This file contains the last properties that LibUnicode is not parsing.
Much of the data in this file is not currently used; that is left as a
FIXME for when String.prototype.normalize is implemented. Until then,
only the code point properties are utilized for regular expression
pattern escapes.
These script extensions have some peculiar behavior in the Unicode spec.
The UCD ScriptExtension file does not contain these scripts. Rather, it
is implied the code points which have these scripts as an extension are
the code points that both:
1. Have Common or Inherited as their primary script value
2. Do not have any other script value in their script extension lists
Because these are not explictly listed in the UCD, we must manually form
these script extensions.
Notice that unlike the note in populate_general_category_unions(),
script extension do indeed have code point ranges which overlap. Thus,
this commit adds code to handle that, and hooks it into the GC unions.
Previously, each code point's General Category was part of the generated
UnicodeData structure. This ultimately presented two problems, one
functional and one performance related:
* Some General Categories are applied to unassigned code points, for
example the Unassigned (Cn) category. Unassigned code points are
strictly excluded from UnicodeData.txt, so by relying on that file,
the generator is unable to handle these categories.
* Lookups for General Categories are slower when searching through the
large UnicodeData hash map. Even though lookups are O(1), the hash
function turned out to be slower than binary searching through a
category-specific table.
So, now a table is generated for each General Category. When querying a
code point for a category, a binary search is done on each code point
range in that category's table to check if code point has that category.
Further, General Categories are now parsed from the UCD file
DerivedGeneralCategory.txt. This file is a normal "prop list" file and
contains the categories for unassigned code points.
This was originally used for the "is_final_code_point" algorithm in
LibUnicode/CharacterTypes.cpp. However, it has since been superseded by
DerivedCoreProperties and is now unused. Remove it as it is currently a
waste of time to process the data, and is trivial to add back if we need
it again.
There are a couple of minor nuances with parsing script values, compared
to other properties. In Scripts.txt, the UCD file lists the full name of
each script; other properties, like General Category, list the shorter
name in their primary files. This means that the aliases listed in
PropertyValueAliases.txt are reversed for script values.
It takes a non-neglible amount of time to parse all of the UCD files and
generate the Unicode data files. To help compile times, only invoke the
generator once.
The current strategy of searching for a code point within the generated
table is slow for code points > U+0377 (the last code point whose index
is the same value as the code point itself). For larger code points, we
are doing a linear search through the table.
Instead, generate a HashMap of each code point to its entry in the table
for faster runtime lookups.
This had the added benefit of being able to remove a fair amount of code
from the generator. We no longer need to track that last contiguous code
point (U+0377) nor each code point's index in the generated table.
This downloads the PropertyValueAliases.txt UCD file, which contains a
set of General Category aliases.
This changes the General Category enumeration to now be generated as a
bitmask. This is to easily allow General Category unions. For example,
the LC (Cased_Letter) category is the union of the Ll, Lu, and Lt
categories.
Adds methods to retrieve a Unicode property from a string and to check
if a code point matches a Unicode property.
Also adds a <LibUnicode/Forward.h> header.
DerivedCoreProperties are pseudo-properties that are the union of other
categories and properties. For example, the derived property Math is the
union of the general category Sm and the property Other_Math.
Parsing these is necessary for implementing Unicode property escapes.
But it also has the added benefit that LibUnicode now does not need to
derive some of these properties at runtime.
Originally, this was done to make the generated enums look more like the
rest of Serenity's enums. But for Unicode property escapes, LibUnicode
will need to compare property names from a RegExp.prototype object to
these parsed property names, which will be easier without this
modification.
Rather than generating the PropList as a list of enums, generate it as
a bitmask. Not only will this be better for runtime property searching,
this will allow parsing of the DerivedCoreProperties list more easily.
There's a fair amount of boilerplate when e.g. adding a new UCD file to
parse or a new enumeration to generate. Reduce the overhead by adding
helper lambdas. Also adds a couple missing spec links with UCD field
information.
Note that unlike the main property list, each code point has only one
word break property. Code points that do not have a word break property
are to be assigned the property "Other".
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.
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.
