index.js

'use strict';

module.exports = function sample_plugin(md) {
  function sample(state, startLine, endLine, silent) {
    var marker, len, params, nextLine, mem, token, markup,
        haveEndMarker = false,
        pos = state.bMarks[startLine] + state.tShift[startLine],
        max = state.eMarks[startLine];

    if (pos + 3 > max) { return false; }

    marker = state.src.charCodeAt(pos);

    if (marker !== 0xb4/* ´ */) {
      return false;
    }

    // scan marker length
    mem = pos;
    pos = state.skipChars(pos, marker);

    len = pos - mem;

    if (len < 3) { return false; }

    markup = state.src.slice(mem, pos);
    params = state.src.slice(pos, max);

    if (params.indexOf('`') >= 0) { return false; }

    // Since start is found, we can report success here in validation mode
    if (silent) { return true; }

    // search end of block
    nextLine = startLine;

    for (;;) {
      nextLine++;
      if (nextLine >= endLine) {
        // unclosed block should be autoclosed by end of document.
        // also block seems to be autoclosed by end of parent
        break;
      }

      pos = mem = state.bMarks[nextLine] + state.tShift[nextLine];
      max = state.eMarks[nextLine];

      if (pos < max && state.sCount[nextLine] < state.blkIndent) {
        // non-empty line with negative indent should stop the list:
        // - ```
        //  test
        break;
      }

      if (state.src.charCodeAt(pos) !== marker) { continue; }

      if (state.sCount[nextLine] - state.blkIndent >= 4) {
        // closing fence should be indented less than 4 spaces
        continue;
      }

      pos = state.skipChars(pos, marker);

      // closing sample fence must be at least as long as the opening one
      if (pos - mem < len) { continue; }

      // make sure tail has spaces only
      pos = state.skipSpaces(pos);

      if (pos < max) { continue; }

      haveEndMarker = true;
      // found!
      break;
    }

    // If a fence has heading spaces, they should be removed from its inner block
    len = state.sCount[startLine];

    state.line = nextLine + (haveEndMarker ? 1 : 0);

    token         = state.push('sample', 'samp', 0);
    token.info    = params;
    token.content = state.getLines(startLine + 1, nextLine, len, true);
    token.markup  = markup;
    token.map     = [ startLine, state.line ];

    return true;
  };

  md.block.ruler.before('fence', 'sample', sample, { alt: [ 'paragraph', 'reference', 'blockquote', 'list' ]})

  md.renderer.rules.sample = (tokens, idx, options, env, self) => {
    var token = tokens[idx]

    return '<pre><samp' + self.renderAttrs(token) + '>' + md.utils.escapeHtml(token.content) + '</samp></pre>\n'
  }
}