Add sample Ur/Web files

Taken from tokenrove/parsur so I don't have to worry about license
hassles.  (You may relicense these samples as necessary.)

It would be nice to have an example of the embedded SQL syntax in a
sample.

samples/UrWeb/parse.urs

@@ -0,0 +1,85 @@
+functor Make(Stream : sig type t end) : sig
+    con t :: Type -> Type
+
+    val mreturn : a ::: Type -> a -> t a
+    val mbind : a ::: Type -> b ::: Type ->
+                (t a) -> (a -> t b) -> (t b)
+    val monad_parse : monad t
+
+    val parse : a ::: Type -> t a -> Stream.t -> option a
+
+    (** Combinators *)
+    val fail : a ::: Type -> t a
+    val or : a ::: Type -> t a -> t a -> t a
+    val maybe : a ::: Type -> t a -> t (option a)
+    val maybe' : a ::: Type -> t a -> t unit
+    val many : a ::: Type -> t a -> t (list a)
+    val count : a ::: Type -> int -> t a -> t (list a)
+    val skipMany : a ::: Type -> t a -> t unit
+    val sepBy : a ::: Type -> s ::: Type -> t a -> t s -> t (list a)
+end
+
+structure String : sig
+    con t :: Type -> Type
+    val monad_parse : monad t
+
+    val parse : a ::: Type -> t a -> string -> option a
+
+    (** Combinators *)
+    val fail : a ::: Type -> t a
+    val or : a ::: Type -> t a -> t a -> t a
+    val maybe : a ::: Type -> t a -> t (option a)
+    val maybe' : a ::: Type -> t a -> t unit
+    val many : a ::: Type -> t a -> t (list a)
+    val count : a ::: Type -> int -> t a -> t (list a)
+    val skipMany : a ::: Type -> t a -> t unit
+    val sepBy : a ::: Type -> s ::: Type -> t a -> t s -> t (list a)
+
+    val eof : t unit
+    (* We provide alternative versions of some of these predicates
+     * that return t unit as a monadic syntactical convenience. *)
+    val string : string -> t string
+    val string' : string -> t unit
+    val stringCI : string -> t string
+    val stringCI' : string -> t unit
+    val char : char -> t char
+    val char' : char -> t unit
+    val take : int -> t (string*int)
+    val drop : int -> t unit
+    val satisfy : (char -> bool) -> t char
+    val skip : (char -> bool) -> t unit
+    val skipWhile : (char -> bool) -> t unit
+    val takeWhile : (char -> bool) -> t (string*int)
+    val takeWhile' : (char -> bool) -> t string (* conses *)
+    (* Well, "till" is the correct form; but "til" is in common enough
+     * usage that I'll prefer it for terseness. *)
+    val takeTil : (char -> bool) -> t (string*int)
+    val takeTil' : (char -> bool) -> t string (* conses *)
+    val takeRest : t string
+
+    (** Convenience functions *)
+    val skipSpace : t unit
+    val endOfLine : t unit
+    val unsigned_int_of_radix : int -> t int
+    (*
+     * val signed_int_of_radix : int -> t int
+     * val double : t float
+     *)
+end
+
+structure Blob : sig
+    con t :: Type -> Type
+    val monad_parse : monad t
+
+    val parse : a ::: Type -> t a -> blob -> option a
+
+    (** Combinators *)
+    val fail : a ::: Type -> t a
+    val or : a ::: Type -> t a -> t a -> t a
+    val maybe : a ::: Type -> t a -> t (option a)
+    val maybe' : a ::: Type -> t a -> t unit
+    val many : a ::: Type -> t a -> t (list a)
+    val count : a ::: Type -> int -> t a -> t (list a)
+    val skipMany : a ::: Type -> t a -> t unit
+    val sepBy : a ::: Type -> s ::: Type -> t a -> t s -> t (list a)
+end