Hoist the `eval-when-compile` to encompass the entire list, since
backquote forms aren't automatically evaluated at compile time.
This results in a single constant list in the generated code, and
much less actual code.
There is a conflict between forward matching and backward matching
composition rules involving the same codepoint, which can cause the
backward matching ones not to be invoked. Ensure that VS-15 (U+FE0E)
and VS-16 (U+FE0F) are composed by forward matching rules instead in
order to avoid this issue.
* admin/unidata/emoji-zwj.awk: Add rules for CHAR+VS-15 and CHAR+VS-16.
* lisp/composite.el: remove backward matching rule for VS-15. (Bug#63731)
* admin/unidata/blocks.awk: Remove emoji overrides for codepoints with
Emoji_Presentation = No, they're no longer necessary.
* lisp/composite.el: Remove #xFE0F (VS-16) from the range handled by
`compose-gstring-for-variation-glyph' so it can be handled by
`font_range'.
* src/composite.c (syms_of_composite): New variable
`auto-composition-emoji-eligible-codepoints'.
* admin/unidata/emoji-zwj.awk: Generate value for
`auto-composition-emoji-eligible-codepoints'. Add
`composition-function-table' entries for 'codepoint + U+FE0F' for
them.
* src/font.c (codepoint_is_emoji_eligible): New function to check if
we should try to use the emoji font for a codepoint.
(font_range): Use it.
Read skin tone modifier sequences from emoji-sequences.txt and add
them to the per-character composition rules derived from
emoji-zwj-sequences.txt, rather than adding them as lookback rules for
the skin tone modifiers. This avoids an issue with the application of
such lookback rules. See Bug#39799,
specifically
<https://lists.gnu.org/archive/html/bug-gnu-emacs/2021-09/msg01878.html>
for more details.
* admin/unidata/Makefile.in (zwj): Add emoji-sequences.txt as a dependency.
* admin/unidata/emoji-zwj.awk: Match RGI_Emoji_ZWJ_Sequence and
RGI_Emoji_Modifier_Sequence. Remove manual addition of skin tone
composition rules with lookback.
This covers both sequences using Zero-Width-Joiner codepoints and
those without. Bug#39799, I hope.
* .gitignore: Add emoji-zwj.el
* admin/notes/unicode: Add emoji-zwj-sequences.txt and
emoji-sequences.txt references. Describe how to test after updating
to a newer Unicode version.
* admin/unidata/Makefile.in (all): add emoji-zwj.el as a dependency.
(emoji-zwj.el): Add target plus rules for building.
(gen-clean): Add emoji-zwj.el.
* admin/unidata/README: Add emoji-zwj-sequences.txt and
emoji-sequences.txt references.
* admin/unidata/blocks.awk: Force emoji script to be used for certain
codepoints that are used by the Unicode sequences.
* admin/unidata/emoji-sequences.txt: New file.
* admin/unidata/emoji-zwj-sequences.txt: New file.
* admin/unidata/emoji-zwj.awk: New file. Derives
composition-function-table rules from emoji-zwj-sequences.txt, plus
hardcodes some derived manually from emoji-sequences.txt.
* etc/NEWS: Announce change.
* lisp/international/characters.el: Load the generated emoji-zwj.el
* src/Makefile.in (emoji-zwj): New target.
(temacs): Add emoji-zwj as a dependency.
