[plum] Tutorial: Arbitrary Nesting

All plum data store types and transforms conform to a plug and play interface. This facilitates using any store type or transform in a place where a type or transform embeds other types or transforms such as (but not limited to) the ArrayX transform or Structure data store types. The plug and play architecture facilitates practically unlimited nesting levels and combinations. The following example demonstrates four levels of nesting. Notice in the Access column of the dump that the indentation increases for every level to help visualize the nesting.

>>> from plum.array import ArrayX
>>> from plum.int import IntX
>>> from plum.structure import Structure, member
>>> from plum.utilities import unpack_and_dump
>>>
>>> uint8 = IntX(byteorder='little', nbytes=1, signed=False)
>>> inner_array = ArrayX(fmt=uint8, dims=(3,))
>>>
>>> class MyStruct(Structure):
...     count: int = member(fmt=uint8)
...     array: list = member(fmt=inner_array)
...
>>> outer_array = ArrayX(fmt=MyStruct, dims=(2,))
>>>
>>> x, dump = unpack_and_dump(outer_array, bytes(range(8)))
>>> print(dump)
+--------+---------+-------+-------+----------------------+
| Offset | Access  | Value | Bytes | Format               |
+--------+---------+-------+-------+----------------------+
|        |         |       |       | List[MyStruct]       |
|        | [0]     |       |       | MyStruct (Structure) |
| 0      |   count | 0     | 00    | uint8                |
|        |   array |       |       | List[int]            |
| 1      |     [0] | 1     | 01    | uint8                |
| 2      |     [1] | 2     | 02    | uint8                |
| 3      |     [2] | 3     | 03    | uint8                |
|        | [1]     |       |       | MyStruct (Structure) |
| 4      |   count | 4     | 04    | uint8                |
|        |   array |       |       | List[int]            |
| 5      |     [0] | 5     | 05    | uint8                |
| 6      |     [1] | 6     | 06    | uint8                |
| 7      |     [2] | 7     | 07    | uint8                |
+--------+---------+-------+-------+----------------------+
>>>
>>> x[1].array[1]
6