[Latex] Support highlighting \ExplSyntaxOn and \ExplSyntaxOff code blocks

[evandrocoan]

• Operating system and version:
  • Windows 10 build 15063 x64
  • Resolution 1920x1080
  • dpi_scale 1.0
  • Sublime Text:
  • Build 3207
  • 64 bit

Example code:

% Some usual latex
\documentclass[english]{article}
\usepackage{babel}
\usepackage{xparse}
\usepackage{hyperref}
\usepackage{cleveref}

% New syntax to support start here
\ExplSyntaxOn

% #1: variant (cref, Cref, crefs or Crefs)
% #2: reference name (label)
\cs_new_protected:Npn \user_name_cref:nn #1#2
  { \use:c { name #1 } {#2} }

\cs_generate_variant:Nn \user_name_cref:nn { xV }

% #1: boolean expression (true: disable hyperlink)
% #2: reference name (label)
\cs_new_protected:Npn \user_name_ref:nn #1#2
  { \bool_if:nTF {#1} { \nameref* } { \nameref } {#2} }

\cs_generate_variant:Nn \user_name_ref:nn { nV }

\seq_new:N \l__user_name_refs_tmpa_seq
\seq_new:N \l__user_name_refs_tmpb_seq
\int_new:N \l__user_name_refs_nbrefs_int
\tl_new:N \l__user_name_refs_firstref_tl

% #1: boolean expression (true: start with capitalized letter, as in \Cref)
% #2: boolean expression (true: disable hyperlinks)
% #3: comma list of refs
\cs_new_protected:Npn \user_name_refs:nnn #1#2#3
  {
    \seq_set_from_clist:Nn \l__user_name_refs_tmpa_seq {#3}
    \int_set:Nn \l__user_name_refs_nbrefs_int
                { \seq_count:N \l__user_name_refs_tmpa_seq }
    \seq_get_left:NN \l__user_name_refs_tmpa_seq \l__user_name_refs_firstref_tl

    % (section, Section, sections or Sections) or (theorem, Theorem, ...) or...
    \user_name_cref:xV
      { \bool_if:nTF {#1} { C } { c }
        ref
       \int_compare:nNnTF { \l__user_name_refs_nbrefs_int } > { 1 } { s } { } }
     \l__user_name_refs_firstref_tl
    \nobreakspace

    % Now print the references.
    \seq_clear:N \l__user_name_refs_tmpb_seq
    \seq_map_inline:Nn \l__user_name_refs_tmpa_seq
      {
        \seq_put_right:Nn \l__user_name_refs_tmpb_seq
                          { \user_name_ref:nn {#2} {##1} }
      }
    \seq_use:Nnnn \l__user_name_refs_tmpb_seq { \crefpairconjunction }
                  { \crefmiddleconjunction } { \creflastconjunction }
  }

\cs_generate_variant:Nn \user_name_refs:nnn { nx }

\cs_new_protected:Npn \__user_name_refs:Nnn #1#2#3
  {
    \user_name_refs:nxn {#1}
      { \IfBooleanTF {#2} { \c_true_bool } { \c_false_bool } }
      {#3}
  }

% “Start in lower case” variant. With star: disable hyperlinks.
% #2: comma list of refs
\NewDocumentCommand \nameRefs { s m }
  {
    \__user_name_refs:Nnn \c_false_bool {#1} {#2}
  }

% “Start in upper case” variant. With star: disable hyperlinks.
% #2: comma list of refs
\NewDocumentCommand \NameRefs { s m }
  {
    \__user_name_refs:Nnn \c_true_bool {#1} {#2}
  }

% And it ends here
\ExplSyntaxOff

% More latex normal code
\begin{document}

References:
\begin{itemize}
\item With one reference and hyperlink: \nameRefs{first} (we'll disable
  hyperlinks from now on, because their default appearance is hideous and they
  don't behave very well across line breaks);
\item With one reference: \nameRefs*{first};
\item With two references: \nameRefs*{first, second};
\item With three references: \nameRefs*{first, second, third};
\item With four references: \nameRefs*{first, second, third, fourth};
\item Capitalized variant: \NameRefs*{first, second, third, fourth};
\item etc.
\end{itemize}

% This is a cref command; beware that spaces are not ignored after the commas!
For comparison, the \verb|\cref| command: \cref{first,second,third,fourth}.

