Ocaml: Added step 1, missing some optional functionality

1 files changed, 66 insertions, 0 deletions

diff --git a/ocaml/reader.ml b/ocaml/reader.ml
new file mode 100644
index 0000000..51ab522
--- /dev/null
+++ b/ocaml/reader.ml
@@ -0,0 +1,66 @@
+let find_re re str =
+  List.map (function | Str.Delim x -> x | Str.Text x -> "impossible!")
+    (List.filter (function | Str.Delim x -> true | Str.Text x -> false)
+      (Str.full_split re str)) ;;
+
+let token_re = (Str.regexp "~@\\|[][{}()'`~^@]\\|\"\\(\\\\.\\|[^\"]\\)*\"\\|;.*\\|[^][ 	\n{}('\"`,;)]*")
+
+type reader = {
+  form : Types.mal_type;
+  tokens : string list;
+}
+
+type list_reader = {
+  list_form : Types.mal_type list;
+  tokens : string list;
+}
+
+let read_atom token =
+  match token with
+    | "nil" -> Types.Nil
+    | "true" -> Types.Bool true
+    | "false" -> Types.Bool false
+    | _ ->
+    match token.[0] with
+      | '0'..'9' -> Types.Int (int_of_string token)
+      | '"' -> Types.String (Str.global_replace (Str.regexp "\\\\\\(.\\)")
+                                                "\\1"
+                                                (String.sub token 1 ((String.length token) - 2)))
+      | ':' -> Types.Keyword (Str.replace_first (Str.regexp "^:") "" token)
+      | _ -> Types.Symbol token
+
+let rec read_list list_reader =
+  match list_reader.tokens with
+    | [] -> output_string stderr "expected ')', got EOF\n";
+            flush stderr;
+            raise End_of_file;
+    | token :: tokens ->
+      if Str.string_match (Str.regexp "[])}]") token 0 then
+	{list_form = list_reader.list_form; tokens = tokens}
+      else
+	let reader = read_form list_reader.tokens in
+          read_list {list_form = list_reader.list_form @ [reader.form];
+	             tokens = reader.tokens}
+and read_quote sym tokens =
+  let reader = read_form tokens in
+    {form = Types.MalList [ Types.Symbol sym; reader.form ];
+     tokens = reader.tokens}
+and read_form all_tokens =
+  match all_tokens with
+    | [] -> raise End_of_file;
+    | token :: tokens ->
+      match token with
+        | "'" -> 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 read_str str = (read_form (List.filter ((<>) "") (find_re token_re str))).form
+