A Unison project is a Unison codebase concept that represents a library, application, or other code package that can be shared, collaborated on, and versioned. You'll create and manipulate projects with a few simple UCM commands and can view your projects on Unison Share.
One Unison codebase often houses multiple libraries, applications, works in progress, and prototypes with varying needs for sharing and structure. Given that Unison code isn't stored in files that can be grouped into git repositories or other conventional collaboration mechanisms, we need an additional codebase abstraction for a packageable unit of code. This is where Unison projects come in. Namespaces are for organizing your source code into a logical tree, whereas projects power developer workflows that are related to collaboration and dependency management.
🏁 Projects quickstart
Let's walk through a quick example of how to navigate a Unison codebase with projects. We'll create a new project, add a project library dependency, create and merge a branch in our project, and push it to Unison Share.
Unison projects formalize many of the conventions you may be familiar with if you've been creating top-level namespaces for your libraries. Projects will live at the root of your codebase and dependencies will still be stored in a lib directory for the project.
Let's create a new project called helloProjects now:
scratch/main> project.create helloProjects
🎉 I've created the project helloProjects.
I'll now fetch the latest version of the base Unison library...
helloProjects/main>In the UCM, your console prompt will be updated to indicate that you're in the helloProjects project; the segment prefixed by a slash, /main, is a branch of the project. Branches are a new feature to Unison projects that allow for concurrent work streams, long-lived feature work, PR's, and more.
Let's create a new branch instead of working on main directly.
helloProjects/main> branch myNewBranch
Done. I've created the myNewBranch branch based off of main
Tip: Use `merge /myNewBranch /main` to merge your work back
into the main branch.branch creates a new branch of the project from the current branch. In this case myNewBranch is a copy of main and contains all the same code and history. Take a look around at the branches of the current project with the branches command and we should see both main and myNewBranch.
helloProjects/myNewBranch> branches
Branch Remote branch
1. main
2. myNewBranchUpon creating a new project, the UCM installs the base standard library as a dependency in the lib namespace for you. The UCM looks for project dependencies in a lib namespace located at the root of the project. Let's add another dependency on the cloud project with the lib.install command.
If you're ever wondering what the command looks like to download a given project, the Unison Share UI shows you the latest download command when you navigate to the project's home page.
helloProjects/myNewBranch> lib.install @unison/cloudThis will install the given latest version of the cloud project into the lib namespace of the current project.
When we're within a project, the existing UCM commands for navigating and viewing namespaces work as before. Let's take a look at the cloud project we just pulled in.
helloProjects/myNewBranch> ls lib.unison_cloud_15_1_0
1. AccessToken (type)
2. AccessToken/ (2 terms)
3. CHANGELOG (base.Doc)
4. CHANGELOG/ (1 term)Open up a scratch.u file in a text editor window and add the following Unison code to it. Save the file when you're ready to add it to the codebase.
README = {{
# Hello Projects
This is a simple Unison project.
}}
helloWorld : '{IO, Exception} ()
helloWorld = do
printLine ("Hello " ++ "yourName")Use the add command in the UCM so the helloWorld function will be present in myNewBranch. In Unison, we don't have specific named "commits", just additions and updates to the codebase state.
We'll merge this branch back into the main branch next.
helloProjects/myNewBranch> add
⍟ I've added these definitions:
README : Doc
helloWorld : '{IO, Exception} ()merge takes two arguments, the source and the destination, respectively. We can indicate that we are merging a branch into another branch by prefixing the branch name with a slash.
helloProjects/myNewBranch> merge /myNewBranch /main
Here's what's changed in helloProjects/main after the merge:
Added definitions:
1. README : Doc
2. helloWorld : '{IO, Exception} ()
Tip: You can use `todo` to see if this generated any work to
do in this namespace and `test` to run the tests. Or you
can use `undo` or `reflog` to undo the results of this
merge.Switch back to the main branch with the switch command, and optionally delete your old feature branch. Now that we've merged our changes into the main branch, we can push our project to Unison Share.
helloProjects/myNewBranch> switch main
helloProjects/main> delete.branch myNewBranchFirst log into Unison Share with the auth.login command. Once logged in, we'll use the push command to do this. Pushing a project to Unison Share will automatically create a remote mapping between the local branch and the remote branch.
helloProjects/main> pushHead to the Unison Share url displayed by the UCM to view your project. You'll see that the main branch is hosted there and the project's welcome page includes your README.
Finally, view a list of your projects with the projects command. You can always get back to your project with the switch command. switch helloProjects will take you back to the last branch you were working on.
helloProjects/main> projects
1. anotherHypotheticalProject
helloProjects/main> switch anotherHypotheticalProjectHooray! You have just created what we hope will be the first of many new Unison projects! Happy coding! 😎
More about projects in Unison
🌟 Full list of common workflows for projects