Gosu 2026

Haven't used Gosu before. Exploring Java .jars, some syntax, dependencies, compilation, etc. Used a bit in the Insurance industry.

Setup and Use

docker compose up

# Exec in
## Three ways to interact with .gsp

## Gosu - change the package...
### Evaluates the full directory path as the classpath!
gosu src/main/gosu/thoughtscript/io/example/App.gsp

## Inline
gosu -e 'print(\"Hello world!\")'

## Maven
### Fresh compile before-hand...
mvn compile
mvn exec:java -Dexec.mainClass="thoughtscript.io.example.App"

Notes

1. Maven dependencies:
   • gosu-parent - contains synchronized dependencies, compiler settings, etc.
   • gosu-core and gosu-core-api - the actual language and interface.
   • (gosu-parent apparently contains both gosu-core and gosu-core-api.)
2. Although string and String are interchangeable (apparently, with the former being an alias for the latter akin to C# object and System.Object). the JIT Interpreter will cry foul:

   "string" is not a valid type. [line:6 col:30] in
   line 5:   //string is like C# System.Object alias for String...
   line 6:   static function main(args: string[]) {
   line 7:     print("Hello from the Main method!")
   Line Number: 6  Column: 30

3. The gosu JIT interpreter to execute .gsp scripts:

   gosu src/main/gosu/thoughtscript/io/example/App.gsp

   It seems that going this route requires that package thoughtscript.io.example be changed to: main.gosu.thoughtscript.io.example since it evaluate the full directory path as the classpath.
4. Maven:

   mvn clean install compile
   mvn exec:java -Dexec.mainClass="thoughtscript.io.example.App"

5. Gotcha's:
   • Cannot name Main.gsp and have Main Class within it otherwise it throws a redundant Class Error.
     • /app/src/main/gosu/thoughtscript/io/example/class/Example.gsp:[3,7] error: Duplicate class found at: thoughtscript.io.example.class.Example.Example.
   • There is no Main Method in Gosu.
   • Importing using package and uses. uses is primarily for importing Java libraries.
     • FYI - this exploratory example doesn't presently demontrate relative imports or uses.
   • Gosu dot notation for accessing fields. property for set and get.
   • gosu --version must be run in the Terminal - for some reason adding it to the Dockerfile results in an error.
   • Double WORKDIR in dockerfile due to recommended installation/setup.

Resources and Links

1. https://github.com/gosu-lang/example-commandline