This is a rewrite of the default syntax/tex.vim used for TeX/LaTeX, because I finally got fed-up with the default syntax/tex.vim file. My main complaints were that syntax folding is painfully slow for large files and doesn't work the way I want. Also spell checking checking missed many things I wanted checked (and erratically failed).

1. Syntax folding. If you set fdm=syntax, the document will be folded like this:

    +--  6 lines: \documentclass[draft]{amsart}-------------
    \begin{document}
    +-- 27 lines: \title[Continuity theorem for Bernstein tr
    +--169 lines: \section{Introduction.}\label{sxnIntro}---
    +-- 12 lines: \section{Continuity theorem.}\label{sxnCT}
    +--  3 lines: \bibliographystyle{habbrv}----------------
    \end{document}
   

   Additionally theorems, lemmas, proofs etc. are also folded, manual folds can be added. Syntax folding is about 3 to 4 times faster than the default syntax script shipped with Vim. This only make a difference if you edit large files. On my system, a file with 15,000 lines (and multiple sections / subsections / etc.) takes about 7 seconds to highlight and fold with this script, and it takes about 27 with the Vim default syntax script. Both scripts are snappy if folding is disabled, of course. If you plan on editing large TeX/LaTeX files and using syntax folding I recommend using the [FastFold] plugin in addition to this script.

2. Spell checking. Most everything that should be spell checked is. Arguments of all commands (except special commands in g:tex_special_commands) are spell checked, and arguments of environments (except theorem like environments in g:tex_thm_envs) are not spell checked.

3. Brace matching. Extra open braces in an environment will produce an error in the enclosing \end{...} statement. Extra closed braces are flagged. Braces denoting command and script script arguments are highlighted differently.

4. Concealing Greek characters and Symbols. If you set conceallevel to 1 or 2 and are using UTF-8 encoding, then commands like \alpha or \nabla will be shown as α or ∇ respectively.

g:tex_special_arg_commands : Space separated list of commands with special arguments (e.g. usepackage). Arguments of these commands will be colored and not spell checked.

g:tex_special_commands : Space separated list of special commands (e.g. large). These will be colored differently from other commands (but the arguments will not be handled specially).

g:tex_section_commands : Space separated list of sectioning commands (e.g. chapter).

g:tex_math_text_commands : Space separated list of commands in math mode with text arguments (e.g. text).

g:tex_thm_envs : Space separated list of theorem like environments (e.g. theorem). Arguments of these commands are spell checked (and not colored).

g:tex_math_envs : Space separated list of environment names that start a math zone (e.g. equation etc.),

g:tex_fold_envs : Set this to a space separated list of environment names that should start a fold.

g:tex_isk : iskeyword option for TeX/LaTeX files.

In case the automatically created syntax folds created are not sufficient for your purposes, you can adjust it manually in the following ways.

1. The comment markers %{{{ and %}}} can be used to create a fold. The numbered versions %{{{1, %}}}1 etc. are ignored.

2. Section / subsection level folds can manually be started using %startsection, %startsubsection or %startsubsubsection. (Similarly for chapters).

3. Section / subsection level folds can be manually closed using using %endsection, %endsubsection or %endsubsubsection. (Similarly for chapters)

4. The front matter fold (that starts on the line after \begin{document}) usually ends when a section or chapter is started. If you want to end it earlier, use the comment %endfrontmatter

• Github page

• Gitlab page

• Vim script page