@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 void plan(final Serializer ser) throws IOException {
ser.openElement(this);
for (final TypeCase c : cases) c.plan(ser);
ts.plan(ser);
ser.closeElement();
}
@Override
public Iter iter(final QueryContext qc) throws QueryException {
final Value seq = qc.value(ts);
for (final TypeCase tc : cases) {
final Iter iter = tc.iter(qc, seq);
if (iter != null) return iter;
}
// will never happen
throw Util.notExpected();
}
@Override
public Iter iter(final QueryContext ctx) throws QueryException {
final Value seq = ctx.value(ts);
for (final TypeCase c : cases) {
final Iter iter = c.iter(ctx, seq);
if (iter != null) return iter;
}
// will never happen
throw Util.notexpected();
}
@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 boolean has(final Flag flag) {
for (final TypeCase tc : cases) if (tc.has(flag)) return true;
return ts.has(flag);
}
@Override
public void markTailCalls(final QueryContext qc) {
for (final TypeCase t : cases) t.markTailCalls(qc);
}
@Override
public boolean removable(final Var var) {
for (final TypeCase tc : cases) if (!tc.removable(var)) return false;
return ts.removable(var);
}
@Override
public int count(final Var v) {
int c = ts.count(v);
for (final TypeCase t : cases) c += t.count(v);
return c;
}
@Override
public boolean uses(final Use u) {
if (u == Use.VAR) return true;
for (final TypeCase c : cases) if (c.uses(u)) return true;
return ts.uses(u);
}
@Override
Expr markTailCalls() {
for (final TypeCase t : cases) t.markTailCalls();
return this;
}
@Override
public boolean removable(final Var v) {
for (final TypeCase c : cases) if (!c.removable(v)) return false;
return ts.removable(v);
}
