BCP 47 will be the single source of truth for known calendar and number
system keywords, and their aliases (e.g. "gregory" is an alias for
"gregorian"). Move the generation of available keywords to where we
parse the BCP 47 data, so that hard-coded aliases may be removed from
other generators.
We have a fair amount of hard-coded keywords / aliases that can now be
replaced with real data from BCP 47. As a result, the also changes the
awkward way we were previously generating keys. Before, we were more or
less generating keywords as a CSV list of keys, e.g. for the "nu" key,
we'd generate "latn,arab,grek" (ordered by locale preference). Then at
runtime, we'd split on the comma. We now just generate spans of keywords
directly.
As we didn't (and still don't) have Intl.PluralRules when we implemented
Intl.NumberFormat, we use a locale-unaware basic implementation to pick
a pattern based on a number's value. Templatize this method for now to
work other other format-like structures (will be used for relative-time
formatting).
Relative-time format patterns are of one of two forms:
* Tensed - refer to the past or the future, e.g. "N years ago" or
"in N years".
* Numbered - refer to a specific numeric value, e.g. "in 1 year"
becomes "next year" and "in 0 years" becomes "this year".
In ECMA-402, tensed and numbered refer to the numeric formatting options
of "always" and "auto", respectively.
Previously, we were breaking up digits into groups without regard for
the locale's minimumGroupingDigits value in the CLDR. This value is 1 in
most locales, but is 2 in locales such as pl-PL. What this means is that
in those locales, the group separator should only be inserted if the
thousands group has at least 2 digits. So 1000 is formatted as "1,000"
in en-US, but "1000" in pl-PL. And 10000 is "10,000" in en-US and
"10 000" in pl-PL.
This is no longer needed now that LibTimeZone is included within LibC.
Remove the direct linkage so that others do not mistakenly copy-paste
the CMakeLists text elsewhere.
Currently, the UnicodeLocale generator collects a list of known locales
from the CLDR before processing language display names. For each locale,
the identifier is broken into language, script, and region subtags, and
we create a list of seen languages. When processing display names, we
skip languages we hadn't seen in that first step.
This is insufficient for language display names like "en-GB", which do
not have an locale entry in the CLDR, and thus are skipped. So instead,
create the list of known languages by actually reading through the list
of languages which have a display name.
These patterns indicate how to display locale strings when that locale
contains multiple subtags. For example, "en-US" would be displayed as
"English (United States)".
Before LibUnicode generated methods were weakly linked, we had a public
method (get_locale_currency_mapping) for retrieving currency mappings.
That method invoked one of several style-specific methods that only
existed in the generated UnicodeLocale.
One caveat of weakly linked functions is that every such function must
have a public declaration. The result is that each of those styled
methods are declared publicly, which makes the wrapper redundant
because it is just as easy to invoke the method for the desired style.
Note there's a bit of an unfortunate duplication in the calendar enum
generated by UnicodeLocale and the existing enum generated by
UnicodeDateTimeFormat. The former contains every calendar known to the
CLDR, whereas the latter contains the calendars we've actually parsed
for DateTimeFormat (currently only Gregorian). The new enum generated
here can be removed once DateTimeFormat knows about all calendars.
We had a hard-coded table of number system digits copied from ECMA-402.
Turns out these digits are in the CLDR, so let's parse the digits from
there instead of hard-coding them.
The following table in TR-35 includes a web of fall back rules when the
requested time zone style is unavailable:
https://unicode.org/reports/tr35/tr35-dates.html#dfst-zone
Conveniently, the subset of styles supported by ECMA-402 (and therefore
LibUnicode) all either fall back to GMT offset or to a style that is
unsupported but itself falls back to GMT offset.
This adds an API to use LibTimeZone to convert a time zone such as
"America/New_York" to a GMT offset string like "GMT-5" (short form) or
"GMT-05:00" (long form).
There are a few algorithms in TR-35 that need to replace digits before
returning any results to callers. For example, when formatting time zone
offsets, a string like "GMT+12:34" must have its digits replaced with
the default numbering system for the desired locale.
LibUnicode no longer needs to generate a list of time zone names that it
parsed from metaZones.json. We can defer to the TZDB for a golden list
of time zones.
The generator parses metaZones.json to form a mapping of meta zones to
time zones (AKA "golden zone" in TR-35). This parser errantly assumed
this was a 1-to-1 mapping.
Currently, we load the generated Unicode symbols with dlopen at runtime.
This is unnecessary as of 565a880ce5.
Applications that want Unicode data now link directly against the shared
library holding that data. So the same functionality can be achieved
with weak symbols.
ECMA-402 now supports short-offset, long-offset, short-generic, and
long-generic time zone name formatting. For example, in the en-US locale
the America/Eastern time zone would be formatted as:
short-offset: GMT-5
long-offset: GMT-05:00
short-generic: ET
long-generic: Eastern Time
We currently only support the UTC time zone, however. Therefore, this
very minimal implementation does not consider GMT offset or generic
display names. Instead, the CLDR defines specific strings for UTC.
The generated data for libunicodedata.so is quite large, and loading it
is a price paid by nearly every application by way of depending on
LibRegex. In order to defer this cost until an application actually uses
one of the surrounding APIs, dynamically load the generated symbols.
To be able to load the symbols dynamically, the generated methods must
have demangled names. Typically, this is accomplished with `extern "C"`
blocks. The clang toolchain complains about this here because the types
returned from the generators are strictly C++ types. So to demangle the
names, we use the asm() compiler directive to manually define a symbol
name; the caveat is that we *must* be sure the symbols are unique. As an
extra precaution, we prefix each symbol name with "unicode_". For more
details, see: https://gcc.gnu.org/onlinedocs/gcc/Asm-Labels.html
This symbol loader used in this implementation provides the additional
benefit of removing many [[maybe_unused]] attributes from the LibUnicode
methods. Internally, if ENABLE_UNICODE_DATABASE_DOWNLOAD is OFF, the
loader is able to stub out the function pointers it returns.
Note that as of this commit, LibUnicode is still directly linked against
LibUnicodeData. This commit is just a first step towards removing that.
