Serializer should not override letter casing in language and script tags

[rjyounes]

While lettercase is not significant in IANA language and script tags, the following conventions typically apply:

• lowercase for language (e.g., "de")
• uppercase for region (eg., "de-DE")
• capitalized for script (e.g., "mn-Cyrl")

The serializer capitalizes the script portion, thus converting "mn-Cyrl" to "mn-CYRL." Again, since the case is not significant, this doesn't produce processing errors, but there is really no reason for the serializer to modify the input.

Note that there was a related issue that was fixed.

[mereolog]

This feature was requested in https://github.com/edmcouncil/rdf-toolkit/issues/32 by @ElisaKendall as a remedy to the "opposite" behaviour of Protege.

I think we can add a new parameter, e.g., capitalize_suffix_in_language_tags, with the default value True to handle problem you indicated.

[rjyounes]

There are a number of subtag standards included in the IETF standard, and language casing depends on the standard. The most common subtags are for region, which are two uppercase letters, as in issue #32, and script, which are four title case letters (I.e., initial upper and remainder lower, as in "Cyrl"). The private use subtag x (from my issue #60) is lowercase. You can thus use number of characters to determine the appropriate letter casing. Note that the region and script subtags can stack up.

There are some tags that won't be caught in this net, such as gsw-u-sd-chzh for Zürich German, but these are quite specialized. The distinction between two- and four-letter subtags will catch most uses.

[mereolog]

There are a number of subtag standards included in the IETF standard, and language casing depends on the standard. The most common subtags are for region, which are two uppercase letters, as in issue #32, and script, which are four title case letters (I.e., initial upper and remainder lower, as in "Cyrl"). The private use subtag x (from my issue #60) is lowercase. You can thus use number of characters to determine the appropriate letter casing. Note that the region and script subtags can stack up.

There are some tags that won't be caught in this net, such as gsw-u-sd-chzh for Zürich German, but these are quite specialized. The distinction between two- and four-letter subtags will catch most uses.

Thanks for this insight.

Just to make sure that I got you right - do you suggest that we:

• capitalize two-letter subtags
• do not change four-letter subtags ?

[rjyounes]

Yes, that's my proposal. You may want to get a second opinion because I'm not an expert in this area.

[mereolog]

Yes, that's my proposal. You may want to get a second opinion because I'm not an expert in this area.

@ElisaKendall could you advise?

[rjyounes]

I see there's a fix ready to go for this issue, and it doesn't seem you're going to get a response from @ElisaKendall. Do you feel confident enough in the fix to go ahead and merge the PR? My judgement is that it still may not be correct in all cases, but it will fix some errors and not create any new ones - thus you'll be ahead overall by including it.