[https://github.com/jonathancast/hsglobalscript3 Available here]; you will also need the language spec, [https://github.com/jonathancast/globalscript-spec here].
This implementation is based on a translator for Global Script code embedded in a Haskell source file; to get a working program, you will need to add
import GSI.Env (runGSProgram)
$gsimports
main = runGSProgram $ [gs:value|
-- Global Script code goes here
|]
around the program, then compile and run that with a Haskell compiler.