I don't know why anyone would name their project "slint" (or its previous name "60fps" which made no sense). I also don't know why anyone would want a bulky DS

I don't know why anyone would name their project "slint" (or its previous name "60fps" which made no sense). I also don't know why anyone would want a bulky DSL to declare a GUI. Declaring a GUI is the easy part. It's attributes and data that mostly don't need to be changed by the user. Just call C++ functions to get the data into the library. When DSLs start to come in to play you have an entire secondary language to worry about. Everything from parsing to type conversions to character sets to byte codes is suddenly a potential problem and it doesn't need to be because it doesn't solve anything difficult in the first place.