Growl

Growl is my test-bed for writing a statically typed concatenative language.

The upstream repository is located at https://git.rhzm.org/lobo/growl. Repositories in GitHub and, Codeberg are kept mirrored.

It currently features a type system and inference engine based on Robert Kleffner's "A Foundation for Typed Concatenative Languages" thesis.

Executing the interpreter can be done like so:

$ dune exec -- ./exe/main.exe run examples/uncons.grr
([2 3 4] some)

Without any arguments it defaults to reading from standard input.

Building

Install the dependencies first:

$ opam install cmdliner sexplib
$ opam install alcotest # to run tests

Then execute dune build or dune runtest to run the tests.

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While it hasn't been implemented yet, the main thing I want to explore with Growl is what I call "latent execution", a technique that allows for a more flexible syntax while keeping the type system and execution semantics sound by using type information to defer and execute words when their dependencies are satisfied; for instance:

println if (1 + 2 = 3) {"True"} {"False"}

# Should be identical to:
1 2 + 3 = {"True"} {"False"} if println