Value type - ObjectVision/GeoDMS GitHub Wiki

A Value Type indicates the kind of values that can be stored in parameters and attributes.

• A unit determines a set of comparable values (= domain in the terminology of C.J. Date) and must be related to a specific Value Type.
• A parameter stores one element value, for which the value type is determined by the values unit of the parameter.
• An attribute is implemented as an array of elements of a specific value type. The value type of these elements is determined by the values unit of the attribute. The location of these elements is implicitly determined by their position in the array. The set of valid locations and the type of these location elements is determined by its domain unit.

The engine registers the names of the value types in lower case: bool, uint8, uint32, int32, float32, float64, spoint, dpoint, string, void and their siblings. Names are case insensitive, so Float32 and UInt32 still resolve to the same type, but a spelling that differs only in case from the registered one is reported in the event log as a case mix-up warning. Since GeoDMS 20.19.0 the files the engine itself ships agree with that spelling, so such a warning now points at the configuration; the examples on this wiki are written the way the engine records the names.

unit<float32>      meter             := BaseUnit('m', float32);
parameter<meter>   RealWagonLength   := 22[meter];
parameter<float32> WagonScale        := float32(1.0 / 87.0);
parameter<meter>   ScaledWagonLength := WagonScale * RealWagonLength;