diff --git a/samples/ATS/basis_ssntype.sats b/samples/ATS/basis_ssntype.sats
new file mode 100644
index 00000000..6da538d3
--- /dev/null
+++ b/samples/ATS/basis_ssntype.sats
@@ -0,0 +1,294 @@
+// Source: https://github.com/githwxi/ATS-Postiats-contrib/blob/201d635062d0ea64ff5ba5457a4ea0bb4d5ae202/contrib/libats-/hwxi/teaching/mysession-g/SATS/basis_ssntype.sats
+
+(*
+** Basis for g-session types
+*)
+
+(* ****** ****** *)
+//
+staload
+"./basis_intset.sats"
+//
+(* ****** ****** *)
+//
+fun{}
+channel_cap(): intGte(1)  
+//
+(* ****** ****** *)
+//
+abstype
+session_msg
+  (i:int, j:int, a:vt@ype)
+//
+(* ****** ****** *)
+
+abstype ssession_nil
+abstype ssession_cons(a:type, ssn:type)
+
+(* ****** ****** *)
+//
+stadef msg = session_msg
+//
+stadef nil = ssession_nil
+//
+stadef :: = ssession_cons
+stadef cons = ssession_cons
+//
+(* ****** ****** *)
+//
+abstype
+session_append
+  (ssn1: type, ssn2: type)
+//
+stadef append = session_append
+//
+(* ****** ****** *)
+//
+abstype
+session_choose
+(
+  i:int, ssn1:type, ssn2:type
+) (* session_choose *)
+//
+stadef choose = session_choose
+//
+(* ****** ****** *)
+//
+abstype
+session_repeat
+(
+  i:int, ssn:type(*body*)
+) (* session_repeat *)
+//
+stadef repeat = session_repeat
+//
+(* ****** ****** *)
+//
+typedef
+session_sing
+(
+  i: int
+, j: int
+, a:vt@ype
+) = cons(msg(i, j, a), nil)
+//
+(* ****** ****** *)
+//
+absvtype
+channel1_vtype
+  (G:iset, n:int, ssn:type) = ptr
+//
+vtypedef
+channel1
+  (G:iset, n:int, ssn:type) = channel1_vtype(G, n, ssn)
+//
+vtypedef
+cchannel1
+  (G:iset, n:int, ssn:type) = channel1_vtype(ncomp(n, G), n, ssn)
+//
+(* ****** ****** *)
+//
+fun{}
+channel1_get_nrole
+  {n:int}{ssn:type}{G:iset}
+  (chan: !channel1(G, n, ssn)): int(n)
+//
+fun{}
+channel1_get_group
+  {n:int}{ssn:type}{G:iset}
+  (chan: !channel1(G, n, ssn)): intset(n,G)
+//
+(* ****** ****** *)
+//
+fun
+{a:vt0p}
+channel1_close
+  {n:int}{ssn:type}{G:iset}(chan: channel1(G, n, nil)): void
+//
+(* ****** ****** *)
+//
+fun{}
+channel1_skipin
+  {a:vt0p}
+  {n:int}{ssn:type}{G:iset}
+  {i,j:nat | ismbr(G, i); ismbr(G, j)}
+(
+  !channel1(G, n, msg(i, j, a)::ssn) >> channel1(G, n, ssn)
+) : void // end-of-function
+praxi
+lemma_channel1_skipin
+  {a:vt0p}
+  {n:int}{ssn:type}{G:iset}
+  {i,j:nat | ismbr(G, i); ismbr(G, j)}
+(
+  !channel1(G, n, msg(i, j, a)::ssn) >> channel1(G, n, ssn)
+) : void // lemma_channel1_skipin
+//
+fun{}
+channel1_skipex
+  {a:vt0p}
+  {n:int}{ssn:type}{G:iset}
+  {i,j:nat | ~ismbr(G, i); ~ismbr(G, j)}
+(
+  !channel1(G, n, msg(i, j, a)::ssn) >> channel1(G, n, ssn)
+) : void // end-of-function
+praxi
+lemma_channel1_skipex
+  {a:vt0p}
+  {n:int}{ssn:type}{G:iset}
+  {i,j:nat | ~ismbr(G, i); ~ismbr(G, j)}
+(
+  !channel1(G, n, msg(i, j, a)::ssn) >> channel1(G, n, ssn)
