I have made the beginnings of a JSON sugar. I copied the JavaScript sugar, deleted the parts that didn’t apply to JSON, and added a few more syntaxes. I didn’t do much to the plist in the Syntaxes folder, because I’m not really sure what it’s for. Also, apparently, a character may not have more than one syntax, because Espresso won’t think of ”[” as both a meta.brace.square.open.json and a punctuation.definition.array.begin.json – it just makes it whichever is first in the syntax file.
You can download it to try it out. To install, unzip and put in ~/Library/Application Support/Espresso/Sugars/ . I hope to continue working on this sugar, so suggestions or fixes are welcome.
