GAP test file language support for VSCode

This VSCode extension provides syntax highlighting support for GAP system test files (extension .tst). For more info on gap test files see the Chapter 7 of the GAP reference manual.

The underlying grammar implements the bare minimum required features for parsing GAP test file output, delegating the highlighting of actual GAP code to existing GAP grammars via the embeddedLanguages property. This means that another plugin is required for syntax highlighting the actual GAP code itself. We currently use the GAP VSCode extension by ChrisJefferson for this.

Known issues

Due to the nature of the GAP test file format, namely the usage of empty lines to denote the end of a test case, output lines starting with a # character will be highlighted as comment strings instead of output blocks. This should occur sufficiently rarely so as not to cause any issues.