load "../logo/readline.lg
load "../logo/reader.lg
load "../logo/printer.lg
load "../logo/types.lg
load "../logo/env.lg
load "../logo/core.lg

to _read :str
output read_str :str
end

to eval_ast :ast :env
output case (obj_type :ast) [
  [[symbol]  env_get :env :ast]
  [[list]    obj_new "list    map [_eval ? :env] obj_val :ast]
  [[vector]  obj_new "vector  map [_eval ? :env] obj_val :ast]
  [[hashmap] obj_new "hashmap map [_eval ? :env] obj_val :ast]
  [else :ast]
]
end

to _eval :a_ast :a_env
localmake "ast :a_ast
localmake "env :a_env
forever [
  if (obj_type :ast) <> "list [output eval_ast :ast :env]
  if emptyp obj_val :ast [output :ast]
  localmake "a0 nth :ast 0
  case list obj_type :a0 obj_val :a0 [
    [[[symbol def!]]
      localmake "a1 nth :ast 1
      localmake "a2 nth :ast 2
      output env_set :env :a1 _eval :a2 :env ]

    [[[symbol let*]]
      localmake "a1 nth :ast 1
      localmake "letenv env_new :env [] []
      localmake "i 0
      while [:i < _count :a1] [
        ignore env_set :letenv nth :a1 :i _eval nth :a1 (:i + 1) :letenv
        make "i (:i + 2)
      ]
      make "env :letenv
      make "ast nth :ast 2 ]        ; TCO

    [[[symbol do]]
      localmake "i 1
      while [:i < ((_count :ast) - 1)] [
        ignore _eval nth :ast :i :env
        make "i (:i + 1)
      ]
      make "ast last obj_val :ast ] ; TCO

    [[[symbol if]]
      localmake "a1 nth :ast 1
      localmake "cond _eval :a1 :env
      case obj_type :cond [
        [[nil false] ifelse (_count :ast) > 3 [
                       make "ast nth :ast 3  ; TCO
                     ] [
                       output nil_new
                     ]]
        [else        make "ast nth :ast 2]   ; TCO
      ]]

    [[[symbol fn*]]
      output fn_new nth :ast 1 :env nth :ast 2 ]

    [else
      localmake "el eval_ast :ast :env
      localmake "f nth :el 0
      case obj_type :f [
        [[nativefn]
          output apply obj_val :f butfirst obj_val :el ]
        [[fn]
          make "env env_new fn_env :f fn_args :f rest :el
          make "ast fn_body :f ]  ; TCO
        [else
          (throw "error [Wrong type for apply])]
      ] ]
  ]
]
end

to _print :exp
output pr_str :exp "true
end

to re :str
output _eval _read :str :repl_env
end

to rep :str
output _print re :str
end

to repl
localmake "running "true
while [:running] [
  localmake "line readline word "user> :space_char
  ifelse :line=[] [
    print "
    make "running "false
  ] [
    if not emptyp :line [
      catch "error [print rep :line]
      localmake "exception error
      if not emptyp :exception [
        (print "Error: first butfirst :exception)
      ]
    ]
  ]
]
end

make "repl_env env_new [] [] []
foreach :core_ns [
  ignore env_set :repl_env first ? first butfirst ?
]
; core.mal: defined using the language itself
ignore re "|(def! not (fn* (a) (if a false true)))|
repl
bye