Problem: Several tag and attribute names are highlighted with regular
expression alternations even though they are plain words. A
:syn-match with an alternation is retried at nearly every
position of every tag.
Solution: Move the plain-word tag names (b, i, u, em, strong, head,
body, title, h1-h6) and the "label", "href" and "title"
attribute names into syn-keyword lists, leaving only the
genuinely hyphenated names "accept-charset" and "http-equiv"
as matches.
Profiling a 6000-line HTML file with :syntime, the converted rules drop
from a combined 0.044s to 0.004s, lowering total per-rule syntax time
by about 15%. Highlighting is unchanged except that a bare valueless
"href" attribute is now highlighted as an attribute, consistent with a
bare "title", which already behaved that way.
closes: vim/vim#21155https://github.com/vim/vim/commit/964a495bef698368f4e200b1d22d63da27f47948
Co-authored-by: Julien Voisin <julien.voisin@dustri.org>
Tag folding poses a few difficulties. Many elements, e.g.
"blockquote", are always delimited by start and end tags;
end tags for some elements, e.g. "p", can be omitted in
certain contexts; void elements, e.g. "hr", have no end tag.
Although the rules for supporting omissible end tags are
ad-hoc and involved, they apply to elements in scope.
Assuming syntactical wellformedness, an end tag can be
associated with its nearest matching start tag discoverable
in scope and towards the beginning of a file, whereas all
unbalanced tags and inlined tags can be disregarded.
For example:
------------------------------------------------------------
<!DOCTYPE html>
<html lang="en"> <!-- >1 : 1 -->
<body> <!-- >2 : 2 -->
<p>Paragraph vim/vim#1. <!-- = : 2 -->
<p> <!-- >3 : 3 -->
Paragraph vim/vim#2. <!-- = : 3 -->
</p> <!-- <3 : 3 -->
<p>Paragraph vim/vim#3.</p> <!-- = : 2 -->
</body> <!-- <2 : 2 -->
</html> <!-- <1 : 1 -->
------------------------------------------------------------
(HTML comments here, "<!-- ... -->", record two values for
each folded line that are separated by ":", a value obtained
from "&foldexpr" and a value obtained from "foldlevel()".)
Innermost foldedable tags will be flattened. For example:
------------------------------------------------------------
<!DOCTYPE html>
<html lang="en"> <!-- >1 : 1 -->
<body> <!-- >2 : 2 -->
<div class="block"> <!-- >3 : 3 -->
<pre><code> <!-- >4 : 4 -->
[CODE SNIPPET] <!-- = : 4 -->
</code></pre> <!-- <4 : 4 -->
</div> <!-- <3 : 3 -->
</body> <!-- <2 : 2 -->
</html> <!-- <1 : 1 -->
------------------------------------------------------------
No folding will be requested for the "<code>"-"</code>" tag
pair and reflected by "&foldexpr" because such a fold would
have claimed the same lines that the immediate fold of the
"<pre>"-"</pre>" tag already claims.
Run-on folded tags may confuse Vim. When a file such as:
------------------------------------------------------------
<!DOCTYPE html>
<html lang="en"> <!-- >1 : 1 -->
<body> <!-- >2 : 2 -->
<div class="block"> <!-- >3 : 3 -->
<pre> <!-- >4 : 4 -->
<code> <!-- >5 : 5 -->
[CODE SNIPPET vim/vim#1] <!-- = : 5 -->
</code> <!-- <5 : 5 -->
</pre> <!-- <4 : 4 -->
</div> <!-- <3 : 3 -->
<!-- = : 3 -->
<div class="block"> <!-- >3 : 3 -->
<pre> <!-- >4 : 4 -->
<code> <!-- >5 : 5 -->
[CODE SNIPPET vim/vim#2] <!-- = : 5 -->
</code> <!-- <5 : 5 -->
</pre> <!-- <4 : 4 -->
</div> <!-- <3 : 3 -->
</body> <!-- <2 : 2 -->
</html> <!-- <1 : 1 -->
------------------------------------------------------------
is reformatted as follows:
------------------------------------------------------------
<!DOCTYPE html>
<html lang="en"> <!-- >1 : 1 -->
<body> <!-- >2 : 2 -->
<div class="block"> <!-- >3 : 3 -->
<pre> <!-- >4 : 4 -->
<code> <!-- >5 : 5 -->
[CODE SNIPPET vim/vim#1] <!-- = : 5 -->
</code> <!-- <5 : 5 -->
</pre> <!-- <4 : 4 -->
</div><div class="block"><pre><code> <!-- <3 : 3 -->
[CODE SNIPPET vim/vim#2] <!-- = : 2 ? -->
</code> <!-- <5 : 2 ? -->
</pre> <!-- <4 : 2 ? -->
</div> <!-- <3 : 2 ? -->
</body> <!-- <2 : 2 -->
</html> <!-- <1 : 1 -->
------------------------------------------------------------
"&foldexpr" values will not be used as is for the lines
between (and including) "[CODE SNIPPET vim/vim#2]" and "</div>".
(Cf. v9.1.0002.)
Having syntax highlighting in effect, tag folding using the
"fold-expr" method can be enabled with:
------------------------------------------------------------
let g:html_expr_folding = 1
------------------------------------------------------------
By default, tag folding will be redone from scratch after
each occurrence of a TextChanged or an InsertLeave event.
Such frequency may not be desired, especially for large
files, and this recomputation can be disabled with:
------------------------------------------------------------
let g:html_expr_folding_without_recomputation = 1
doautocmd FileType
------------------------------------------------------------
To force another recomputation, do:
------------------------------------------------------------
unlet! b:foldsmap
normal zx
------------------------------------------------------------
References:
https://web.archive.org/web/20250328105626/https://html.spec.whatwg.org/multipage/syntax.html#optional-tagshttps://en.wikipedia.org/wiki/Dangling_elsecloses: vim/vim#17141https://github.com/vim/vim/commit/dc7ed8f946a3109460435221ad45f92486c4ebca
Co-authored-by: Aliaksei Budavei <0x000c70@gmail.com>
Vim runtime files based on 7.4.384 / hg changeset 7090d7f160f7
Excluding:
Amiga icons (*.info, icons/)
doc/hangulin.txt
tutor/
spell/
lang/ (only used for menu translations)
macros/maze/, macros/hanoi/, macros/life/, macros/urm/
These were used to test vi compatibility.
termcap
"Demonstration of a termcap file (for the Amiga and Archimedes)"
Helped-by: Rich Wareham <rjw57@cam.ac.uk>
Helped-by: John <john.schmidt.h@gmail.com>
Helped-by: Yann <yann@yann-salaun.com>
Helped-by: Christophe Badoit <c.badoit@lesiteimmo.com>
Helped-by: drasill <github@tof2k.com>
Helped-by: Tae Sandoval Murgan <taecilla@gmail.com>
Helped-by: Lowe Thiderman <lowe.thiderman@gmail.com>
