Are there any implementations of the spineless tagless G-machine other than in GHC?

Question

From Simon Peyton Jones (recent Royal Society member) we read the paper: Implementing lazy functional languages on stock hardware: the Spineless Tagless G-Machine.

Now this paper is part of how they made Haskell a lazy language when they were implementing it, and solved some problems they had at the time.

The only comparable paper seems to be: Compiling Lazy Functional Programs Based on the Spineless Tagless G-machine for the Java Virtual Machine but there doesn't appear to be an implementation available.

One tangentially related is: Compiling Haskell to Java. However in this approach they leave the implementation of the Spineless Tagless G-Machine in GHC and just read the output.

My question is: Are there any implementations of the spineless tagless G-machine other than in GHC?

Answer 1

I used this Google search:

"spineless tagless g-machine" site:github.com

and found 2 repos that (try?) to implement the STG in non-Haskell languages:

PHP: lechimp-p/php-stg

RPython ("restricted" subset of Python developed for Pypy): cgswords/laurens

Answer 2

Here is a good one with nice visualisations: https://github.com/quchen/stgi

Answer 3

There is an online hosted visual demonstration here with an explanation here.

Typelead was a briefly funded startup that attempted to fork GHC to the JVM (before they ran out of money). Etalang was the result and it contains a STG. You can read the code of the STG here.