func LessThan(expr1, expr2 expression.Expression) bool {
value1 := expr1.Value()
value2 := expr2.Value()
return value1 != nil && value2 != nil &&
value1.Collate(value2) < 0
}
func SubsetOf(expr1, expr2 expression.Expression) bool {
v2 := expr2.Value()
if v2 != nil {
return v2.Truth()
}
s := newSubset(expr1)
result, _ := expr2.Accept(s)
return result.(bool)
}
/*
The function NewExecute returns a pointer to the Execute
struct with the input argument expressions value as a field.
*/
func NewExecute(prepared expression.Expression) *Execute {
var preparedValue value.Value
switch prepared := prepared.(type) {
case *expression.Identifier:
preparedValue = value.NewValue(prepared.Alias())
default:
preparedValue = prepared.Value()
}
rv := &Execute{
prepared: preparedValue,
}
rv.stmt = rv
return rv
}