From 60d744e32f64dbe8badadbd60d2b5e3d092ec8a2 Mon Sep 17 00:00:00 2001
From: "Richard W.M. Jones" <rjones@redhat.com>
Date: Sat, 29 Dec 2012 13:38:13 +0000
Subject: [PATCH] haskell: Implement 'head' and 'tail' by hiding the Prelude
 functions.

---
 generator/haskell.ml | 41 +++++++++++++++++------------------------
 src/guestfs.pod      |  6 ------
 2 files changed, 17 insertions(+), 30 deletions(-)

diff --git a/generator/haskell.ml b/generator/haskell.ml
index 21b251d1e..795f36c3d 100644
--- a/generator/haskell.ml
+++ b/generator/haskell.ml
@@ -34,27 +34,20 @@ let rec generate_haskell_hs () =
   (* See guestfs(3)/Haskell for limitations of the current Haskell
    * bindings.  Please help out! XXX
    *)
-  let can_generate name style =
-    match name with
-    (* GHC error: "Ambiguous occurrence `head'" etc. because these
-     * clash with Prelude functions with the same name.
-     *)
-    | "head" | "tail" -> false
-    | _ ->
-      match style with
-      | _, _, (_::_) -> false (* no optional args yet *)
-      | RErr, _, []
-      | RInt _, _, []
-      | RInt64 _, _, []
-      | RBool _, _, []
-      | RConstString _, _, []
-      | RString _, _, []
-      | RStringList _, _, []
-      | RHashtable _, _, [] -> true
-      | RStruct _, _, []
-      | RStructList _, _, []
-      | RBufferOut _, _, []
-      | RConstOptString _, _, [] -> false
+  let can_generate = function
+    | _, _, (_::_) -> false (* no optional args yet *)
+    | RErr, _, []
+    | RInt _, _, []
+    | RInt64 _, _, []
+    | RBool _, _, []
+    | RConstString _, _, []
+    | RString _, _, []
+    | RStringList _, _, []
+    | RHashtable _, _, [] -> true
+    | RStruct _, _, []
+    | RStructList _, _, []
+    | RBufferOut _, _, []
+    | RConstOptString _, _, [] -> false
   in
 
   pr "\
@@ -66,7 +59,7 @@ module Guestfs (
   (* List out the names of the actions we want to export. *)
   List.iter (
     fun { name = name; style = style } ->
-      if can_generate name style then pr ",\n  %s" name
+      if can_generate style then pr ",\n  %s" name
   ) all_functions;
 
   pr "
@@ -75,7 +68,7 @@ module Guestfs (
 -- Unfortunately some symbols duplicate ones already present
 -- in Prelude.  We don't know which, so we hard-code a list
 -- here.
-import Prelude hiding (truncate)
+import Prelude hiding (head, tail, truncate)
 
 import Foreign
 import Foreign.C
@@ -138,7 +131,7 @@ assocListOfHashtable (a:b:rest) = (a,b) : assocListOfHashtable rest
   List.iter (
     fun { name = name; style = (ret, args, optargs as style);
           c_function = c_function } ->
-      if can_generate name style then (
+      if can_generate style then (
         pr "foreign import ccall unsafe \"guestfs.h %s\" c_%s\n"
           c_function name;
         pr "  :: ";
diff --git a/src/guestfs.pod b/src/guestfs.pod
index 11622a278..68226c491 100644
--- a/src/guestfs.pod
+++ b/src/guestfs.pod
@@ -949,12 +949,6 @@ A tiny number of obscure functions that return constant strings
 
 =back
 
-=item *
-
-The functions L</guestfs_head> and L</guestfs_tail> are not
-bound, because these names conflict with C<Prelude.head> and
-C<Prelude.tail>.
-
 =back
 
 =item B<Java>