Xcode supports source code for the programming languages C, C++, Objective-C, Objective-C++, Java, AppleScript, Python, Ruby, ResEdit (Rez), and Swift, with a variety of programming models, including but not limited to Cocoa, Carbon, and Java.
Third parties have added support for GNU Pascal,[5] Free Pascal,[6] Ada,[7] C#,[8] Perl,[9] and D.[10]
Source : h ttps://en.wikipedia.org/wiki/Xcode
Which one would you want to add ?
I've never ventured in those areas. But there are XCode extensions.
https://developer.apple.com/documentation/xcodekit/creating_a_source_editor_extension
And a few implementation tutorials
h ttps://www.vadimbulavin.com/xcode-source-editor-extension-tutorial/
h ttps://code.tutsplus.com/tutorials/how-to-create-an-xcode-source-editor-extension--cms-26772
But that may not be enough to create a full fledge editor.