+) : void // lemma_channel1_skipex
+//
+(* ****** ****** *)
+//
+fun
+{a:vt0p}
+channel1_send
+  {n:int}{ssn:type}{G:iset}
+  {i,j:nat | i < n; j < n; ismbr(G, i); ~ismbr(G, j)}
+(
+  !channel1(G, n, msg(i, j, a)::ssn) >> channel1(G, n, ssn), int(i), int(j), a
+) : void // end of [channel1_send]
+//
+fun
+{a:vt0p}
+channel1_recv
+  {n:int}{ssn:type}{G:iset}
+  {i,j:nat | i < n; j < n; ~ismbr(G, i); ismbr(G, j)}
+(
+  !channel1(G, n, msg(i, j, a)::ssn) >> channel1(G, n, ssn), int(i), int(j), &a? >> a
+) : void // end of [channel1_recv]
+//
+fun
+{a:vt0p}
+channel1_recv_val
+  {n:int}{ssn:type}{G:iset}
+  {i,j:nat | i < n; j < n; ~ismbr(G, i); ismbr(G, j)}
+  (!channel1(G, n, msg(i, j, a)::ssn) >> channel1(G, n, ssn), int(i), int(j)): (a)
+//
+(* ****** ****** *)
+
+fun{}
+channel1_append
+  {n:int}
+  {ssn1,ssn2:type}
+  {G:iset}
+(
+  chan: !channel1(G, n, append(ssn1, ssn2)) >> channel1(G, n, ssn2)
+, fserv: (!channel1(G, n, ssn1) >> channel1(G, n, nil)) -<lincloptr1> void
+) : void // end of [channel1_append]
+
+(* ****** ****** *)
+//
+datatype
+choosetag
+(
+  a:type, b:type, c:type
+) =
+  | choosetag_l(a, b, a) of ()
+  | choosetag_r(a, b, b) of ()
+//
+(* ****** ****** *)
+//
+fun{}
+channel1_choose_l
+  {n:int}
+  {ssn1,ssn2:type}
+  {G:iset}
+  {i:nat | i < n; ismbr(G, i)}
+(
+  !channel1(G, n, choose(i,ssn1,ssn2)) >> channel1(G, n, ssn1), i: int(i)
+) : void // end of [channel1_choose_l]
+//
+fun{}
+channel1_choose_r
+  {n:int}
+  {ssn1,ssn2:type}
+  {G:iset}
+  {i:nat | i < n; ismbr(G, i)}
+(
+  !channel1(G, n, choose(i,ssn1,ssn2)) >> channel1(G, n, ssn2), i: int(i)
+) : void // end of [channel1_choose_r]
+//
+fun{}
+channel1_choose_tag
+  {n:int}
+  {ssn1,ssn2:type}
+  {G:iset}
+  {i:nat | i < n; ~isnil(G); ~ismbr(G, i)}
+(
+  !channel1(G, n, choose(i,ssn1,ssn2)) >> channel1(G, n, ssn_chosen), i: int(i)
+) : #[ssn_chosen:type] choosetag(ssn1, ssn2, ssn_chosen)
+//
+(* ****** ****** *)
+//
+fun{}
+channel1_repeat_0
+  {n:int}
+  {ssn:type}
+  {G:iset}
+  {i:nat | i < n; ismbr(G, i)}
+(
+  !channel1(G, n, repeat(i,ssn)) >> channel1(G, n, nil), i: int(i)
+) : void // end of [channel1_repeat_nil]
+//
+fun{}
+channel1_repeat_1
+  {n:int}
+  {ssn:type}
+  {G:iset}
+  {i:nat | i < n; ismbr(G, i)}
+(
+  !channel1(G, n, repeat(i,ssn)) >> channel1(G, n, append(ssn,repeat(i,ssn))), i: int(i)
+) : void // end of [channel1_repeat_more]
+//
+fun{}
+channel1_repeat_tag
+  {n:int}
+  {ssn:type}
+  {G:iset}
+  {i:nat | i < n; ~isnil(G); ~ismbr(G, i)}
+(
+  !channel1(G, n, repeat(i,ssn)) >> channel1(G, n, ssn_chosen), i: int(i)
+) : #[ssn_chosen:type] choosetag(nil, append(ssn,repeat(i,ssn)), ssn_chosen)
+//
+(* ****** ****** *)
+//
+(*
+//
+// HX-2015-03-06:
+// This one does not work with sschoose!!!
