Fish shell support

[josephschmitt]

It seems like hermit doesn't work in fish at all. At first I thought it was just the shell hooks, which after looking through the hermit source code didn't seem like it'd be that difficult to add fish support to.

But it seems like none of the activation logic works in fish either. Fish syntax isn't compatible with bash/zsh syntax, so things pretty much just break.

Are there any plans to add support for fish?

[josephschmitt]

I've tried re-directing as much of the bash code as I can to bass and I can get decently far, but it dies at the command using unset. I think that code is generated by the hermit binary, so it would require larger changes to the project.

[alecthomas]

You're correct that Fish does bot work. Unfortunately we don't know Fish at all, but we would love to support it if someone contributed to it.

[alecthomas]

If you'd like to contribute I believe the two things that are needed are:

1. An activation script (bin/activate-hermit.fish) that is installed by Hermit into the environment.
2. Implement the shell.Shell interface.

[zph]

For future hermit<>fish users, I'm experimenting with the following successfully:

• Use direnv
• Add a custom layout hermit directive in your ~/.direnvrc (zph/zph@fe12348)
• Include layout hermit in a .envrc in the root of your project folder

At that point you don't need to activate or deactivate hermit, this is handled by direnv when you enter/leave the project folder.

It uses hermit env to get the full environment needed for hermit and then also cleans up and resets those env vars and PATH afterwards.

[zph]

The benefit of this approach for me is that I don't need to write or maintain a custom fish activation beyond those 5 lines of code.

Thanks for writing hermit and I like the manifest format and simplicity of how it sources and installs binaries.

[alecthomas]

That is super cool, thanks for letting us know. Would you be so kind as to send a PR adding this to the documentation? That would be super helpful.

[marco-m-pix4d]

@zph the commit that you mention above, that adds the custom layout hermit directive, disappeared. Do you still have it somewhere? If you had time to send a PR as suggested by alec it would be even greater :-) In any case, thanks for the idea.