The Magnolia Programming Language

Magnolia is a research programming language based on the theory of institutions.

As of May 2022, this repository guides the evolution of Magnolia and hosts the magnoliac compiler.

⚠️ The compiler is still at an experimental stage. Expect bugs, sharp edges, and changing APIs. ⚠️

Getting started

How to install

To install the Magnolia compiler, simply run the following command:

make install

magnoliac will then be installed in the default directory for your cabal binaries. By default, this should be ~/.cabal/bin. Make sure that directory is in your PATH.

How to build Magnolia programs

To build a Magnolia program, use the build command as follows:

magnoliac build <path/to/package.mg> --output-directory <path/to/generated/files>

By default, this command does NOT overwrite files. In order to re-generate previously generated programs in the same output directory, you can explicitly add the --allow-overwrite flag to your command.

Using the REPL

⚠️ The repl feature, while functional, is outdated, and likely on the way to being deprecated. ⚠️

Another option to explore Magnolia source files is to explore them using the repl option instead:

magnoliac repl
mgn> help
Available commands are:
        help: show this help menu
        inspectm: inspect a module
        inspectp: inspect a package
        list: list the loaded packages
        load: load a package
        reload: reload a package

For example, given a file named "example.mg" at the root of the repo, one can load it and inspect its contents like so:

mgn> load example
mgn> inspectp example
SomeSig
SomeConcept
SomeOtherConcept

For developers

How to compile

The compiler has been tested with GHC 8.10.3 and is built using cabal. A very simplistic Makefile is provided, and the following should be sufficient to get going with a development version of the compiler:

make build
# For convenience, you may define an alias for the compiler
alias magnoliac='cabal exec magnoliac --'

How to contribute

Feel free to open issues and pull requests!

Style guide

We roughly follow the same guidelines as specified in the Futhark project. Most importantly:

• lines should (as much as possible) be under 80 characters long;
• we use 2 spaces for indent.