Ocaml: Add step 2, nothing optional

5 files changed, 69 insertions, 16 deletions

diff --git a/ocaml/Makefile b/ocaml/Makefile
index a46b82a..a526ecf 100644
--- a/ocaml/Makefile
+++ b/ocaml/Makefile
@@ -1,14 +1,17 @@
-STEPS = step0_repl.ml step1_read_print.ml
+STEPS = step0_repl.ml step1_read_print.ml step2_eval.ml
 MODULES = types.ml reader.ml printer.ml
 LIBS = str.cma 
 
 BINS = $(STEPS:%.ml=%)
 
-all: $(BINS) mal oc
+all: $(BINS) mal
 
 mal: $(word $(words $(BINS)),$(BINS))
 	cp $< $@
 
+repl: $(MODULES)
+	rlwrap ocaml $(LIBS) $(MODULES:%.ml=%.cmo)
+
 $(BINS): %: %.ml $(MODULES)
 	ocamlc $(LIBS) $(MODULES) $< -o $@
 
diff --git a/ocaml/printer.ml b/ocaml/printer.ml
index 30e4415..e87b3eb 100644
--- a/ocaml/printer.ml
+++ b/ocaml/printer.ml
@@ -13,3 +13,4 @@ let rec pr_str mal_obj =
                         ^ (Str.global_replace (Str.regexp "\"") "\\\"" s)
                         ^ "\""
     | Types.MalList xs -> "(" ^ (join " " (List.map pr_str xs)) ^ ")"
+    | Types.Fn f -> "<fn>"
diff --git a/ocaml/reader.ml b/ocaml/reader.ml
index 51ab522..c32fa91 100644
--- a/ocaml/reader.ml
+++ b/ocaml/reader.ml
@@ -3,7 +3,7 @@ let find_re re str =
     (List.filter (function | Str.Delim x -> true | Str.Text x -> false)
       (Str.full_split re str)) ;;
 
-let token_re = (Str.regexp "~@\\|[][{}()'`~^@]\\|\"\\(\\\\.\\|[^\"]\\)*\"\\|;.*\\|[^][ 	\n{}('\"`,;)]*")
+let token_re = (Str.regexp "~@\\|[][{}()'`~^@]\\|\"\\(\\\\.\\|[^\"]\\)*\"\\|;.*\\|[^][  \n{}('\"`,;)]*")
 
 type reader = {
   form : Types.mal_type;
@@ -36,11 +36,11 @@ let rec read_list list_reader =
             raise End_of_file;
     | token :: tokens ->
       if Str.string_match (Str.regexp "[])}]") token 0 then
-	{list_form = list_reader.list_form; tokens = tokens}
+        {list_form = list_reader.list_form; tokens = tokens}
       else
-	let reader = read_form list_reader.tokens in
+        let reader = read_form list_reader.tokens in
           read_list {list_form = list_reader.list_form @ [reader.form];
-	             tokens = reader.tokens}
+                     tokens = reader.tokens}
 and read_quote sym tokens =
   let reader = read_form tokens in
     {form = Types.MalList [ Types.Symbol sym; reader.form ];
@@ -50,17 +50,15 @@ and read_form all_tokens =
     | [] -> raise End_of_file;
     | token :: tokens ->
       match token with
-        | "'" -> read_quote "quote" tokens
-        | "`" -> read_quote "quasiquote" tokens
-        | "~" -> read_quote "unquote" tokens
+        | "'"  -> read_quote "quote" tokens
+        | "`"  -> read_quote "quasiquote" tokens
+        | "~"  -> read_quote "unquote" tokens
         | "~@" -> read_quote "splice-unquote" tokens
-        | _ ->
-          match token.[0] with
-           | '[' | '(' | '{' -> let list_reader =
-              read_list {list_form = []; tokens = tokens} in
-	        {form = Types.MalList list_reader.list_form;
-                 tokens = list_reader.tokens}
-           | _ -> {form = read_atom token; tokens = tokens}
+        | "[" | "(" | "{" -> let list_reader =
+           read_list {list_form = []; tokens = tokens} in
+             {form = Types.MalList list_reader.list_form;
+              tokens = list_reader.tokens}
+        | _ -> {form = read_atom token; tokens = tokens}
 
 let read_str str = (read_form (List.filter ((<>) "") (find_re token_re str))).form
 
diff --git a/ocaml/step2_eval.ml b/ocaml/step2_eval.ml
new file mode 100644
index 0000000..4337a11
--- /dev/null
+++ b/ocaml/step2_eval.ml
@@ -0,0 +1,50 @@
+module Env =
+  Map.Make (
+    String
+    (*(struct
+       type t = Types.Symbol
+       let compare (Types.Symbol a) (Types.Symbol b) = compare a b
+    end)*)
+    )
+
+let num_fun f = Types.Fn
+  (function
+    | [(Types.Int a); (Types.Int b)] -> Types.Int (f a b)
+    | _ -> raise (Invalid_argument "Numeric args required for this Mal builtin"))
+
+let env = ref (List.fold_left (fun a b -> b a) Env.empty
+  [ Env.add "+" (num_fun ( + ));
+    Env.add "-" (num_fun ( - ));
+    Env.add "*" (num_fun ( * ));
+    Env.add "/" (num_fun ( / )) ])
+
+let rec eval_ast ast env =
+  match ast with
+    | Types.Symbol s ->
+        (try Env.find s !env
+         with Not_found -> raise (Invalid_argument ("Symbol '" ^ s ^ "' not found")))
+    | Types.MalList xs -> Types.MalList (List.map (fun x -> eval x env) xs)
+    | _ -> ast
+and eval ast env =
+  let result = eval_ast ast env in
+    match result with
+      | Types.MalList ((Types.Fn f) :: args) -> (f args)
+      | _ -> result
+
+let read str = Reader.read_str str
+let print exp = Printer.pr_str exp
+let rep str env = print (eval (read str) env)
+
+let rec main =
+  try
+    while true do
+      print_string "user> ";
+      let line = read_line () in
+        try
+          print_endline (rep line env);
+        with End_of_file -> ()
+         | Invalid_argument x ->
+             output_string stderr ("Invalid_argument exception: " ^ x ^ "\n");
+             flush stderr
+    done
+  with End_of_file -> ()
diff --git a/ocaml/types.ml b/ocaml/types.ml
index 92f3030..60d3725 100644
--- a/ocaml/types.ml
+++ b/ocaml/types.ml
@@ -6,3 +6,4 @@ type mal_type =
   | Nil
   | Bool of bool
   | String of string
+  | Fn of (mal_type list -> mal_type)