@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 Item item(final QueryContext qc, final InputInfo ii) throws QueryException { // compute scoring if (qc.scoring) { double s = 0; boolean f = false; for (final Expr expr : exprs) { final Item it = expr.ebv(qc, info); f |= it.bool(ii); s += it.score(); } return Bln.get(f, Scoring.avg(s, exprs.length)); } // standard evaluation for (final Expr expr : exprs) { if (expr.ebv(qc, info).bool(ii)) return Bln.TRUE; } return Bln.FALSE; }