categoricalAppend

ArrayData[] categoricalAppend(const  ArrayData[]  left,
       const  ArrayData[]  right,  DataType dtype)

@trusted

Appends two categorical chunk lists under the invariant: the dictionaries reconcile once, both sides' codes remap onto the merged dictionary, and the result chunks share it.

Parameters

`left`	the left chunks
`right`	the right chunks
`dtype`	the shared CATEGORICAL dtype

Returns

the appended chunk list (one dictionary shared by all).