mal/step6_file.mal

   1 (load-file "../mal/env.mal")
   2 (load-file "../mal/core.mal")
   3
   4 ;; read
   5 (def! READ (fn* [strng]
   6   (read-string strng)))
   7
   8
   9 ;; eval
  10 (def! eval-ast (fn* [ast env] (do
  11   ;;(do (prn "eval-ast" ast "/" (keys env)) )
  12   (cond
  13     (symbol? ast) (env-get env ast)
  14
  15     (list? ast)   (map (fn* [exp] (EVAL exp env)) ast)
  16
  17     (vector? ast) (apply vector (map (fn* [exp] (EVAL exp env)) ast))
  18
  19     (map? ast)    (apply hash-map
  20                       (apply concat
  21                         (map (fn* [k] [k (EVAL (get ast k) env)])
  22                              (keys ast))))
  23
  24     "else"        ast))))
  25
  26 (def! LET (fn* [env args]
  27   (if (> (count args) 0)
  28     (do
  29       (env-set env (nth args 0) (EVAL (nth args 1) env))
  30       (LET env (rest (rest args)))))))
  31
  32 (def! EVAL (fn* [ast env] (do
  33   ;;(do (prn "EVAL" ast "/" (keys @env)) )
  34   (if (not (list? ast))
  35     (eval-ast ast env)
  36
  37     ;; apply list
  38     (let* [a0 (first ast)]
  39       (cond
  40         (= 'def! a0)
  41         (env-set env (nth ast 1) (EVAL (nth ast 2) env))
  42
  43         (= 'let* a0)
  44         (let* [let-env (new-env env)]
  45           (do
  46             (LET let-env (nth ast 1))
  47             (EVAL (nth ast 2) let-env)))
  48
  49         (= 'do a0)
  50         (let* [el (eval-ast (rest ast) env)]
  51           (nth el (- (count el) 1)))
  52
  53         (= 'if a0)
  54         (let* [cond (EVAL (nth ast 1) env)]
  55           (if (or (= cond nil) (= cond false))
  56             (if (> (count ast) 3)
  57               (EVAL (nth ast 3) env)
  58               nil)
  59             (EVAL (nth ast 2) env)))
  60
  61         (= 'fn* a0)
  62         (fn* [& args]
  63           (EVAL (nth ast 2) (new-env env (nth ast 1) args)))
  64
  65         "else"
  66         (let* [el (eval-ast ast env)
  67               f (first el)
  68               args (rest el)]
  69           (apply f args))))))))
  70
  71
  72 ;; print
  73 (def! PRINT (fn* [exp] (pr-str exp)))
  74
  75 ;; repl
  76 (def! repl-env (new-env))
  77 (def! rep (fn* [strng]
  78   (PRINT (EVAL (READ strng) repl-env))))
  79
  80 ;; core.mal: defined directly using mal
  81 (map (fn* [data] (env-set repl-env (nth data 0) (nth data 1))) core_ns)
  82 (env-set repl-env 'eval (fn* [ast] (EVAL ast repl-env)))
  83 (env-set repl-env '*ARGV* (rest *ARGV*))
  84
  85 ;; core.mal: defined using the new language itself
  86 (rep "(def! not (fn* [a] (if a false true)))")
  87 (rep "(def! load-file (fn* (f) (eval (read-string (str \"(do \" (slurp f) \")\")))))")
  88
  89 ;; repl loop
  90 (def! repl-loop (fn* []
  91   (let* [line (readline "mal-user> ")]
  92     (if line
  93       (do
  94         (if (not (= "" line))
  95           (try*
  96             (println (rep line))
  97             (catch* exc
  98               (println "Uncaught exception:" exc))))
  99         (repl-loop))))))
 100
 101 (def! -main (fn* [& args]
 102   (if (> (count args) 0)
 103     (rep (str "(load-file \"" (first args) "\")"))
 104     (repl-loop))))
 105 (apply -main *ARGV*)