The `whenenv` LaTeX package provides a minimal and elegant way to define conditional content blocks. It is built on top of `etoolbox` and uses the `\NewEnviron` mechanism from `environ` to define environments whose inclusion is toggled by named switches.
It is especially useful in documents that need selective inclusion based on output format, target audience, or publication state.
- Define toggleable environments with `\whenEnv{envname}`
- Enable or disable environment content with `\whenEnable{envname}` or `\whenDisable{envname}`
- Environments are idempotently defined (safe for multiple declarations)
- Environments render their contents only when enabled
There are many ways to do conditional text in LaTeX.
The comment.sty package is one. That package can not be nested and is fragile.
The etoolbox.sty is too low level. It provides basic machinary for conditioning but is not easy to read.
whenenv.sty uses etoolbox.sty to accomplish equivalent of comment.sty. It could be easily enhanced to fully replace/obsolete comment.sty.
To use `whenenv.sty` in your project:
- Place `whenenv.sty` in your LaTeX source directory.
- Include it in your preamble:
\usepackage{whenenv}
- **Declare a toggled environment**
\whenEnv{whenHtml} - **Control inclusion**
\whenEnable{whenHtml} \whenDisable{whenHtml}
- **Wrap content**
\begin{whenHtml} This text is shown only when `whenHtml` is enabled. \end{whenHtml}
Calling `\whenEnv{foo}` multiple times has no effect after the first. The macro tracks previously defined environments internally.
- Works across `\input` and modular files
- Cleaner alternative to `comment.sty`
- Declarative and toggle-based
- Useful for literate programming and multi-output publishing
This package is released under the LaTeX Project Public License v1.3c or later. This is a Libre-Halaal polyexistential.
This packages is designed by Mohsen Banan. But, implemented by ChatGpt. The design specification is in file:./design-gpt.transcript.
Most of the documentation and test file was also created using AI.