Introduce a more strict grammar

[yudai-nkt]

To make the maintainer's life easier, I...

• [ ] created at least 1 spec to cover my changes,
  • I'm afraid I have no experience of writing a spec, so I don't know how to. I don't think my commit is big enough to create a corresponding spec, but if it's really needed and someone is kind to make one, he or she is more than welcome!
• [x] npm tested my code and it's green like an :green_apple:,
  • Tests passed! :sparkles:
• [x] adjusted the readme.md, if it was necessary and
  • No need to change readme.md, I guess.
• [ ] would like to receive get a :beer: or :coffee: after that hard work!
  • No thanks, but I appreciate your kindness! :+1:

The current grammar is quite rough and it matches to anything in the form of key = value. This PR disallows matching to such malformed settings and only highlights valid ones listed in EditorConfig's Wiki. This will visually help users notice invalid lines (e.g., they made a typo or didn't remember the correct key/value name).

P.S. The default indent_style is set to tab in .editorconfig of this repo, but grammars/ini.cson uses 2-space indentation. I respected the consistency in a file.

[florianb]

Hey @yudai-nkt, thank you -- this is pretty good, i would love to add this to the next release.

Even though the new matchers are pretty more explicit they currently do not match uppercase values. I would appreciate if you could add case insensitiveness but i guess we need to use char-classes ([oO][fF][fF]) implement that.

I can do it, too but it will take its time.

P.s.: The .editorconfig of this repo is not complete. I need to add that rule.

[yudai-nkt]

I would appreciate if you could add case insensitiveness

Sure, I've added that feature. I didn't notice that EditorConfig is case insensitive although it's documented in Wiki.

[florianb]

Awesome! I wasn't aware of that, too.. 😄