Harper Grammar Checker

Harper is a next-generation grammar checker designed for code. It serves as an alternative to tools like Grammarly by catching stylistic errors, complex grammatical issues, and layout-related problems.

Key features include:

• Broad Language Support: Works with almost all common programming languages and various markup formats.
• On-device Execution: Runs locally on your machine, ensuring low memory usage and millisecond-level feedback.
• API Documentation Protection: Helps ensure that comments in languages like Rust, Java, or JavaScript remain grammatically correct, preventing poor search engine ranking or quality issues in your public API documentation.

Weir is an expression language used to define linguistic rules and conventions for Harper to enforce. It allows individuals and organizations to implement style guides (e.g., Oxford comma usage, capitalization rules, or brand name enforcement).

A typical Weir rule consists of an expression defining the pattern to match, followed by metadata describing the error and the correction. You can experiment with rules in the Weir studio.

expr main [(G [Suite, Suit]), (Google Apps for Work)]

let message "Use the updated brand."
let description "`G Suite` or `Google Apps for Work` is now called `Google Workspace`"
let kind "Miscellaneous"
let becomes "Google Workspace"

harper-comments is a crate designed to help Harper identify and extract comments from various programming languages. It functions primarily as a wrapper around tree-sitter to locate comments across a wide range of languages.

Additionally, it provides purpose-built parsers for structured comments in specific languages (such as Go). These specialized parsers are accessible via the CommentParser and are enabled automatically through it.

The website code is organized into several key directories within the repository:

Harper is designed as a privacy-focused, high-performance grammar checker for Obsidian users. Key characteristics include:

• Privacy: Runs entirely offline inside Obsidian. Your data is not sent to centralized servers.
• Code Awareness: Explicitly ignores the contents of code fences and inline code blocks to prevent false positives in technical writing.
• Performance: Faster than network-based alternatives (like Grammarly or LanguageTool) because it eliminates network latency by running on-device.
• Real-Time Checking: Provides immediate feedback as you type.

The harper-dictionary-wordlist package provides utility methods designed to facilitate loading external wordlists into Harper dictionaries. This is useful for extending Harper's vocabulary with custom or domain-specific terms.

For detailed API documentation and specific method signatures, refer to the generated cargo doc for this crate.

harper-wasm is the WebAssembly (WASM) compiled version of the Harper grammar checker. It is designed to allow Harper's grammar checking capabilities to run in web environments and browser-based applications.

The current API implementation is optimized to support the requirements of the Write with Harper web demo and the Obsidian plugin.

Because the extension is powered by harper-ls, it inherits several advanced features:

• Dictionaries: Use custom dictionaries for linting.
• Code Actions: Automatically fix or suggest improvements for identified issues.
• Ignore Comments: Use comments to instruct Harper to ignore specific sections of text.