anchor.diff:  
   
   //- Permalink rendering
  +    id - [string] permalink ID used for link anchor
   
   mixin permalink(id)
       if id
  
positive.code: 
  
  //- Icon
  
  mixin icon(name, size)
      +svg("icons", name, size || 20).o-icon&attributes(attributes)
  
  
  //- Pro/Con/Neutral icon
  
  mixin procon(icon)
      - colors = { pro: "green", con: "red" }
  
negative.code: 
  
  //- SVG from map
      file   - [string] SVG file name in /assets/img/
      name   - [string] SVG symbol id
      width  - [integer] width in px
      height - [integer] height in px (default: same as width)
  
  mixin svg(file, name, width, height)
      svg(aria-hidden="true" viewBox="0 0 #{width} #{height || width}" width=width height=(height || width))&attributes(attributes)
  