mirror of
https://github.com/kanaka/mal.git
synced 2024-10-26 22:28:26 +03:00
make envs mutable
This commit is contained in:
parent
3224c1b856
commit
e160b83391
@ -24,7 +24,7 @@ val coreList = [
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(* N.B. adds extra newline at end *)
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fun slurp lines strm = case TextIO.inputLine strm of
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SOME l => slurp (l::lines) strm
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| NONE => rev lines
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| NONE => (TextIO.closeIn strm; rev lines)
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fun malPrint s = (
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TextIO.print (s ^ "\n");
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@ -107,9 +107,8 @@ val coreAtom = [
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| _ => raise NotApplicable "'reset!' requires an atom argument"),
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SYMBOL "swap!",
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FN6 (fn e => (fn (ATOM a::(FN f)::args) => let val x = f ((!a)::args) in (a := x; (e, x)) end
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| (ATOM a::(FN4 f)::args) => let val x = f e ((!a)::args) in (a := x; (e, x)) end
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| (ATOM a::(FN6 f)::args) => let val (e',x) = f e ((!a)::args) in (a := x; (e', x)) end
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CLOSURE (fn e => (fn (ATOM a::(FN f)::args) => let val x = f ((!a)::args) in (a := x; x) end
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| (ATOM a::(CLOSURE f)::args) => let val x = f e ((!a)::args) in (a := x; x) end
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| _ => raise NotApplicable "'reset!' requires an atom argument"))
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]
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@ -1,5 +1,14 @@
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fun def s v (ENV d) = (s, v) :: (d |> List.filter (not o eq s o #1)) |> ENV
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fun set s v (NS d) = d := (s, v) :: (!d |> List.filter (not o eq s o #1))
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fun lookup (ENV d) s = d |> List.find (eq s o #1) |> Option.map #2
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fun get (NS d) s = !d |> List.find (eq s o #1) |> Option.map #2
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fun wrap (ENV outer) (ENV inner) = ENV (inner @ outer)
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fun def s v (ENV ns) = set s v ns
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| def s v (INNER (ns, _)) = set s v ns
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fun lookup (ENV ns) s = get ns s
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| lookup (INNER (ns, outer)) s = optOrElse (get ns s) (fn () => lookup outer s)
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fun wrap outer (ENV ns) = INNER (ns, outer)
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| wrap outer (INNER (ns, inner)) = INNER (ns, wrap outer inner)
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fun inside outer = INNER (NS (ref []), outer)
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@ -7,8 +7,7 @@ fun prStr NIL = "nil"
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| prStr (STRING s) = s
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| prStr (LIST l) = "(" ^ (String.concatWith " " (map prStr l)) ^ ")" (* N.B. not tail recursive *)
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| prStr (FN _) = "#<function>"
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| prStr (FN4 _) = "#<function>"
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| prStr (FN6 _) = "#<function>"
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| prStr (CLOSURE _) = "#<function>"
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fun prReadableStr (STRING s) = "\"" ^ (malEscape s) ^ "\""
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| prReadableStr (ATOM x) = "(atom " ^ (prReadableStr (!x)) ^ ")"
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@ -40,7 +40,7 @@ fun malMinus (INT b, INT a) = INT (a - b)
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fun malDiv (INT b, INT a) = INT (a div b)
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| malDiv _ = raise NotApplicable "can only divide integers"
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val initEnv = ENV [
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val initEnv = ENV (NS (ref [
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("+", FN (foldl malPlus (INT 0))),
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("*", FN (foldl malTimes (INT 1))),
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("-", FN (
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@ -53,7 +53,7 @@ val initEnv = ENV [
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| x::xs => foldr malDiv x xs
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| _ => raise NotApplicable "'/' requires at least one argument"
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))
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]
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]))
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fun repl () =
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let open TextIO
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@ -6,25 +6,23 @@ fun read s =
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fun eval e (LIST (SYMBOL "def!"::args)) = evalDef e args
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| eval e (LIST (SYMBOL "let*"::args)) = evalLet e args
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| eval e (LIST (a::args)) = (e, evalApply e (eval' e a) args)
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| eval e (SYMBOL s) = (e, evalSymbol e s)
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| eval e ast = (e, ast)
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| eval e (LIST (a::args)) = evalApply e (eval e a) args
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| eval e (SYMBOL s) = evalSymbol e s
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| eval e ast = ast
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and eval' e ast = (#2 o eval e) ast
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and evalDef e [SYMBOL s, ast] = let val v = eval' e ast in (def s v e, v) end
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and evalDef e [SYMBOL s, ast] = let val v = eval e ast in (def s v e; v) end
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| evalDef _ _ = raise NotApplicable "def! needs a symbol and a form to evaluate"
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and evalLet e [LIST bs, ast] = (e, eval' (bind bs e) ast)
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and evalLet e [LIST bs, ast] = eval (bind bs (inside e)) ast
