# Hacking on the Standard Library

Gerbil is a growing project and your contributions are welcome!

When working on modifications to the standard library, it's common to encounter errors such as:

*** ERROR IN gx#core-expand-import%__% -- 
*** ERROR IN "file.ss"@1.9
--- Syntax Error: Cannot find library module
... form:   :std/my/module

This typically because the gxi or gxc being used is looking at the installed standard library which will not contain your changes. To address this, run your environment with the build.sh script after building.

Example build:

./build.sh

To test your local changes rebuild the stdlib and then use the locally built gxi with the following commands:

./build.sh stdlib
./build.sh env gxi ../your-test-file.ss

NOTE: the execution environment when using ./build.sh env is in the src/ folder in the root of the Gerbil repo. Absolute paths work as normal, but relative paths must be adjusted for PWD change.