CanBeDomainUnit - ObjectVision/GeoDMS GitHub Wiki
Value type CanBeDomainUnit
definition
CanBeDomainUnit is the group of value types that can be used for a domain unit.
The applies to sections of many [operators and functions]] refer to this group, for [arguments that need to be a domain unit or a relation towards a domain unit.
value types
The group consists of the value types marked in the Can Be Domain Unit column of the value type table:
- [uint8]], [[uint16]], [[uint32]], [[uint64]]: unsigned integers, the most commonly used value types for [one-dimensional (table) domains
- int8, int16, int32, int64: signed integers
- [bool]], [[uint2]], [[uint4]]: [sub byte unsigned integers, for domains with a very limited set of elements
- [spoint]], [[wpoint]], [[ipoint]], [[upoint]]: point value types with integer coordinates, used for [two-dimensional (raster) domains
Furthermore the void value type is in this group; it is used as the (implicit) domain unit of a parameter, with exactly one element.
why
A domain unit defines the set of entries of its attributes, so its value type must be countable, with a defined range of values that maps one-to-one to the row (or row and column) numbers of the domain.
Units with a float32, float64, fpoint, dpoint or string value type are not countable and can therefore not be used as domain unit.