
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-tags
https://en.wikipedia.org/wiki/Dangling_else
closes: vim/vim#17141
dc7ed8f946
Co-authored-by: Aliaksei Budavei <0x000c70@gmail.com>
Neovim is a project that seeks to aggressively refactor Vim in order to:
- Simplify maintenance and encourage contributions
- Split the work between multiple developers
- Enable advanced UIs without modifications to the core
- Maximize extensibility
See the Introduction wiki page and Roadmap for more information.
Features
- Modern GUIs
- API access from any language including C/C++, C#, Clojure, D, Elixir, Go, Haskell, Java/Kotlin, JavaScript/Node.js, Julia, Lisp, Lua, Perl, Python, Racket, Ruby, Rust
- Embedded, scriptable terminal emulator
- Asynchronous job control
- Shared data (shada) among multiple editor instances
- XDG base directories support
- Compatible with most Vim plugins, including Ruby and Python plugins
See :help nvim-features
for the full list, and :help news
for noteworthy changes in the latest version!
Install from package
Pre-built packages for Windows, macOS, and Linux are found on the Releases page.
Managed packages are in Homebrew, Debian, Ubuntu, Fedora, Arch Linux, Void Linux, Gentoo, and more!
Install from source
See BUILD.md and supported platforms for details.
The build is CMake-based, but a Makefile is provided as a convenience. After installing the dependencies, run the following command.
make CMAKE_BUILD_TYPE=RelWithDebInfo
sudo make install
To install to a non-default location:
make CMAKE_BUILD_TYPE=RelWithDebInfo CMAKE_INSTALL_PREFIX=/full/path/
make install
CMake hints for inspecting the build:
cmake --build build --target help
lists all build targets.build/CMakeCache.txt
(orcmake -LAH build/
) contains the resolved values of all CMake variables.build/compile_commands.json
shows the full compiler invocations for each translation unit.
Transitioning from Vim
See :help nvim-from-vim
for instructions.
Project layout
├─ cmake/ CMake utils
├─ cmake.config/ CMake defines
├─ cmake.deps/ subproject to fetch and build dependencies (optional)
├─ runtime/ plugins and docs
├─ src/nvim/ application source code (see src/nvim/README.md)
│ ├─ api/ API subsystem
│ ├─ eval/ Vimscript subsystem
│ ├─ event/ event-loop subsystem
│ ├─ generators/ code generation (pre-compilation)
│ ├─ lib/ generic data structures
│ ├─ lua/ Lua subsystem
│ ├─ msgpack_rpc/ RPC subsystem
│ ├─ os/ low-level platform code
│ └─ tui/ built-in UI
└─ test/ tests (see test/README.md)
License
Neovim contributions since b17d96 are licensed under the
Apache 2.0 license, except for contributions copied from Vim (identified by the
vim-patch
token). See LICENSE for details.
Vim is Charityware. You can use and copy it as much as you like, but you are
encouraged to make a donation for needy children in Uganda. Please see the
kcc section of the vim docs or visit the ICCF web site, available at these URLs:
https://iccf-holland.org/
https://www.vim.org/iccf/
https://www.iccf.nl/
You can also sponsor the development of Vim. Vim sponsors can vote for
features. The money goes to Uganda anyway.