anchor.diff:  
   (is (parse-template-string "the content of foo is {{include \"foo\"}}")
       (att-progn
  -     (att-output (att-string ""))
        (att-output
         (att-string "the content of foo is "))
        (att-progn
  
positive.code: (is (parse-template-string "{{if cond}}aaa{{else}}bbb{{endif}}")
      (att-progn
       (att-output (att-string ""))
       (att-if (att-variable 'cond)
               (att-progn (att-output (att-string "aaa")))
               (att-progn (att-output (att-string "bbb"))))
       (att-output (att-string "")))
  
negative.code:      (att-output (att-string ""))
       (att-loop (att-constant '(1 2 3 4 5 6 7 8 9 10))
                           (att-progn (att-output (att-string "<li>item"))
                                      (att-output (att-variable 'arrows.lexer.default::i))
                                      (att-output (att-string "</li>")))
                           (att-variable 'arrows.lexer.default::i))
       (att-output (att-string "")))
      "repeat with index"
      :test #'att-equal)
  