The special casing rules here handled by this function are specifically those in the argument c. See https://golang.org/pkg/unicode#SpecialCase.

There is a bit of background on this at http://www.unicode.org/reports/tr44/#Casemapping.

@ianlancetaylor - Does this sound okay ?

// ToUpperSpecial returns a copy of the string s with all Unicode letters mapped to their
// upper case, using the language-specific case mapping specified by c.
// You should use this function if you need to do case-insensitive string comparison
// in a specific language.

Hi, Can I take this issue as my first contribution? :)

Sure :)

@agnivade Thanks, I think the first sentence is fine but I would drop the second sentence. The truth is that if you want case-insensitive string comparison in a specific language you should probably be using golang.org/x/text/search.

@agnivade @ianlancetaylor I think the term special case in the go doc points to language-specific case mappings

Does this comment sounds good?

// ToUpperSpecial returns a copy of the string s with all Unicode letters mapped to their
// upper case, using the language-specific case mapping specified by c.
// Use this function if you need to do language-specific case mappings such as Turkish or Azeri.

I think the second sentence just repeats the last part of the first sentence. You can send a CL with only the first sentence. Users can always click on c to see more.

Change https://golang.org/cl/127716 mentions this issue: strings: revised ToUpperSpecial and ToLowerSpecial wording

@ianlancetaylor I just submitted a PR for this issue - as it is my first one let me know if anything is incorrect. I wasn't sure if anyone was still working on this since a few days had passed - my apologies if I stepped on any toes.

@kzisme I was working on this, as I can see your CL is under review, you can work on this. Thanks