Type Variations¶
Type variations may be used to represent differences in representation between different consumers. For example, an engine might support dictionary encoding for a string, or could be using either a row-wise or columnar representation of a struct. All variations of a type are expected to have the same semantics when operated on by functions or other expressions.
All variations except the “system-preferred” variation (a.k.a. [0], see Type Parsing) must be defined using simple extensions. The key properties of these variations are:
| Property | Description |
|---|---|
| Base Type Class | The type class that this variation belongs to. |
| Name | The name used to reference this type. Should be unique within type variations for this parent type within a simple extension. |
| Description | A human description of the purpose of this type variation. |
| Function Behavior | INHERITS or SEPARATE: whether functions that support the system-preferred variation implicitly also support this variation, or whether functions should be resolved independently. For example, if one has the function add(i8,i8) defined and then defines an i8 variation, this determines whether the i8 variation can be bound to the base add operation (inherits) or whether a specialized version of add needs to be defined specifically for this variation (separate). Defaults to inherits. |