code: function CreateHtmlReservedCharsGrammar(myna) 
  {
      let m = myna;
      
      let g = new function() 
      {
          let escapeChars = '&<>"\'';        
          this.specialChar = m.char(escapeChars).ast;
          this.plainText = m.notChar(escapeChars).oneOrMore.ast;
          this.text = m.choice(this.specialChar, this.plainText).zeroOrMore;
      }
  
      // Register the grammar, providing a name and the default parse rule
      return m.registerGrammar('html_reserved_chars', g, g.text);
  }
docs: Define a grammar for common HTML reserved chars. Those are characters like <, >, and & that should be be replaced by an HTML entity to be displayed correctly.