; repl.neb
; by mryouse
;
; a REPL for neb, written in neb

(def _history_ (list))

(func history ()
    _history_)

(func !! ()
    (def cmd (first (list-reverse (history))))
    (print (->string cmd))
    (eval (parse-neb cmd)))

(func save-repl (filename :string)
    (def fil (open-write filename))
    (write (concat (join (history) "\n") "\n") fil)
    (close fil))

(func prompt (nxt)
    (concat "#" (->string nxt) "> "))

(func repl ()
    (print "### neb :)(: IN NEB!")
    (print "version: < 0")

    (def next-cmd-num 1)

    (func get-non-empty-input ()
        (def tmp "")
        (while (eq? "" tmp)
            (redef tmp (strip (read-line (prompt next-cmd-num)))))
        tmp)

    (func print-result (res)
        ;(def calc res)
        (print (concat "=> "
            (if (eq? :string (typeof res))
                (raw res)
                (->string res)))))

    ; this is the actual loop part
    (while #true
        (def this-cmd (get-non-empty-input))
        (def panicked #false) ; we may not need this two-step if there's a :panic type
        (def evaluated
            (try
                ;(eval (first (parse-neb this-cmd)))
                (quote (first (parse-neb this-cmd)))
                ;(quote (map eval (parse-neb this-cmd)))
                ;(parse-neb this-cmd)
                (block
                    (redef panicked #true)
                    _panic_)))

        ;(print evaluated)

        (if panicked
            (print (concat "panic! " evaluated))
            (block
                (print-result 'evaluated)
                (redef next-cmd-num (+ 1 next-cmd-num))
                (redef _history_ (append _history_ this-cmd))))))

(repl)