I'm making a major mode for json (which has no comments), and using SMIE for 'free' indenting.

I've currently got a half-baked grammar called json-grammar, and no rules-function.

Consequently, I'm invoking smie-setup as

(smie-setup json-grammar (lambda (method arg) ()))

However, in a few places I'm calling smie-indent-line, and when I do, smie-indent-line eventually calls comment-normalize-vars

This function asks for a value comment syntax, and insists on having some value. Given that I want to use SMIE for indentation, how can I avoid this problem?

  • Would hacking together a regexp that will never match anything work? (Maybe $; will do)
    – PythonNut
    Commented Aug 13, 2015 at 14:42

1 Answer 1


You'll probably want to use dummy comment settings. E.g. "#" for comment-start and "\\`.\\`" for comment-start-skip.

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