Is there a text editor that would allow me to create syntax highlighting easily?

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.