version(Version)

Include version Version of File, where Version is a gitty commit of the file. This is the same as :- include(Version)., but more explicit.

If the same file is included at two places it is included at most once. Additionally

• If neither is versioned the most recent version is included.
• If two versions resolve to the same content hash, this is included.
• If a specific version is included, subsequent unspecified includes are ignored. A subsequent incompatibly versioned include results in an error.

The envisioned model is that we can specify which version is, possibly indirectly, included by using directives like this:

:- include(File, [version(Hash)]).