A statically typed, purely functional, strictly evaluated programming language
that compiles to PHP, JVM and .NET. One .mog source — algebraic
data types, GADT's, pattern matching, type classes, explicit-effect IO — becomes a
.phar, a .jar or a .dll or native executable.
data Shape = Circle Double | Rect Double Double
deriving (Show, Eq)
area :: Shape -> Double
area s = case s of
Circle r -> 3.141592653589793 * r * r
Rect w h -> w * h
main :: IO ()
main = do
putStrLn (show (area (Circle 1.0)))
putStrLn (show (map area [Rect 2.0 3.0, Circle 1.0]))
3.141592653589793
[6.0,3.141592653589793]
Download the distribution for your platform from the releases page and unpack it — it is a complete installation, and running it needs nothing else:
tar -xzf moggi-0.1.0-linux-x86_64.tar.gz # or the .zip on Windows
cd moggi
./bin/moggi versionWrite a program:
-- hello.mog
main = putStrLn "Hello, world!"
./bin/moggi run hello.mog # compile and run it
./bin/moggi run examples/factorial # or run one of the shipped examples
./bin/moggi repl # try expressions interactivelyBuild an artifact you can deploy on its own:
./bin/moggi compile hello.mog # -> hello.phar
php hello.phar
./bin/moggi compile hello.mog --backend jvm # -> hello.jar
java -jar hello.jar
./bin/moggi compile hello.mog --backend dotnet # -> hello.dll
dotnet hello.dllWhich distributions bundle which runtime, and how to use a checkout instead:
Without -o the artifact is named after the entry source file; pass a full file
name to choose your own (-o app.phar, -o app.jar, -o app.dll).
Useful flags: --unpacked keeps the generated tree instead of packaging it,
--native builds a native executable (GraalVM native-image, .NET
PublishAot), and --tokens/--ast/--typed-ast/--ir/--opt-ir dump the
compiler's intermediate stages. --help lists everything.
Read them in order, or pick the question you have.
Full index: docs/README.md, which also lists the compiler's own documentation.
Moggi is alpha: the language and standard library are still being completed, and the three backends are kept byte-for-byte identical by a differential test.
Working on the compiler itself. Moggi the language needs none of this.
The flake pins every toolchain the compiler and test suite use — PHP 8.5, a JDK
21 (GraalVM, so native-image is there too), the .NET 8 SDK — and puts moggi
and runtest on your PATH:
nix developNix is for development, on Linux and macOS. On Windows, or without Nix, the same two commands work directly and use whatever toolchains you have installed:
php moggi.php version # the compiler (what the `moggi` wrapper runs)
php test.php # the test suite (what the `runtest` wrapper runs)php moggi.php --help documents the compiler's commands; php test.php --help
documents the suite's selection and reporting flags.
The editor extension is a separate project with its own release: moggi-lang/moggi-vscode-plugin.
runtest # the default backend (php)
runtest --backend jvm # another backend
runtest --backend all --native # every backend, plus native builds
runtest --group semantics # one group; a path below a group narrows further
runtest --list # what would runThe suite runs the compiler end to end: it compiles cases and compares generated code, IR, diagnostics and program output against goldens, on each backend they declare. docs/development/testing.md describes the layout, what a case looks like, and how goldens are updated.
Parts of this project — code, tests and documentation — were generated by large language models and reviewed by a human.