This is an experimental plugin for IntelliJ to provide IDE-like functionality.

Developing the plugin requires that you have the IntelliJ community edition source code and various plugins installed. These are required if you are modifying the lexers or parsers. Otherwise, you can use the generated versions of the files that we have committed.

Currently, the easiest way is to follow the tutorial for writing a custom language plugin.

Be sure to also disable the external compiler via the Settings → Compiler → Use external build option.

To run the plugin in a separate IntelliJ IDEA instance you need to add a run configuration. To do this open the Run/Debug Configurations window (via Run → Edit Configurations...), click the + button and choose Plugin. You can rename your configuration to a more descriptive name such as "DeftIDEA".