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| evalLet _ _ = raise NotApplicable "let* needs a list of bindings and a form to evaluate"
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and evalApply e (FN f) args = f (map (eval' e) args)
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and evalApply e (FN f) args = f (map (eval e) args)
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| evalApply _ a args = raise NotApplicable (prStr a ^ " is not applicable on " ^ prStr (LIST args))
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and evalSymbol e s = valOrElse (lookup e s)
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(fn _ => raise NotDefined ("symbol '" ^ s ^ "' not found"))
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and bind (SYMBOL s::v::rest) e = def s (eval' e v) e |> bind rest
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and bind (SYMBOL s::v::rest) e = (def s (eval e v) e; bind rest e)
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| bind [] e = e
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| bind _ _ = raise NotApplicable "bindings must be a list of symbol/form pairs"
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@ -32,11 +30,11 @@ fun print f =
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prStr f
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fun rep e s =
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s |> read |> eval e |> (fn (e, v) => (e, print v))
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handle Nothing => (e, "")
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| SyntaxError msg => (e, "SYNTAX ERROR: " ^ msg)
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| NotApplicable msg => (e, "CANNOT APPLY: " ^ msg)
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| NotDefined msg => (e, "NOT DEFINED: " ^ msg)
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s |> read |> eval e |> print
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handle Nothing => ""
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| SyntaxError msg => "SYNTAX ERROR: " ^ msg
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| NotApplicable msg => "CANNOT APPLY: " ^ msg
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| NotDefined msg => "NOT DEFINED: " ^ msg
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fun malPlus (INT a, INT b) = INT (a + b)
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| malPlus _ = raise NotApplicable "can only add integers"
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@ -47,7 +45,7 @@ fun malMinus (INT b, INT a) = INT (a - b)
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fun malDiv (INT b, INT a) = INT (a div b)
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| malDiv _ = raise NotApplicable "can only divide integers"
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val initEnv = ENV [] |> bind [
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val initEnv = ENV (NS (ref [])) |> bind [
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SYMBOL "+",
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FN (foldl malPlus (INT 0)),
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SYMBOL "*",
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@ -68,10 +66,10 @@ fun repl e =
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print("user> ");
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case inputLine(stdIn) of
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SOME(line) =>
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let val (e', s) = rep e line
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let val s = rep e line
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val _ = print(s ^ "\n")
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in
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repl e'
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repl e
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end
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| NONE => ()
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) end
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@ -2,40 +2,38 @@ fun read s =
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readStr s
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fun eval e (LIST (SYMBOL "def!"::args)) = evalDef e args
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| eval e (LIST (SYMBOL "let*"::args)) = evalLet e args
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| eval e (LIST (SYMBOL "do"::args)) = evalDo e args
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| eval e (LIST (SYMBOL "if"::args)) = evalIf e args
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| eval e (LIST (SYMBOL "let*"::args)) = (e, evalLet e args)
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| eval e (LIST (SYMBOL "fn*"::args)) = (e, evalFn e args)
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| eval e (LIST (a::args)) = (e, evalApply e (eval' e a) args)
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| eval e (SYMBOL s) = (e, evalSymbol e s)
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| eval e ast = (e, ast)
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| eval e (LIST (SYMBOL "fn*"::args)) = evalFn e args
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| eval e (LIST (a::args)) = evalApply e (eval e a) args
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| eval e (SYMBOL s) = evalSymbol e s
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| eval e ast = ast
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and eval' e ast = (#2 o eval e) ast
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and evalDef e [SYMBOL s, ast] = let val v = eval' e ast in (def s v e, v) end
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and evalDef e [SYMBOL s, ast] = let val v = eval e ast in (def s v e; v) end
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| evalDef _ _ = raise NotApplicable "def! needs a symbol and a form to evaluate"
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and evalLet e [LIST bs, ast] = eval' (bind bs e) ast
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and evalLet e [LIST bs, ast] = eval (bind bs (inside e)) ast
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| evalLet _ _ = raise NotApplicable "let* needs a list of bindings and a form to evaluate"
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and evalDo e (x::xs) = foldl (fn (x, (e,_)) => eval e x) (eval e x) xs
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and evalDo e (x::xs) = foldl (fn (x, _) => eval e x) (eval e x) xs
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| evalDo _ _ = raise NotApplicable "do needs at least one argument"
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and evalIf e [c,a,b] = eval e c |> (fn (e,c) => eval e (if truthy c then a else b))
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and evalIf e [c,a,b] = if truthy (eval e c) then eval e a else eval e b
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| evalIf e [c,a] = evalIf e [c,a,NIL]
