@Override
public Expr comp(final QueryContext ctx) throws QueryException {
ts = checkUp(ts, ctx).comp(ctx);
final Expr[] tmp = new Expr[cases.length];
for (int i = 0; i < cases.length; ++i) tmp[i] = cases[i].expr;
checkUp(ctx, tmp);
// static condition: return branch in question
if (ts.isValue()) {
for (final TypeCase c : cases) {
if (c.var.type == null || c.var.type.instance(ts.value(ctx)))
return optPre(c.comp(ctx, (Value) ts).expr, ctx);
}
}
// compile branches
for (final TypeCase c : cases) c.comp(ctx);
// return result if all branches are equal (e.g., empty)
boolean eq = true;
for (int i = 1; i < cases.length; ++i) {
eq &= cases[i - 1].expr.sameAs(cases[i].expr);
}
if (eq) return optPre(null, ctx);
// evaluate return type
type = cases[0].type();
for (int c = 1; c < cases.length; ++c) {
type = type.intersect(cases[c].type());
}
return this;
}
@Override
public Expr compile(final QueryContext qc, final VarScope scp) throws QueryException {
ts = ts.compile(qc, scp);
// static condition: return branch in question
if (ts.isValue()) {
final Value val = ts.value(qc);
for (final TypeCase tc : cases) {
if (tc.matches(val)) return optPre(tc.compile(qc, scp, (Value) ts).expr, qc);
}
}
// compile branches
for (final TypeCase tc : cases) tc.compile(qc, scp);
return optimize(qc, scp);
}
@Override
public Expr comp(final QueryContext ctx) throws QueryException {
for (final Expr p : pred) checkUp(p, ctx);
Expr e = this;
for (int p = 0; p < pred.length; ++p) {
Expr pr = pred[p].comp(ctx).compEbv(ctx);
pr = Pos.get(CmpV.Op.EQ, pr, pr, input);
if (pr.value()) {
if (!pr.ebv(ctx, input).bool(input)) {
ctx.compInfo(OPTREMOVE, desc(), pr);
e = Empty.SEQ;
break;
}
ctx.compInfo(OPTREMOVE, desc(), pr);
pred = Array.delete(pred, p--);
} else {
pred[p] = pr;
}
}
return e;
}
