 # deal with them.
 re::add_implicit_parentheses: ->
   stack: [0]
-  this.scan_tokens (prev, token, post, i) =>
+  @scan_tokens (prev, token, post, i) =>
     stack.push(0) if token[0] is 'INDENT'
     if token[0] is 'OUTDENT'
       last: stack.pop()

          # Unexpected close, insert correct close, adding to the debt.
          debt[mtag] += 1
          val: if mtag is 'INDENT' then match[1] else INVERSES[mtag]
          this.tokens.splice(i, 0, [INVERSES[mtag], val])
          return 1
    else
      return 1

  stack: []
  debt:  {}
  (debt[key]: 0) for key, val of INVERSES
  @scan_tokens (prev, token, post, i) =>
    tag: token[0]
    inv: INVERSES[token[0]]
    # Push openers onto the stack.
