icu

In #1694 I added is_ascii_lowercase() (and uppercase and titlecase). The functions are defined to mean that if you apply to_ascii_lowercase() (or uppercase/titlecase), then you get back the same string.

However, many call sites are ending up looking like

s.is_ascii_alphabetic() && s.is_ascii_lowercase()

I think we should add functions that combine both checks and save a

Are there any cheat sheets of stringi available? Like this one of stringr: http://edrub.in/CheatSheets/cheatSheetStringr.pdf

It would be more efficient to have a cheat sheet since R base, stringr, and stringi have different but similar types of syntax, which could be confusing some times.

Right now we only support either a custom message syntax validator or the ICU Message Syntax. We can start to add builtin support for other syntaxes