func newSargEq(expr *expression.Eq) *sargEq {
rv := &sargEq{}
rv.sarg = func(expr2 expression.Expression) (Spans, error) {
if expr.EquivalentTo(expr2) {
return _SELF_SPANS, nil
}
span := &Span{}
if expr.First().EquivalentTo(expr2) {
span.Range.Low = expression.Expressions{expr.Second().Static()}
} else if expr.Second().EquivalentTo(expr2) {
span.Range.Low = expression.Expressions{expr.First().Static()}
}
if len(span.Range.Low) == 0 {
return nil, nil
}
span.Range.High = span.Range.Low
span.Range.Inclusion = datastore.BOTH
return Spans{span}, nil
}
return rv
}
