Snap! Gen

This is a code parser thing I made a while ago. I made it so it would work with my reverse codification project, and here is the result: Snap! 7.0.2 - Build Your Own Blocks
Syntax is just my reverse codification project's syntax.
Also,

Cool!

The help for the /append command refers to the "current line" but I can't see anywhere else that such an idea is found. What makes a line current?