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| evalIf _ _ = raise NotApplicable "if needs two or three arguments"
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and evalFn c [(LIST binds),body] = FN4 (fn (e) => fn (exprs) => eval' (bind (interleave binds exprs) (wrap e c)) body)
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and evalFn c [(LIST binds),body] = CLOSURE (fn (e) => fn (exprs) => eval (bind (interleave binds exprs) (inside (wrap e c))) body)
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| evalFn _ _ = raise NotApplicable "fn* needs a list of bindings and a body"
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and evalApply e (FN4 (f)) args = f e (map (eval' e) args)
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| evalApply e (FN f) args = f (map (eval' e) args)
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and evalApply e (CLOSURE (f)) args = f e (map (eval e) args)
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| evalApply e (FN f) args = f (map (eval e) args)
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| evalApply _ x args = raise NotApplicable (prStr x ^ " is not applicable on " ^ prStr (LIST args))
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and evalSymbol e s = valOrElse (lookup e s)
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(fn _ => raise NotDefined ("symbol '" ^ s ^ "' not found"))
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and bind (SYMBOL s::v::rest) e = def s (eval' e v) e |> bind rest
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and bind (SYMBOL s::v::rest) e = (def s (eval e v) e; bind rest e)
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| bind [] e = e
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| bind _ _ = raise NotApplicable "bindings must be a list of symbol/form pairs"
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@ -43,13 +41,13 @@ fun print f =
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prStr f
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fun rep e s =
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s |> read |> eval e |> (fn (e, v) => (e, print v))
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handle Nothing => (e, "")
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| SyntaxError msg => (e, "SYNTAX ERROR: " ^ msg)
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| NotApplicable msg => (e, "CANNOT APPLY: " ^ msg)
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| NotDefined msg => (e, "NOT DEFINED: " ^ msg)
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s |> read |> eval e |> print
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handle Nothing => ""
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| SyntaxError msg => "SYNTAX ERROR: " ^ msg
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| NotApplicable msg => "CANNOT APPLY: " ^ msg
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| NotDefined msg => "NOT DEFINED: " ^ msg
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val initEnv = ENV [] |> bind coreNs
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val initEnv = ENV (NS (ref [])) |> bind coreNs
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fun repl e =
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let open TextIO
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@ -57,10 +55,10 @@ fun repl e =
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print("user> ");
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case inputLine(stdIn) of
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SOME(line) =>
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let val (e', s) = rep e line
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let val s = rep e line
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val _ = print(s ^ "\n")
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in
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repl e'
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repl e
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end
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| NONE => ()
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) end
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@ -2,42 +2,38 @@ fun read s =
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readStr s
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fun eval e (LIST (SYMBOL "def!"::args)) = evalDef e args
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| eval e (LIST (SYMBOL "let*"::args)) = evalLet e args
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| eval e (LIST (SYMBOL "do"::args)) = evalDo e args
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| eval e (LIST (SYMBOL "if"::args)) = evalIf e args
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| eval e (LIST (SYMBOL "let*"::args)) = (e, evalLet e args)
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| eval e (LIST (SYMBOL "fn*"::args)) = (e, evalFn e args)
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| eval e (LIST (a::args)) = evalApply e (eval' e a) args
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| eval e (SYMBOL s) = (e, evalSymbol e s)
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| eval e ast = (e, ast)
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| eval e (LIST (SYMBOL "fn*"::args)) = evalFn e args
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| eval e (LIST (a::args)) = evalApply e (eval e a) args
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| eval e (SYMBOL s) = evalSymbol e s
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| eval e ast = ast
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and eval' e ast = (#2 o eval e) ast
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and evalDef e [SYMBOL s, ast] = let val v = eval' e ast in (def s v e, v) end
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and evalDef e [SYMBOL s, ast] = let val v = eval e ast in (def s v e; v) end
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| evalDef _ _ = raise NotApplicable "def! needs a symbol and a form to evaluate"
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and evalLet e [LIST bs, ast] = eval' (bind bs e) ast
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and evalLet e [LIST bs, ast] = eval (bind bs (inside e)) ast
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| evalLet _ _ = raise NotApplicable "let* needs a list of bindings and a form to evaluate"
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and evalDo e (x::xs) = foldl (fn (x, (e,_)) => eval e x) (eval e x) xs
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and evalDo e (x::xs) = foldl (fn (x, _) => eval e x) (eval e x) xs
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| evalDo _ _ = raise NotApplicable "do needs at least one argument"
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and evalIf e [c,a,b] = eval e c |> (fn (e,c) => eval e (if truthy c then a else b))
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and evalIf e [c,a,b] = if truthy (eval e c) then eval e a else eval e b
