If you are used to using a full fledged Code Editor, then you will have had bad experiences with Code Expert, there's a distinct lack of customization and language support. That's what this Add-on intends to fix. Currently it supports these features:

Keybindings: allows you to use different default keybindings, for example Vim and VSCode
Options
- Click link to go to file: If you compile a C++ file and get a compilation error, you can Click on the file location in the Terminal and it will take you right to the Location of the error
- Fix scrollbar in Firefox: Code-Expert has an annoying bug in Firefox where the page is 50000 pixels wide, which adds an annoying scrollbar, this option fixes that
- Parse and Display Errors: If you compile a C++ file it will read the Output in the Terminal and add Error Markers inside the File
- Make FileTree Navigable: If you focus the FileTree, you can use your arrow keys (or hjkl if you have Vim mode enabled) to naviate the File Structure
Keyboard Shortcuts:
- Compile: Opens the Terminal and hits the Compile button (if available)
- Run: Opens the Terminal and hits the Run button
- Run Tests: Opens the Terminal and hits the Test button
- Format File: Uses either Ace of (if configured) an LSP to Format the current file
- Comment selection: Toggles the comments in the selected Lines
- Next Suggestion: Goes to the next Suggestion in Autocomplete (useful for Vim Mode)
- Previous Suggestion: Goes to the previous Suggestion in Autocomplete (useful for Vim Mode)
- Focus shortcuts: Focuses different parts of the editor

Advanced, if you have the time and will to try and setup a Native Executable, you can also run an LSP and get these features:

Auto Complete: Actually useful Auto Complete
Code Diagnostics: Shows you Errors and Warnings before you hit compile
Hover Diagnostics: Tells you everything about a Symbol when you hover over it
Formatting: Improved formatting