@observablehq/highlight.js/async-languages/bnf.js

Syntax highlighting with language autodetection.

/*
Language: Backus–Naur Form
Author: Oleg Efimov <efimovov@gmail.com>
*/

function(hljs){
  return {
    contains: [
      // Attribute
      {
        className: 'attribute',
        begin: /</, end: />/
      },
      // Specific
      {
        begin: /::=/,
        starts: {
          end: /$/,
          contains: [
            {
              begin: /</, end: />/
            },
            // Common
            hljs.C_LINE_COMMENT_MODE,
            hljs.C_BLOCK_COMMENT_MODE,
            hljs.APOS_STRING_MODE,
            hljs.QUOTE_STRING_MODE
          ]
        }
      }
    ]
  };
}
)