This implements unconditional special case folding, and conditional
folding for non-locale cases. Worth noting that the only conditional,
non-locale special case is for converting an uppercase sigma to
lowercase.
This will be needed for the Unicode Standard's Default Case Algorithm.
Generate the field as an enumeration rather than a string for easier
comparison.
This adds a SpecialCasing structure to the generated UnicodeData.h/cpp
files. This structure contains casing rules for code points which have
non-1-to-1 upper-to-lower case code point mappings. Further, these rules
may be limited to specific locales or other context.
This is primarily to allow using LibUnicode within LibJS and its REPL.
Note: this seems to be the first time that a Lagom dependency requires
generated source files. For this to work, some of Lagom's CMakeLists.txt
commands needed to be re-organized to include the CMake files that fetch
and parse UnicodeData.txt. The paths required to invoke the generator
also differ depending on what is currently building (SerenityOS vs.
Lagom as part of the Serenity build vs. a standalone Lagom build).
The Unicode standard publishes the Unicode Character Database (UCD) with
information about every code point, such as each code point's upper case
mapping. LibUnicode exists to download and parse UCD files at build time
and to provide accessors to that data.
As a start, LibUnicode includes upper- and lower-case code point
converters.
