Proof of concept PHP-style templating mode for Janet

jamplate.janet

(def- opener "<?janet")
(def- closer "?>")
(def- file ~{:main (some (+ :code :text))
             :text '(to (+ ,opener -1))
             :code (/ :code* ,parse-all)
             :code* (* ,opener '(to ,closer) ,closer)})

(defn template-string
  [s]
  (def out @"")
  (def env (make-env))
  (put env :out out)
  (def mch (peg/match file s))
  (each v mch
    (if (array? v)
      (do (def fib (fiber/new (fn [] ((compile v env))) :a))
          (fiber/setenv fib env)
          (resume fib))
      (buffer/push out v)))
  out)

# example
(print (template-string ```
                        before
                        <?janet (def bye "bye") (prin "hi") ?>
                        middle
                        <?janet (prin bye) ?>
                        after
                        ```))