Any text editor can be used to edit xRPL files. However, syntax highlight and auto completion makes coding a lot easier. Support files are provided for several available editors.
Notepad++ is a popular, free, open-source editor.
Notepad++ can be obtained from here: http://notepad-plus-plus.org/
https://knucklecracker.com/wiki/doku.php?id=crpl:docs:$(CURRENT_WORD)into the input field and click “Save”. After that, select a name (for example “Open CRPL Wiki”) and a keyboard shortcut (for example Ctrl+Shift+H) and click OK, then just close the Run… dialog. After that, you should see your shortcut in the “Run” menu, and you can use it to open the current command (the one that your input cursor is currently on) in the wiki.
By default, Notepad++ has a “reto” look (to put it kindly). The UI for it has not been revamped since inception. For those that prefer, notepad++ has several dark theme, and here is a link to a Material design. Clearly the UI can't be changed, but at least it will be less glaring on the eyes.
Visual Studio Code can be obtained from here: https://code.visualstudio.com/.
Sublime Text can be obtained from here: https://www.sublimetext.com/3.
Features include syntax highlighting and auto completion.
Forum user Arin112 (Discord: Arin112#8343) wrote a C-lookalike front-end translator that will produce xRPL code as output.
There is a reference to the translator (MplLang) on the forum , and the source code and examples are on Github.
Time permitting, this deserves a more complete treatment and probably a section of it's own.
Dokuwiki uses GeSHi syntax highlighting.