\section{First section}
\label{first}

\section{Second section}
\label{second}

\section{Third section}
\label{third}

\section{Fourth section}
\label{fourth}

\end{document}

References:

1. https://tex.stackexchange.com/questions/108696/what-do-explsyntaxon-and-explsyntaxoff-do
2. https://tex.stackexchange.com/questions/505351/how-to-nameref-multiple-labels-simultaneously
3. expl3 syntax highlighting textmate/latex.tmbundle#79 expl3 syntax highlighting

[ngc92]

Here is an attempt at making an expl3 sub-language. This does not allow for switching between syntaxes with
\ExplSyntaxOn/ \ExplSyntaxOff, but applies instead to the entire file.

%YAML 1.2
---
# http://www.sublimetext.com/docs/3/syntax.html
name: Expl3
scope: text.tex.latex.expl3

file_extensions:
  - sty
  - cls
  - tex

extends: Packages/LaTeX/LaTeX.sublime-syntax

variables:
  scoped_var_name: '(__)?(_)?(?:([A-Za-z]+)(_))?([A-Za-z_]+)(_)(bool|box|cctab|clist|coffin|dim|fp|ior|iow|int|muskip|prop|seq|skip|str|tl)'

contexts:
  general-commands:
      - meta_prepend: true
      - include: expl3-fun
      - include: expl3-var

  general-constants:
    - meta_prepend: true
    # we need to ensure that \__ will be matched as the start of a command name,
    # not as an escaped underscore !
    - match: '(?=(\\)__)'
      push:
        # try to match a function, and immediately leave the context
        - include: expl3-fun
        - match: ''
          pop: true

  expl3-fun:
    - match: '(\\)(__)?([A-Za-z]+)(_)([A-Za-z_]+)(:)([nNpTFDwcVvxefo]+)'
      scope: variable.function.expl3
      captures:
        1: punctuation.definition.backslash.expl3
        2: storage.modifier.private.expl3
        3: entity.name.namespace.expl3
        4: punctuation.accessor.underscore.expl3
        6: punctuation.separator.annotation.expl3
        7: meta.annotation.parameters.expl3

  expl3-var:
    - match: '(\\)([lg]){{scoped_var_name}}'
      scope: variable.other.readwrite.expl3 support.function.expl3
      captures:
        1: punctuation.definition.backslash.expl3
        2: storage.modifier.expl3
        3: storage.modifier.expl3
        4: punctuation.separator.expl3
        5: entity.name.namespace.expl3
        6: punctuation.separator.expl3
        8: punctuation.separator.annotation.expl3
        9: variable.annotation.expl3
    - match: '(\\)(c){{scoped_var_name}}'
      scope: variable.other.constant.expl3 support.function.expl3
      captures:
        1: punctuation.definition.backslash.expl3
        2: storage.modifier.expl3
        3: storage.modifier.expl3
        4: punctuation.separator.expl3
        5: entity.name.namespace.expl3
        6: punctuation.separator.expl3
        8: punctuation.separator.annotation.expl3
        9: variable.annotation.expl3

The expl3 part of the example above then looks like

[mgkurtz]

Nice ♥️

Are there any chances of adding this to the latex syntax highlighting? That would be really great for viewing the lots of LaTeX3 code that exists nowadays.

Given that @ngc92’s syntax definition is rather precise and the fact that _ is usually not allowed outside math mode, there should be only rather few regressions: some\abc_x: appearing in a math formula, or when giving file names including a macro like \url{http://example.org/\basename_xyz:new.html}. Both seems rather rare.