(Audience: repl client authors)
Once you have a connection to a REPL, you send the content of the resource file unrepl/blob.clj to it (the file is not present in the repository but should be present in the artifact, it's generated by clj -m unrepl.make-blob).
Either you get [:unrepl.upgrade/failed] or [:unrepl/hello ...] on the repl output. Upon failure you are back in the repl you started from.
Each use of the blob creates gensymed namespaces.
You can customize the blob: enter clj -m unrepl.make-blob -o <target-file> -a <session actions map>. Where the session actions map can be either a string or a .edn file. For example:
# As a string
$> clj -m unrepl.make-blob -o foo-blob.clj -a '{:my.own/action (foo/bar #unrepl/param :baz)}'
# As a file
$> clj -m unrepl.make-blob -o foo-blob.clj -a custom-actions.edn
If a custom action has a qualified symbol as the first element (function symbol) for its topmost form, this qualified symbol's namespace will automatically be required on the first use of the action.
Shading of the blob may be optionally turned of with the --noshade option.