session and process are the same thing, but aren't, and this causes pain

[deepfire]

Witness haskell-process-start:

    (haskell-session-set-process session process)
    (haskell-process-set-session process session)

..this says everything. The objects are the same thing, and the question is what to do about it.

I propose we cease this schizophrenia, recognize this fact and merge them into one single entity -- let's provisionally call it proc, for the lack of a better name.

@gracjan, what do you think?

[geraldus]

I think it is good idea.

[gracjan]

Good idea. Note that historically there were supposed to be two processes per session one used while the other was reloading. I think we should be conceptually open to the idea that we have a foreground interactive process and a background process that is ghc-mod or ide-backend based. Someday. Right now it is good to unify session and process.

[gracjan]

@deepfire: Do you have a good plan how to unify session and process? That is a lot of code. Can you list tasks that would lead to the unification?

[deepfire]

I don't except one vague idea that -- since session has a longer lifetime than process, the latter should be merged into the former.

This can be done in two steps:

1. Trivial substitution -- maximum mechanical text transformation, so as not to break anything
2. Perform sweeping simplifications

[deepfire]

Progress made in #808.

[gracjan]

In the light of intero I think we should skip all major overhauls in interactive mode. Intero itself is such an overhaul.