func newSargableUnary(pred expression.UnaryFunction) *sargableUnary {
rv := &sargableUnary{}
rv.test = func(expr2 expression.Expression) (bool, error) {
return SubsetOf(pred, expr2) ||
pred.Operand().EquivalentTo(expr2), nil
}
return rv
}
func newSargValued(pred expression.UnaryFunction) *sargValued {
rv := &sargValued{}
rv.sarger = func(expr2 expression.Expression) (plan.Spans, error) {
if SubsetOf(pred, expr2) {
return _SELF_SPANS, nil
}
if pred.Operand().EquivalentTo(expr2) {
return _VALUED_SPANS, nil
}
return nil, nil
}
return rv
}