefAndCastNumber(temp[1], d);
cur = EvaluableElem.add(cur, Integer.valueOf(1));
int res = SpecialCompare.computeCmp(cur, num2);
while (res <= 0) {
if (en.unifyTerm(temp[2], d, cur, Display.DISPLAY_CONST)) {
if (res != 0) {
/* reuse choice point */
en.choices = this;
en.number++;
}
return true;
}
/* undo bindings */
en.fault = null;
en.releaseBind(mark);
if (en.fault != null)
throw en.fault;
cur = EvaluableElem.add(cur, Integer.valueOf(1));
res = SpecialCompare.computeCmp(cur, num2);
}
return false;
case SpecialArith.SPECIAL_ABOVE:
cur = EvaluableElem.add(cur, Integer.valueOf(1));
while (true) {
if (en.unifyTerm(temp[1], d, cur, Display.DISPLAY_CONST)) {
/* reuse choice point */
en.choices = this;
en.number++;
return true;
}
/* undo bindings */
en.fault = null;
en.releaseBind(mark);
if (en.fault != null)
throw en.fault;
cur = EvaluableElem.add(cur, Integer.valueOf(1));
}
default:
throw new IllegalArgumentException(AbstractSpecial.OP_ILLEGAL_SPECIAL);
}
}
/**
* <p>Free data used to logically evaluate a term an additional time.</p>
* <p>The current exception is passed via the engine fault.</p>
* <p>The new current exception is returned via the engine fault.</p>
* <p>The current contskel and contdisplay of the engine is not changed.</p>
*
* @param en The engine.
*/
public void moniCut(Engine en) {
/* remove choice point */
en.choices = next;
en.number--;
}
}

Comments