@Override
public Expr optimize(final QueryContext qc, final VarScope scp) throws QueryException {
// number of predicates may change in loop
for (int p = 0; p < preds.length; p++) {
final Expr pred = preds[p];
if (pred instanceof CmpG || pred instanceof CmpV) {
final Cmp cmp = (Cmp) pred;
if (cmp.exprs[0].isFunction(Function.POSITION)) {
final Expr e2 = cmp.exprs[1];
final SeqType st2 = e2.seqType();
// position() = last() -> last()
// position() = $n (numeric) -> $n
if (e2.isFunction(Function.LAST) || st2.one() && st2.type.isNumber()) {
if (cmp instanceof CmpG && ((CmpG) cmp).op == OpG.EQ
|| cmp instanceof CmpV && ((CmpV) cmp).op == OpV.EQ) {
qc.compInfo(OPTWRITE, pred);
preds[p] = e2;
}
}
}
} else if (pred instanceof And) {
if (!pred.has(Flag.FCS)) {
// replace AND expression with predicates (don't swap position tests)
qc.compInfo(OPTPRED, pred);
final Expr[] and = ((Arr) pred).exprs;
final int m = and.length - 1;
final ExprList el = new ExprList(preds.length + m);
for (final Expr e : Arrays.asList(preds).subList(0, p)) el.add(e);
for (final Expr a : and) {
// wrap test with boolean() if the result is numeric
el.add(Function.BOOLEAN.get(null, info, a).optimizeEbv(qc, scp));
}
for (final Expr e : Arrays.asList(preds).subList(p + 1, preds.length)) el.add(e);
preds = el.finish();
}
} else if (pred instanceof ANum) {
final ANum it = (ANum) pred;
final long i = it.itr();
if (i == it.dbl()) {
preds[p] = Pos.get(i, info);
} else {
qc.compInfo(OPTREMOVE, this, pred);
return Empty.SEQ;
}
} else if (pred.isValue()) {
if (pred.ebv(qc, info).bool(info)) {
qc.compInfo(OPTREMOVE, this, pred);
preds = Array.delete(preds, p--);
} else {
// handle statically known predicates
qc.compInfo(OPTREMOVE, this, pred);
return Empty.SEQ;
}
}
}
return this;
}
@Override
public Expr copy(final QueryContext ctx, final VarScope scp, final IntObjMap<Var> vs) {
final Expr[] copy = copyAll(ctx, scp, vs, expr);
final int last = copy.length - 1;
final Expr[] args = Arrays.copyOf(copy, last);
final DynFuncCall call = new DynFuncCall(info, sc, updating, copy[last], args);
if (inlinedFrom != null) call.inlinedFrom = inlinedFrom.clone();
return copyType(call);
}
@Override
public Expr optimize(final QueryContext ctx, final VarScope scp) throws QueryException {
final int ar = expr.length - 1;
final Expr f = expr[ar];
final Type t = f.type().type;
if (t instanceof FuncType) {
final FuncType ft = (FuncType) t;
if (ft.args != null && ft.args.length != ar) throw INVARITY.get(info, f, ar);
if (ft.ret != null) type = ft.ret;
}
if (f instanceof XQFunctionExpr) {
// maps can only contain fully evaluated Values, so this is safe
if (allAreValues() && f instanceof Map) return optPre(value(ctx), ctx);
// try to inline the function
if (!(f instanceof FuncItem && comesFrom((FuncItem) f)) && !updating) {
final Expr[] args = Arrays.copyOf(expr, expr.length - 1);
final Expr inl = ((XQFunctionExpr) f).inlineExpr(args, ctx, scp, info);
if (inl != null) return inl;
}
}
return this;
}
@Override
public void checkUp() throws QueryException {
checkNoneUp(Arrays.copyOf(expr, expr.length - 1));
}