src/Tools/WWW_Find/mime.ML

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/Tools/WWW_Find/mime.ML	Fri Nov 20 18:36:44 2009 +1100
@@ -0,0 +1,56 @@
+(*  Title:      mime_types.ML
+    Author:     Timothy Bourke, NICTA
+
+Rudimentary support for mime_types.
+*)
+
+signature MIME =
+sig
+  datatype t = Type of {
+      main : string,
+      sub : string, 
+      params : (string * string) list
+    }
+
+  val plain : t
+  val html : t
+  
+  val parse_type : string -> t option
+  val show_type : t -> string
+end;
+
+structure Mime: MIME =
+struct
+
+datatype t = Type of {
+    main : string,
+    sub : string, 
+    params : (string * string) list
+  };
+
+val strip =
+  Substring.dropl Char.isSpace
+  #> Substring.dropr Char.isSpace;
+
+val split_fields =
+  Substring.splitl (fn c => c <> #"=")
+  #> apsnd (Substring.triml 1)
+  #> pairself (Substring.string o strip);
+
+fun show_param (n, v) = concat ["; ", n, "=", v];
+
+fun show_type (Type {main, sub, params}) =
+      concat ([main, "/", sub] @ map show_param params);
+
+fun parse_type s =
+  (case Substring.fields (Char.contains "/;") (Substring.full s) of
+     t::s::ps => SOME (Type { main = (Substring.string o strip) t,
+                              sub = (Substring.string o strip) s,
+                              params = map split_fields ps })
+   | _ => NONE);
+
+val plain = the (parse_type "text/plain; charset=utf-8");
+val html = the (parse_type "text/html; charset=utf-8");
+
+end;
+