bool TheoryArith::isSyntacticRational(const Expr& e, Rational& r)
{
if (e.getKind() == REAL_CONST) {
r = e[0].getRational();
return true;
}
else if (e.isRational()) {
r = e.getRational();
return true;
}
else if (isUMinus(e)) {
if (isSyntacticRational(e[0], r)) {
r = -r;
return true;
}
}
else if (isDivide(e)) {
Rational num;
if (isSyntacticRational(e[0], num)) {
Rational den;
if (isSyntacticRational(e[1], den)) {
if (den != 0) {
r = num / den;
return true;
}
}
}
}
return false;
}
Expr TheoryArith::rewriteToDiff(const Expr& e)
{
Expr tmp = e[0] - e[1];
tmp = canonRec(tmp).getRHS();
switch (tmp.getKind()) {
case RATIONAL_EXPR: {
Rational r = tmp.getRational();
switch (e.getKind()) {
case LT:
if (r < 0) return trueExpr();
else return falseExpr();
case LE:
if (r <= 0) return trueExpr();
else return falseExpr();
case GT:
if (r > 0) return trueExpr();
else return falseExpr();
case GE:
if (r >= 0) return trueExpr();
else return falseExpr();
case EQ:
if (r == 0) return trueExpr();
else return falseExpr();
}
}
case MULT:
DebugAssert(tmp[0].isRational(), "Unexpected term structure from canon");
if (tmp[0].getRational() != -1) return e;
return Expr(e.getOp(), theoryCore()->getTranslator()->zeroVar() - tmp[1], rat(0));
case PLUS: {
DebugAssert(tmp[0].isRational(), "Unexpected term structure from canon");
Rational c = tmp[0].getRational();
Expr x, y;
if (tmp.arity() == 2) {
if (tmp[1].getKind() == MULT) {
x = theoryCore()->getTranslator()->zeroVar();
y = tmp[1];
}
else {
x = tmp[1];
y = rat(-1) * theoryCore()->getTranslator()->zeroVar();
}
}
else if (tmp.arity() == 3) {
if (tmp[1].getKind() == MULT) {
x = tmp[2];
y = tmp[1];
}
else if (tmp[2].getKind() == MULT) {
x = tmp[1];
y = tmp[2];
}
else return e;
}
else return e;
if (x.getKind() == MULT) return e;
DebugAssert(y[0].isRational(), "Unexpected term structure from canon");
if (y[0].getRational() != -1) return e;
return Expr(e.getOp(), x - y[1], getEM()->newRatExpr(-c));
}
default:
return Expr(e.getOp(), tmp - theoryCore()->getTranslator()->zeroVar(), rat(0));
break;
}
return e;
}