mirror of
https://github.com/kanaka/mal.git
synced 2024-09-20 10:07:45 +03:00
96 lines
4.2 KiB
OCaml
96 lines
4.2 KiB
OCaml
module T = Types.Types
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let repl_env = Env.make (Some Core.ns)
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let rec eval_ast ast env =
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match ast with
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| T.Symbol s -> Env.get env ast
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| T.List { T.value = xs; T.meta = meta }
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-> T.List { T.value = (List.map (fun x -> eval x env) xs);
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T.meta = meta }
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| T.Vector { T.value = xs; T.meta = meta }
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-> T.Vector { T.value = (List.map (fun x -> eval x env) xs);
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T.meta = meta }
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| T.Map { T.value = xs; T.meta = meta }
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-> T.Map {T.meta = meta;
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T.value = (Types.MalMap.fold
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(fun k v m
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-> Types.MalMap.add (eval k env) (eval v env) m)
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xs
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Types.MalMap.empty)}
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| _ -> ast
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and eval ast env =
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match ast with
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| T.List { T.value = [] } -> ast
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| T.List { T.value = [(T.Symbol { T.value = "def!" }); key; expr] } ->
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let value = (eval expr env) in
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Env.set env key value; value
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| T.List { T.value = [(T.Symbol { T.value = "let*" }); (T.Vector { T.value = bindings }); body] }
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| T.List { T.value = [(T.Symbol { T.value = "let*" }); (T.List { T.value = bindings }); body] } ->
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(let sub_env = Env.make (Some env) in
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let rec bind_pairs = (function
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| sym :: expr :: more ->
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Env.set sub_env sym (eval expr sub_env);
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bind_pairs more
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| _::[] -> raise (Invalid_argument "let* bindings must be an even number of forms")
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| [] -> ())
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in bind_pairs bindings;
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eval body sub_env)
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| T.List { T.value = ((T.Symbol { T.value = "do" }) :: body) } ->
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List.fold_left (fun x expr -> eval expr env) T.Nil body
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| T.List { T.value = [T.Symbol { T.value = "if" }; test; then_expr; else_expr] } ->
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if Types.to_bool (eval test env) then (eval then_expr env) else (eval else_expr env)
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| T.List { T.value = [T.Symbol { T.value = "if" }; test; then_expr] } ->
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if Types.to_bool (eval test env) then (eval then_expr env) else T.Nil
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| T.List { T.value = [T.Symbol { T.value = "fn*" }; T.Vector { T.value = arg_names }; expr] }
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| T.List { T.value = [T.Symbol { T.value = "fn*" }; T.List { T.value = arg_names }; expr] } ->
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Types.fn
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(function args ->
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let sub_env = Env.make (Some env) in
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let rec bind_args a b =
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(match a, b with
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| [T.Symbol { T.value = "&" }; name], args -> Env.set sub_env name (Types.list args);
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| (name :: names), (arg :: args) ->
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Env.set sub_env name arg;
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bind_args names args;
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| [], [] -> ()
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| _ -> raise (Invalid_argument "Bad param count in fn call"))
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in bind_args arg_names args;
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eval expr sub_env)
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| T.List _ ->
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(match eval_ast ast env with
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| T.List { T.value = ((T.Fn { T.value = f }) :: args) } -> f args
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| _ -> raise (Invalid_argument "Cannot invoke non-function"))
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| _ -> eval_ast ast env
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let read str = Reader.read_str str
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let print exp = Printer.pr_str exp true
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let rep str env = print (eval (read str) env)
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let rec main =
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try
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Core.init Core.ns;
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Env.set repl_env (Types.symbol "*ARGV*")
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(Types.list (if Array.length Sys.argv > 1
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then (List.map (fun x -> T.String x) (List.tl (List.tl (Array.to_list Sys.argv))))
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else []));
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Env.set repl_env (Types.symbol "eval")
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(Types.fn (function [ast] -> eval ast repl_env | _ -> T.Nil));
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ignore (rep "(def! load-file (fn* (f) (eval (read-string (str \"(do \" (slurp f) \")\")))))" repl_env);
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ignore (rep "(def! not (fn* (a) (if a false true)))" repl_env);
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if Array.length Sys.argv > 1 then
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ignore (rep ("(load-file \"" ^ Sys.argv.(1) ^ "\")") repl_env)
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else
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while true do
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print_string "user> ";
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let line = read_line () in
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try
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print_endline (rep line repl_env);
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with End_of_file -> ()
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| Invalid_argument x ->
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output_string stderr ("Invalid_argument exception: " ^ x ^ "\n");
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flush stderr
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done
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with End_of_file -> ()
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