matchedsplit

Matched delimiters across manually broken equations.

Version: 0.8.1 (2026-10-29) Author and current maintainer: Yu Zhai <me@zhaiyusci.net> License: LaTeX Project Public License, version 1.3c or later Maintenance status: maintained

Description

matchedsplit allows \left, \middle and \right constructions to cross manually chosen alignment rows. Each delimiter pair is measured independently, including nested pairs. The package provides:

• matchedsplit: an inner math alignment, with numbering supplied by its parent;
• matchedalign and matchedalign*: numbered and unnumbered display alignments;
• overridesplit and overridealign: opt-in replacements for the amsmath environments.

It does not choose line breaks automatically. Groups and inner environments are kept intact; cross-boundary pairing and side-effectful formula macros are outside the supported interface. See the manual for details.

Requirements

LaTeX dated 2020-10-01 or later, with amsmath, xcolor and l3keys2e. The minimum kernel date is required by the command-copy and hook interfaces. Older formats are rejected with an explicit error. Tested with pdfLaTeX, XeLaTeX and LuaLaTeX in TeX Live 2026, including kernel rollback to 2020-10-01. Rollback keeps installed package versions; complete older distributions have not been verified. No special fonts or shell escape are needed by the package itself, and it is not platform-specific.

Installation

Place matchedsplit.sty beside your document, or install it under tex/latex/matchedsplit/ in a personal TEXMF tree. Refresh the filename database if required by your installation. No docstrip extraction is needed.

\usepackage{matchedsplit}

To replace the native environments instead:

\usepackage[overridesplit,overridealign]{matchedsplit}

Example

\begin{matchedalign}
F &= \left( a+\frac{x}{y} \label{eq:first}\\
  &\quad +\frac{p}{q}\right)\label{eq:second}
\end{matchedalign}

Each row receives a number. For one number for the complete formula, put matchedsplit inside equation. Compile twice to resolve references. The complete example is numbered_example.tex.

Rainbow delimiters

Enable coloring globally with \usepackage[rainbow]{matchedsplit}, or locally with \begin{matchedalign}[rainbow]. Use [rainbow=false] to disable a global default for one environment. The same local options work on matchedsplit, matchedalign, and on the replaced split/align/align.

Use colors={blue,orange,teal} at either level to select a nonempty xcolor palette. The palette cycles by nesting depth; sibling pairs reuse their color. A pair's left/right/middle delimiters remain the same color across rows, while formula contents and equation numbers retain their own color. The colors key alone does not enable coloring. Groups and native inner environments retain their original behavior.

Documentation

Read matchedsplit.pdf. Rebuild it from the directory containing the package and documentation source:

pdflatex matchedsplit.tex
pdflatex matchedsplit.tex

The manual additionally uses standard documentation packages including geometry, Latin Modern, listings, booktabs, fancyhdr, xcolor and hyperref. Its mathematical examples are typeset by matchedsplit itself.

License and reporting bugs

Copyright (C) 2026 Yu Zhai.

This work may be distributed and/or modified under the conditions of the LaTeX Project Public License, either version 1.3c of this license or (at your option) any later version. The latest version is available at https://www.latex-project.org/lppl.txt.

This work has the LPPL maintenance status maintained. The Current Maintainer is Yu Zhai <me@zhaiyusci.net>. See MANIFEST.md for the files comprising the distribution and LICENSE for the license notice.

Please send bug reports with a minimal reproducing document, the engine and distribution version, and the relevant log to <me@zhaiyusci.net>.

Repository: https://github.com/zhaiyusci/matchedsplit

Issue tracker: https://github.com/zhaiyusci/matchedsplit/issues