Basically just the title said. The situation is basically I use a Domain-Specific Language called G’MIC, and to this day, I haven’t found a satisfactory answer to the issue of lack of syntax highlighting. At the moment, I am using KDE Kate as it’s pretty good at structuring the code with their find/replace feature, tab indicators, and multi-window support.
I can second this. I wrote a syntax highlighter for a DSL in Sublime ages ago and all I remember is that it was easy.
That said, you can definitely do this in VS Code, too (just I haven’t personally tried it). IMO VS Code is the better editor.
VSCode and Sublime use a TextMate-like format and can be converted between the two. I have made language support and recommend VSCode.