Unicode guide/Implementations

This page is my attempt to document my research on unique Unicode implementations supported in various languages and software. This is mostly in note form to avoid things getting out of control.

I apologize for not attaching sources to all of this, I've had to dig in to the source code. My best advice here it to

C and C++

C and C++ provide limited functionality related to text handling.

• Character type: 8-bit, 16-bit or 32-bit, encoding not defined
• Byte strings: No, just regular arrays
• Internal encoding: None
• String encoding: Depends on locale
• Supports bytes in strings: Depends on locale encoding
• Supports surrogates in strings: Depends on locale encoding
• Supports invalid code points in strings: Depends on locale encoding
• Supports normalizing strings: No
• Supports querying character properties: No
• Supports breaking by code point: No
• Supports breaking by extended grapheme cluster: No
• Supports breaking by text boundaries: No
• Supports encoding and decoding to other encodings: Yes
• Supports Unicode regex extensions: Not applicable, no regex included
• Classifies by: Locale information, only supports single characters
• Collates by: Locale information, supports arbitrary strings
• Converts case by: Locale information, only supports single characters
• Locale tailoring is done by: Current locale

This could be classified as 'Unicode agnostic' however classification and case conversion is limited to single characters. As a result this is just broken even with the limited functionality it provides.

Different platforms usually provide clearer definition:

• On POSIX, characters are usually 8-bit ASCII-compatible values
• On Windows, characters are 16-bit UTF-16-compatible values

Lua

Lua describes itself as 'encoding-agnostic', whatever that is. It certainly handles ASCII well.

• Character type: Byte, encoding not defined
• Byte strings: No
• Internal encoding: None
• String encoding: Undefined
• Supports bytes in strings: Depends on encoding
• Supports surrogates in strings: Depends on encoding
• Supports invalid code points in strings: Depends on encoding
• Supports normalizing strings: No
• Supports querying character properties: No
• Supports breaking by code point: Yes if encoded in UTF-8
• Supports breaking by extended grapheme cluster: No
• Supports breaking by text boundaries: No
• Supports encoding and decoding to other encodings: No
• Supports Unicode regex extensions: Not applicable, no regex at all
• Classifies by: C APIs, maybe by locale, only supports 8-bit characters
• Collates by: Doesn't provide an API for this
• Converts case by: C APIs, maybe by locale, only supports 8-bit characters
• Locale tailoring is done by: Per-process C locale

Overall there's no clear path here from reading bytes to handling Unicode.

Bonus points for the string.reverse function that will break Unicode strings.

Python 2

- check if this is worth mentioning

Python 3

python 3

Elixir

- erlang too?

PHP

- narrow APIs

- mbstring