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| evalIf e [c,a] = evalIf e [c,a,NIL]
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| evalIf _ _ = raise NotApplicable "if needs two or three arguments"
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(* TODO: Wrapping, binding, and mutating an env must be separate things *)
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and evalFn c [(LIST binds),body] = FN6 (fn (e) => fn (exprs) => eval (bind (interleave binds exprs) (wrap e c)) body)
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and evalFn c [(LIST binds),body] = CLOSURE (fn (e) => fn (exprs) => eval (bind (interleave binds exprs) (inside (wrap e c))) body)
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| evalFn _ _ = raise NotApplicable "fn* needs a list of bindings and a body"
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and evalApply e (FN4 (f)) args = (e, f e (map (eval' e) args))
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| evalApply e (FN6 (f)) args = f e (map (eval' e) args)
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| evalApply e (FN f) args = (e, f (map (eval' e) args))
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and evalApply e (CLOSURE (f)) args = f e (map (eval e) args)
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| evalApply e (FN f) args = f (map (eval e) args)
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| evalApply _ x args = raise NotApplicable (prStr x ^ " is not applicable on " ^ prStr (LIST args))
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and evalSymbol e s = valOrElse (lookup e s)
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(fn _ => raise NotDefined ("symbol '" ^ s ^ "' not found"))
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and bind (SYMBOL s::v::rest) e = def s (eval' e v) e |> bind rest
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and bind (SYMBOL s::v::rest) e = (def s (eval e v) e; bind rest e)
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| bind [] e = e
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| bind _ _ = raise NotApplicable "bindings must be a list of symbol/form pairs"
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@ -45,18 +41,13 @@ fun print f =
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prReadableStr f
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fun rep e s =
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s |> read |> eval e |> (fn (e, v) => (e, print v))
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handle Nothing => (e, "")
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| SyntaxError msg => (e, "SYNTAX ERROR: " ^ msg)
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| NotApplicable msg => (e, "CANNOT APPLY: " ^ msg)
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| NotDefined msg => (e, "NOT DEFINED: " ^ msg)
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s |> read |> eval e |> print
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handle Nothing => ""
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| SyntaxError msg => "SYNTAX ERROR: " ^ msg
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| NotApplicable msg => "CANNOT APPLY: " ^ msg
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| NotDefined msg => "NOT DEFINED: " ^ msg
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val initEnv = ENV [] |> bind coreNs
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|> bind [
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SYMBOL "eval",
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FN6 (fn (e) => fn ([x]) => eval e x
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| _ => raise NotApplicable "'eval' requires one argument")
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]
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val initEnv = ENV (NS (ref [])) |> bind coreNs
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fun repl e =
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let open TextIO
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@ -64,10 +55,10 @@ fun repl e =
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print("user> ");
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case inputLine(stdIn) of
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SOME(line) =>
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let val (e', s) = rep e line
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let val s = rep e line
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val _ = print(s ^ "\n")
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in
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repl e'
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repl e
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end
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| NONE => ()
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) end
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@ -78,4 +69,12 @@ val prelude = " \
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\ (fn* (f) \
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\ (eval (read-string (str \"(do \" (slurp f) \"\nnil)\")))))"
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fun main () = (rep initEnv prelude) |> #1 |> repl
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fun main () = (
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bind [
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SYMBOL "eval",
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FN (fn ([x]) => eval initEnv x
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| _ => raise NotApplicable "'eval' requires one argument")
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] initEnv;
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rep initEnv prelude;
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repl initEnv
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)
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@ -6,10 +6,12 @@ datatype mal_type = NIL
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| LIST of mal_type list
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| ATOM of mal_type ref
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| FN of mal_type list -> mal_type
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| FN4 of mal_env -> mal_type list -> mal_type
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| FN6 of mal_env -> mal_type list -> (mal_env * mal_type)
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| CLOSURE of mal_env -> mal_type list -> mal_type
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and mal_env = ENV of (string * mal_type) list
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and mal_ns = NS of (string * mal_type) list ref
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and mal_env = ENV of mal_ns
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| INNER of mal_ns * mal_env
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fun truthy (BOOL false) = false
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| truthy NIL = false
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