To prepare for placing all CLDR generated data in a new library,
LibLocale, this moves the code generators for the CLDR data to the
LibLocale subfolder.
Each of these strings would previously rely on StringView's char const*
constructor overload, which would call __builtin_strlen on the string.
Since we now have operator ""sv, we can replace these with much simpler
versions. This opens the door to being able to remove
StringView(char const*).
No functional changes.
The PluralCategory enum is currently generated for plural rules. Instead
of generating it, this moves the enum to the public LibUnicode header.
While it was nice to auto-discover these values, they are well defined
by TR-35, and we will need their values from within the number format
code generator (which can't rely on the plural rules generator having
run yet). Further, number format will require additional values in the
enum that plural rules doesn't know about.
Plural rules in the CLDR are of the form:
"cs": {
"pluralRule-count-one": "i = 1 and v = 0 @integer 1",
"pluralRule-count-few": "i = 2..4 and v = 0 @integer 2~4",
"pluralRule-count-many": "v != 0 @decimal 0.0~1.5, 10.0, 100.0 ...",
"pluralRule-count-other": "@integer 0, 5~19, 100, 1000, 10000 ..."
}
The syntax is described here:
https://unicode.org/reports/tr35/tr35-numbers.html#Plural_rules_syntax
There are up to 2 sets of rules for each locale, a cardinal set and an
ordinal set. The approach here is to generate a C++ function for each
set of rules. Each condition in the rules (e.g. "i = 1 and v = 0") is
transpiled to a C++ if-statement within its function. Then lookup tables
are generated to match locales to their generated functions.
NOTE: -Wno-parentheses-equality is added to the LibUnicodeData compile
flags because the generated plural rules have lots of extra parentheses
(because e.g. we need to selectively negate and combine rules). The code
to generate only exactly the right number of parentheses is quite hairy,
so this just tells the compiler to ignore the extras.
