[R] Bindings for stringr::str_to_sentence

[asfimport]

There is more to this issue than meets the eye. The stringr::str_to_sentence() does 2 things:

• capitalise the first word

• if there are multiple sentences provided as a single string, attempts to find sentence breaks and capitalise the first word of each sentence.

  The stringr implementation wraps stringi::str_trans_totitle(), which in turns uses ICU’s BreakIterator to locate specific text boundaries. As a consequence stringr::str_to_title() is not able to identify a full stop / period (".") as a sentence end and does not capitalise words following it. Thus, there is a discrepancy between behaviour of the utf8_capitalize kernel (which capitalises the first word of a string without making any attempt to break into sentences) and the behaviour of stringr::str_to_sentence().

  For more extensive discussions around the stringi / stringr implementation see stringr issues 202 and 231.

  Due to the complexity of this issue and the relatively niche use cases, the recommendation is to postpone implementation.

Reporter: Nicola Crane / @thisisnic
Assignee: Dragoș Moldovan-Grünfeld / @dragosmg

Related issues:

• [C++] String capitalize kernel (depends upon)

PRs and other links:

• GitHub Pull Request #11484

_{Note: This issue was originally created as ARROW-13615. Please see the migration documentation for further details.}