module T = Types.Types let repl_env = Env.make (Some Core.ns) let rec quasiquote ast = match ast with | T.List { T.value = [T.Symbol {T.value = "unquote"}; ast] } -> ast | T.Vector { T.value = [T.Symbol {T.value = "unquote"}; ast] } -> ast | T.List { T.value = T.List { T.value = [T.Symbol {T.value = "splice-unquote"}; head]} :: tail } | T.Vector { T.value = T.List { T.value = [T.Symbol {T.value = "splice-unquote"}; head]} :: tail } -> Types.list [Types.symbol "concat"; head; quasiquote (Types.list tail)] | T.List { T.value = head :: tail } | T.Vector { T.value = head :: tail } -> Types.list [Types.symbol "cons"; quasiquote head; quasiquote (Types.list tail) ] | ast -> Types.list [Types.symbol "quote"; ast] let kw_macro = T.Keyword "macro" let is_macro_call ast env = match ast with | T.List { T.value = s :: args } -> (match (try Env.get env s with _ -> T.Nil) with | T.Fn { T.meta = T.Map { T.value = meta } } -> Types.MalMap.mem kw_macro meta && Types.to_bool (Types.MalMap.find kw_macro meta) | _ -> false) | _ -> false let rec macroexpand ast env = if is_macro_call ast env then match ast with | T.List { T.value = s :: args } -> (match (try Env.get env s with _ -> T.Nil) with | T.Fn { T.value = f } -> macroexpand (f args) env | _ -> ast) | _ -> ast else ast let rec eval_ast ast env = match ast with | T.Symbol s -> Env.get env ast | T.List { T.value = xs; T.meta = meta } -> T.List { T.value = (List.map (fun x -> eval x env) xs); T.meta = meta } | T.Vector { T.value = xs; T.meta = meta } -> T.Vector { T.value = (List.map (fun x -> eval x env) xs); T.meta = meta } | T.Map { T.value = xs; T.meta = meta } -> T.Map {T.meta = meta; T.value = (Types.MalMap.fold (fun k v m -> Types.MalMap.add (eval k env) (eval v env) m) xs Types.MalMap.empty)} | _ -> ast and eval ast env = match macroexpand ast env with | T.List { T.value = [] } -> ast | T.List { T.value = [(T.Symbol { T.value = "def!" }); key; expr] } -> let value = (eval expr env) in Env.set env key value; value | T.List { T.value = [(T.Symbol { T.value = "defmacro!" }); key; expr] } -> (match (eval expr env) with | T.Fn { T.value = f; T.meta = meta } -> let fn = T.Fn { T.value = f; meta = Core.assoc [meta; kw_macro; (T.Bool true)]} in Env.set env key fn; fn | _ -> raise (Invalid_argument "defmacro! value must be a fn")) | T.List { T.value = [(T.Symbol { T.value = "let*" }); (T.Vector { T.value = bindings }); body] } | T.List { T.value = [(T.Symbol { T.value = "let*" }); (T.List { T.value = bindings }); body] } -> (let sub_env = Env.make (Some env) in let rec bind_pairs = (function | sym :: expr :: more -> Env.set sub_env sym (eval expr sub_env); bind_pairs more | _::[] -> raise (Invalid_argument "let* bindings must be an even number of forms") | [] -> ()) in bind_pairs bindings; eval body sub_env) | T.List { T.value = ((T.Symbol { T.value = "do" }) :: body) } -> List.fold_left (fun x expr -> eval expr env) T.Nil body | T.List { T.value = [T.Symbol { T.value = "if" }; test; then_expr; else_expr] } -> if Types.to_bool (eval test env) then (eval then_expr env) else (eval else_expr env) | T.List { T.value = [T.Symbol { T.value = "if" }; test; then_expr] } -> if Types.to_bool (eval test env) then (eval then_expr env) else T.Nil | T.List { T.value = [T.Symbol { T.value = "fn*" }; T.Vector { T.value = arg_names }; expr] } | T.List { T.value = [T.Symbol { T.value = "fn*" }; T.List { T.value = arg_names }; expr] } -> Types.fn (function args -> let sub_env = Env.make (Some env) in let rec bind_args a b = (match a, b with | [T.Symbol { T.value = "&" }; name], args -> Env.set sub_env name (Types.list args); | (name :: names), (arg :: args) -> Env.set sub_env name arg; bind_args names args; | [], [] -> () | _ -> raise (Invalid_argument "Bad param count in fn call")) in bind_args arg_names args; eval expr sub_env) | T.List { T.value = [T.Symbol { T.value = "quote" }; ast] } -> ast | T.List { T.value = [T.Symbol { T.value = "quasiquote" }; ast] } -> eval (quasiquote ast) env | T.List { T.value = [T.Symbol { T.value = "macroexpand" }; ast] } -> macroexpand ast env | T.List _ as ast -> (match eval_ast ast env with | T.List { T.value = ((T.Fn { T.value = f }) :: args) } -> f args | _ -> raise (Invalid_argument "Cannot invoke non-function")) | ast -> eval_ast ast env let read str = Reader.read_str str let print exp = Printer.pr_str exp true let rep str env = print (eval (read str) env) let rec main = try Core.init Core.ns; Env.set repl_env (Types.symbol "*ARGV*") (Types.list (if Array.length Sys.argv > 1 then (List.map (fun x -> T.String x) (List.tl (List.tl (Array.to_list Sys.argv)))) else [])); Env.set repl_env (Types.symbol "eval") (Types.fn (function [ast] -> eval ast repl_env | _ -> T.Nil)); ignore (rep "(def! load-file (fn* (f) (eval (read-string (str \"(do \" (slurp f) \")\")))))" repl_env); ignore (rep "(def! not (fn* (a) (if a false true)))" repl_env); ignore (rep "(defmacro! cond (fn* (& xs) (if (> (count xs) 0) (list 'if (first xs) (if (> (count xs) 1) (nth xs 1) (throw \"odd number of forms to cond\")) (cons 'cond (rest (rest xs)))))))" repl_env); ignore (rep "(defmacro! or (fn* (& xs) (if (empty? xs) nil (if (= 1 (count xs)) (first xs) `(let* (or_FIXME ~(first xs)) (if or_FIXME or_FIXME (or ~@(rest xs))))))))" repl_env); if Array.length Sys.argv > 1 then ignore (rep ("(load-file \"" ^ Sys.argv.(1) ^ "\")") repl_env) else while true do print_string "user> "; let line = read_line () in try print_endline (rep line repl_env); with End_of_file -> () | Invalid_argument x -> output_string stderr ("Invalid_argument exception: " ^ x ^ "\n"); flush stderr | _ -> output_string stderr ("Erroringness!\n"); flush stderr done with End_of_file -> ()