-The FFI can be split up into two complementary halves; one half that
-provides Haskell constructs for importing foreign functionality into
-Haskell, the other which lets you expose Haskell functions to the
-outside world. We start with the former, how to import external
-functionality into Haskell.
+a low-level marshalling library, which is part of the
+<Emphasis>Language</Emphasis> part of the <Emphasis>Haskell Extension
+Library</Emphasis> (see <xref linkend="sec-Storable">), and a
+</Para>
+</ListItem>
+
+<ListItem>
+<Para>
+a high-level marshalling library, which is still under development.
+</Para>
+</ListItem>
+
+</OrderedList>
+Before diving into the details of the language extension coming with the FFI,
+let us briefly outline the two other components of the interface.
+</Para>
+
+<Para>
+The low-level marshalling library consists of a portion that is independent of
+the targeted foreign language and dedicated support for Haskell bindings to C
+libraries (special support for other languages may be added in the future).
+The language independent part is given by the module
+<literal>Foreign</literal> module (see <xref linkend="sec-Foreign">). It
+provides support for handling references to foreign structures, for passing
+references to Haskell structures out to foreign routines, and for storing
+primitive data types in raw memory blocks in a portable manner. The support
+for C libraries essentially provides Haskell representations for all basic
+types of C (see <xref linkend="sec-CTypes"> and <xref
+linkend="sec-CTypesISO">).
+</Para>
+
+<Para>
+The high-level library, of which the interface definition is not yet
+finalised, provides routines for marshalling complex Haskell structures as
+well as handling out and in-out parameters in a convenient, yet protable way.
+</Para>
+
+<Para>
+In the following, we will discuss the language extensions of the FFI (ie, the
+first point above). They can be split up into two complementary halves; one
+half that provides Haskell constructs for importing foreign functionality into
+Haskell, the other which lets you expose Haskell functions to the outside
+world. We start with the former, how to import external functionality into
+Haskell.