(load-file "../mal/env.mal")

;; read

(def! READ (fn* [strng]

(read-string strng)))

;; eval

(def! eval-ast (fn* [ast env] (do

;;(do (prn "eval-ast" ast "/" (keys env)) )

(cond

(symbol? ast) (env-get env ast)

(list? ast) (map (fn* [exp] (EVAL exp env)) ast)

(vector? ast) (apply vector (map (fn* [exp] (EVAL exp env)) ast))

(map? ast) (apply hash-map

(apply concat

(map (fn* [k] [k (EVAL (get ast k) env)])

(keys ast))))

"else" ast))))

(def! LET (fn* [env args]

(if (> (count args) 0)

(do

(env-set env (nth args 0) (EVAL (nth args 1) env))

(LET env (rest (rest args)))))))

(def! EVAL (fn* [ast env] (do

;;(do (prn "EVAL" ast "/" (keys @env)) )

(if (not (list? ast))

(eval-ast ast env)

;; apply list

(let* [a0 (first ast)]

(cond

(nil? a0)

ast

(= 'def! a0)

(env-set env (nth ast 1) (EVAL (nth ast 2) env))

(= 'let* a0)

(let* [let-env (new-env env)]

(do

(LET let-env (nth ast 1))

(EVAL (nth ast 2) let-env)))

"else"

(let* [el (eval-ast ast env)

f (first el)

args (rest el)]

(apply f args))))))))

;; print

(def! PRINT (fn* [exp] (pr-str exp)))

;; repl

(def! repl-env (new-env))

(def! rep (fn* [strng]

(PRINT (EVAL (READ strng) repl-env))))

(env-set repl-env "+" +)

(env-set repl-env "-" -)

(env-set repl-env "*" *)

(env-set repl-env "/" /)

;; repl loop

(def! repl-loop (fn* []

(let* [line (readline "mal-user> ")]

(if line

(do

(if (not (= "" line))

(try*

(println (rep line))

(catch* exc

(println "Uncaught exception:" exc))))

(repl-loop))))))

(def! -main (fn* [& args]

(repl-loop)))

(-main)