#pest-parser #parser #html-parser #file-format #pest #css-class #element

bin+lib bem

Parser for the BEM file format (Block, Element, Modifier)

10 releases

0.2.7 Aug 15, 2023
0.2.6 Aug 15, 2023
0.1.1 Aug 14, 2023

#1136 in Parser implementations

Download history 5/week @ 2024-03-15 3/week @ 2024-03-29 2/week @ 2024-04-05 1/week @ 2024-04-19

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MIT license

590 lines

BEM Parser

A Rust-based parser for the BEM (Block Element Modifier) file format, utilizing the Pest parsing library.

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This parser provides functionality to parse BEM notations, primarily used in CSS methodologies for naming classes in HTML. With this parser, you can interpret and work with BEM notations programmatically in Rust.


  • Parse BEM blocks, elements, and modifiers.
  • Support for dashes in block and element names.
  • Support for enclosing modifiers in square brackets and separating with commas.
  • Robust error handling with detailed parsing error messages.
  • Lightweight and efficient parsing using Pest.

Getting Started


Ensure you have Rust and Cargo installed:

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh


Here's a simple example to parse a BEM formatted string:

use bem::parse;

let input = "block[mod1,mod2]\nelement1\nelement2[mod3]";
let bem_block = parse(input).unwrap();

// You can now access `bem_block.name`, `bem_block.modifiers`, and `bem_block.elements`.

Error Handling

The parse function returns a Result<BEMBlock, String>, allowing you to handle parsing errors explicitly. Here's an example:

let input = "block[mod1,mod2]\nelement1\nelement2[mod3]";
match parse(input) {
    Ok(bem_block) => {
        // Process the parsed block
    Err(error) => {
        println!("Failed to parse BEM content: {}", error);


Find the documentation for your installed version at https://docs.rs/bem/VERSION/bem/, replacing VERSION with your installed version number.


Feel free to open issues or pull requests if you have suggestions, improvements, or fixes.


MIT License. See LICENSE for details.


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