Backtrack

Backtrack is a simple and performant Typst library that determines the current compiler version and provides an API for comparing, displaying, and observing versions.

Unlike the built-in version API which is only available on Typst 0.9.0+, Backtrack works on any* Typst version. It uses the built-in API when available so that it'll continue to work on all future Typst versions without modification.

Additionally, it:

• doesn't noticeably impact compilation time. All version checks are extremely simple, and newer versions are checked first to avoid overhead from supporting old versions.
• is automatically tested on every supported Typst version to ensure reliability.
• can be downloaded and installed manually in addition to being available as a package.

Example

#import "@preview/backtrack:1.0.0": current-version, versions

You are using Typst #current-version.displayable!
#{
  if current-version.cmpable <= versions.v2023-03-28.cmpable [
    That is ancient.
  ] else if current-version.cmpable < versions.v0-5-0.cmpable [
    That is old.
  ] else [
    That is modern.
  ]
}

Installation

There are two ways to install the library:

• Use the package on Typst 0.6.0+. This is as simple as adding the following line to your document:

  #import "@preview/backtrack:1.0.0"

• Download and install the library manually:
  1. Download and extract the latest release.
  2. Rename src/lib.typ to src/backtrack.typ.
  3. Move/copy COPYING into src/.
  4. Rename the src/ directory to backtrack/.
  5. Move/copy the newly-renamed backtrack/ directory into your project.
  6. Add the following line to your document:

     #import "[path/to/]backtrack/backtrack.typ"

Documentation

See DOCS.md. It's quite short. 😀

Version Support

Backtrack compiles on and can detect these versions:

Version	Status	Notes
0.6.0+	✅	Also available as a package
March 28, 2023–0.5.0	✅
March 21, 2023	✅	Initial public/standalone Typst release
February 25, 2023	🟡	Detects as February 15, 2023
February 12–15, 2023	✅
February 2, 2023	🟡	Detects as January 30, 2023
January 30, 2023	✅

The partially-supported versions may be possible to detect, but they're tricky since most of their changes are content-related. Content values were opaque up until the March 21, 2023 release, making it difficult to automatically check for the presence of these changes.

Copying

Copyright © 2023 Luke Chambers

Backtrack is licensed under the Apache License, Version 2.0. You can find a copy of the license in COPYING or online at https://www.apache.org/licenses/LICENSE-2.0.