Start a Migration Guide

[FranklandJack]

As part of Unified Runtime we need to provide a migration guide documenting the mapping from the PI plugin API to UR. This should consist of a set of mappings between the various entry points, types enumerations etc. and any divergences in semantics.

i.e. something like

Functions

PI	UR	Differences
piDeviceGetInfo	urDeviceGetInfo	None
...	...	...
...	...	...

Types

PI	UR	Differences
pi_context	ur_context_handle_t	None
...	...	...
...	...	...

Enumerations

PI	UR	Differences
pi_device_info	ur_device_info	(list of removed queries)
...	...	...
...	...	...

The initial proposal is to do this in markdown and have a living document in this repo that can be update as spec changes are made.

[kbenzie]

The handwritten portions of the spec are reStructureText. I feel like this should be part of the spec document rather than separate. That implies writing the migration guide in reStructuredText not Markdown.

[FranklandJack]

Sure reStructureText works just as well for me. @kbenzie Are you happy with the laying this out in tables like above? rst has better support for tables so it's probably a better choice anyway if we are going to go with that.

[kbenzie]

The layout seems fine.