mlml is a self-hosted toy compiler for a tiny subset of OCaml.

a detailed description can be found in my blog post (in Japanese): 自作OCamlコンパイラでセルフホストした - molecular coordinates

• basic arithmetic
• variables
• if-then-else
• functions
  • recursion
  • mutual recursion
  • closure
  • currying
• tuples
• variants
• records
• pattern matching
• structual comparison
• primitive types
  • string
  • list
  • bytes
  • array
• formatted output with Printf
• modules
  • definition
  • aliases
  • open
  • dune-like bundler
• self-hosting!
• exceptions
• type checker & type inference

mlml is self-hosted. i.e. mlml can compile itself.

./dev/exec.sh ./dev/self_host.sh

To obtain build artifacts, pass a path to local directory as below. You will see compiled binaries under ./self_host.

mkdir self_host
./dev/exec.sh ./dev/self_host.sh ./self_host

• external definitions are only available for functions
• all modules and paths are statically-resolved
• all custom oeprators are left-associative
• function keyword does not make an expression

If you have docker installed in your system, simply run

./dev/start.sh

to start the development.

You can run tests manually by running the following command:

./dev/exec.sh dune runtest

The code and algorithm in parser and lexer is strongly inspired by ushitora-anqou/aqaml