Writing is notoriously hard, even for the best writers, and it's not for lack of good advice — a tremendous amount of knowledge about the craft is strewn across usage guides, dictionaries, technical manuals, essays, pamphlets, websites, and the hearts and minds of great authors and editors. But poring over Strunk & White hardly makes one a better writer — it turns you into neither Strunk nor White. And nobody has the capacity to apply all the advice from Garner’s Modern English Usage, an 1100-page usage guide, to everything they write. In fact, the whole notion that one becomes a better writer by reading advice on writing rests on untenable assumptions about learning and memory. The traditional formats of knowledge about writing are thus essentially inert, waiting to be transformed.

We devised a simple solution: proselint, a linter for English prose. A linter is a computer program that, akin to a spell checker, scans through a file and detects issues — like how a real lint roller helps you get unwanted lint off of your shirt.

proselint places the world's greatest writers and editors by your side, where they whisper suggestions on how to improve your prose. You’ll be guided by advice inspired by Bryan Garner, David Foster Wallace, Chuck Palahniuk, Steve Pinker, Mary Norris, Mark Twain, Elmore Leonard, George Orwell, Matthew Butterick, William Strunk, Elwyn White, Philip Corbett, Ernest Gowers, and the editorial staff of the world’s finest literary magazines and newspapers, among others. Our goal is to aggregate knowledge about best practices in writing and to make that knowledge immediately accessible to all authors in the form of a linter for prose; all in a neat command-line utility that you can integrate into other tools, scripts, and workflows.

To get this up and running, install it using pip:

pip install proselint

sudo dnf install proselint

sudo apt install python3-proselint

sudo add-apt-repository universe
sudo apt install python3-proselint

proselint is available on:

• A demo editor
• Sublime Text
• Atom Editor (thanks to Clay Miller).
• Emacs via Flycheck or via Flymake
• Vim via ALE or Syntastic (thanks to @lcd047, @Carreau, and Daniel M. Capella)
• Neovim via null-ls (null-ls has diagnostics and code actions for proselint)
• Phabricator's arc CLI (thanks to Jeff Verkoeyen)
• Danger (thanks to David Grandinetti and Orta Therox)
• Visual Studio Code (thanks to Patryk Peszko)
• coala (thanks to the coala Development Group)
• IntelliJ (by Victor Kropp)
• pre-commit (by Andy Airey)
• Statick
• MegaLinter

Suppose you have a document text.md with the following text:

John is very unique.

You can run proselint over the document using the command line:

proselint text.md

This prints a list of suggestions to stdout, one per line. Each suggestion has the form:

text.md:<line>:<column>: <check_name> <message>

For example,

text.md:0:10: wallace.uncomparables Comparison of an uncomparable: 'unique' cannot be compared.

The command-line utility can also print suggestions in JSON using the --json flag. In this case, the output is considerably richer:

{
  // Type of check that output this suggestion.
  check: "wallace.uncomparables",

  // Message to describe the suggestion.
  message: "Comparison of an uncomparable: 'unique' cannot be compared.",

  // The person or organization giving the suggestion.
  source: "David Foster Wallace"

  // URL pointing to the source material.
  source_url: "http://www.telegraph.co.uk/a/9715551"

  // Line where the error starts.
  line: 0,

  // Column where the error starts.
  column: 10,

  // Index in the text where the error starts.
  start: 10,

  // Index in the text where the error ends.
  end: 21,

  // length from start -> end
  extent: 11,

  // How important is this? Can be "suggestion", "warning", or "error".
  severity: "warning",

  // Possible replacements.
  replacements: [
    {
      value: "unique"
    }
  ]
}

To run the linter as part of another Python program, you can use the lint function in proselint.tools:

import proselint

suggestions = proselint.tools.lint("This sentence is very unique")

This will return a list of suggestions:

[('weasel_words.very', "Substitute 'damn' every time you're inclined to write 'very;' your editor will delete it and the writing will be just as it should be.", 0, 17, 17, 22, 5, 'warning', None), ('uncomparables.misc', "Comparison of an uncomparable: 'very unique.' is not comparable.", 0, 17, 17, 29, 12, 'warning', None)]

You can disable any of the checks by modifying $XDG_CONFIG_HOME/proselint/config.json. If $XDG_CONFIG_HOME is not set or empty, ~/.config/proselint/config.json will be used. Additionally, for compatibility reasons, the legacy configurations ~/.proselintrc and $XDG_CONFIG_HOME/proselint/config will be checked if $XDG_CONFIG_HOME/proselint/config.json does not exist.

{
  "checks": {
    "typography.diacritical_marks": false
  }
}

Interested in contributing to proselint? Great — there are plenty of ways you can help. Read more on our website, where we describe how you can help us build proselint into the greatest writing tool in the world.

• Issue Tracker
• Source Code

If you run into a problem, please open an issue in or send an email to hello@amperser.com.

Automated tests are included in the proselint/tests directory. To run these tests locally, you can use ./utils.

The project is licensed under the BSD license.