private void narrowByRule(ConstrainedTerm constrainedTerm, Rule rule) {
stopwatch.reset();
stopwatch.start();
constrainedTermResults = new ArrayList<ConstrainedTerm>();
SymbolicConstraint leftHandSideConstraint =
new SymbolicConstraint(constrainedTerm.termContext());
leftHandSideConstraint.addAll(rule.requires());
for (Variable variable : rule.freshVariables()) {
leftHandSideConstraint.add(variable, IntToken.fresh());
}
ConstrainedTerm leftHandSide =
new ConstrainedTerm(
rule.leftHandSide(),
rule.lookups().getSymbolicConstraint(constrainedTerm.termContext()),
leftHandSideConstraint,
constrainedTerm.termContext());
for (SymbolicConstraint constraint : constrainedTerm.unify(leftHandSide)) {
constraint.addAll(rule.ensures());
/* rename rule variables in the constraints */
Map<Variable, Variable> freshSubstitution = constraint.rename(rule.variableSet());
Term result = rule.rightHandSide();
/* rename rule variables in the rule RHS */
result = result.substituteWithBinders(freshSubstitution, constrainedTerm.termContext());
/* apply the constraints substitution on the rule RHS */
result =
result.substituteWithBinders(constraint.substitution(), constrainedTerm.termContext());
/* evaluate pending functions in the rule RHS */
result = result.evaluate(constrainedTerm.termContext());
/* eliminate anonymous variables */
constraint.eliminateAnonymousVariables();
/* compute all results */
constrainedTermResults.add(
new ConstrainedTerm(result, constraint, constrainedTerm.termContext()));
}
stopwatch.stop();
}
// apply rule by matching
private void rewriteByRule(Term term, Rule rule) {
stopwatch.reset();
stopwatch.start();
termResults = new ArrayList<Term>();
TermContext context = TermContext.of(definition);
ConstrainedTerm constrainedTerm = new ConstrainedTerm(term, context);
SymbolicConstraint leftHandSideConstraint = new SymbolicConstraint(context);
leftHandSideConstraint.addAll(rule.requires());
for (Variable variable : rule.freshVariables()) {
leftHandSideConstraint.add(variable, IntToken.fresh());
}
ConstrainedTerm leftHandSide =
new ConstrainedTerm(
rule.leftHandSide(),
rule.lookups().getSymbolicConstraint(context),
leftHandSideConstraint,
context);
for (SymbolicConstraint constraint : constrainedTerm.unify(leftHandSide)) {
if (!constraint.isMatching(leftHandSide)) {
continue;
}
constraint.orientSubstitution(leftHandSide.variableSet());
Term result = rule.rightHandSide();
/* apply the constraints substitution on the rule RHS */
result = result.substituteAndEvaluate(constraint.substitution(), context);
/* compute all results */
termResults.add(result);
}
stopwatch.stop();
}
