Basic functionality works.

cstring-mlton.sml

@@ -0,0 +1,84 @@
+structure Fail :> sig
+        val outOfMemory: unit -> 'a
+        val unsupportedSize: unit -> 'a
+end = struct
+        fun die message = (
+                TextIO.output (
+                        TextIO.stdErr
+                        , message ^ "\n"
+                ); OS.Process.exit OS.Process.failure
+        )
+        fun outOfMemory () = die "out of memory"
+        fun unsupportedSize () = die "unsupported type size"
+end
+
+structure Malloc :> sig
+        val f: int -> MLton.Pointer.t
+end = struct
+        val malloc32 = _import "malloc": Word32.word -> MLton.Pointer.t;
+        val malloc64 = _import "malloc": Word64.word -> MLton.Pointer.t;
+        val f = case MLton.Pointer.sizeofPointer of
+                0w4 => malloc32 o Word32.fromInt
+                | 0w8 => malloc64 o Word64.fromInt
+                | _ => Fail.unsupportedSize ()
+end
+
+structure Strlen :> sig
+        val f: MLton.Pointer.t -> int
+end = struct
+        val strlen32 = _import "strlen": MLton.Pointer.t -> Word32.word;
+        val strlen64 = _import "strlen": MLton.Pointer.t -> Word64.word;
+        val f = case MLton.Pointer.sizeofPointer of
+                0w4 => Word32.toInt o strlen32
+                | 0w8 => Word64.toInt o strlen64
+                | _ => Fail.unsupportedSize ()
+end
+
+structure CString :> sig
+    type p
+    type t
+    val app: (p -> 'a) -> t -> 'a
+    val fromString: string -> t
+    val fromPointer: p -> t
+    val toString: t -> string
+    val size: t -> int
+    val sub: t * int -> char
+end = struct
+    type p = MLton.Pointer.t
+    type t = p MLton.Finalizable.t
+    fun app f t = MLton.Finalizable.withValue (t, f)
+    fun fromPointer pointer = MLton.Finalizable.new pointer
+    local
+        val malloc = Malloc.f
+        val free = _import "free": MLton.Pointer.t -> unit;
+    in
+        fun fromString string =
+    	let val length = String.size string
+    	    val pointer = malloc (length + 1)
+    	    val () = if pointer = MLton.Pointer.null
+                         then (TextIO.output (TextIO.stdErr, "out of memory\n");
+                               OS.Process.exit OS.Process.failure)
+                         else ()
+    	    val t = MLton.Finalizable.new pointer
+    	in
+    	    MLton.Finalizable.addFinalizer (t, free);
+                app (fn pointer =>
+                        (CharVector.appi (fn (index, character) =>
+    					 MLton.Pointer.setWord8
+                                                 ( pointer
+    				             , index
+    				             , Byte.charToByte character
+    					     ))
+                                         string;
+                         MLton.Pointer.setWord8 (pointer, length, 0w0)))
+                    t;
+                t
+    	end
+    end
+    fun sub (t, index) =
+    	app (fn pointer => Byte.byteToChar (MLton.Pointer.getWord8 (pointer, index))) t
+    fun size t = app Strlen.f t
+    fun toVector t = CharVector.tabulate (size t, fn index => sub (t, index))
+    val toString = toVector
+end
+

fetchurl.mlb

@@ -0,0 +1,4 @@
+$(SML_LIB)/basis/basis.mlb
+smlcurl.mlb
+
+fetchurl.sml