+//
+fun{}
+channel1_link
+  {n:int}{ssn:type}
+  {G1,G2:iset | isnil(G1*G2)}
+  (channel1(G1, n, ssn), channel1(G2, n, ssn)): channel1(G1+G2, n, ssn)
+*)
+//
+fun{}
+channel1_link
+  {n:int}{ssn:type}
+  {G1,G2:iset | isful(G1+G2,n)}
+  (channel1(G1, n, ssn), channel1(G2, n, ssn)): channel1(G1*G2, n, ssn)
+//
+(* ****** ****** *)
+//
+fun{}
+channel1_link_elim
+  {n:int}{ssn:type}{G:iset}(channel1(G, n, ssn), cchannel1(G, n, ssn)): void
+//
+(* ****** ****** *)
+//
+fun{}
+cchannel1_create_exn
+  {n:nat}{ssn:type}{G:iset}
+(
+  nrole: int(n), G: intset(n), fserv: channel1(G, n, ssn) -<lincloptr1> void
+) : cchannel1(G, n, ssn) // end of [cchannel1_create_exn]
+//
+(* ****** ****** *)
+
+(* end of [basis_ssntype.sats] *)
diff --git a/samples/ATS/intinf_vt.dats b/samples/ATS/intinf_vt.dats
new file mode 100644
index 00000000..51d3af5e
--- /dev/null
+++ b/samples/ATS/intinf_vt.dats
@@ -0,0 +1,694 @@
+// Source: https://github.com/githwxi/ATS-Postiats-contrib/blob/04a984d9c08c1831f7dda8a05ce356db01f81850/contrib/libats-/hwxi/intinf/DATS/intinf_vt.dats
+
+(***********************************************************************)
+(*                                                                     *)
+(*                         ATS/contrib/atshwxi                         *)
+(*                                                                     *)
+(***********************************************************************)
+
+(*
+** Copyright (C) 2013 Hongwei Xi, ATS Trustful Software, Inc.
+**
+** Permission is hereby granted, free of charge, to any person obtaining a
+** copy of this software and associated documentation files (the "Software"),
+** to deal in the Software without restriction, including without limitation
+** the rights to use, copy, modify, merge, publish, distribute, sublicense,
+** and/or sell copies of the Software, and to permit persons to whom the
+** Software is furnished to do so, subject to the following stated conditions:
+** 
+** The above copyright notice and this permission notice shall be included in
+** all copies or substantial portions of the Software.
+** 
+** THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+** OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+** FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+** THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+** LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+** FROM OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+** IN THE SOFTWARE.
+*)
+
+(* ****** ****** *)
+//
+// Author: Hongwei Xi
+// Authoremail: hwxi AT gmail DOT com
+// Start Time: April, 2013
+//
+(* ****** ****** *)
+
+#include
+"share/atspre_define.hats"
+
+(* ****** ****** *)
+
+staload
+UN = "prelude/SATS/unsafe.sats"
+
+(* ****** ****** *)
+
+staload
+GMP = "{$LIBGMP}/SATS/gmp.sats"
+
+(* ****** ****** *)
+
+vtypedef mpz = $GMP.mpz_vt0ype
+
+(* ****** ****** *)
+//
+staload "./../SATS/intinf.sats"
+staload "./../SATS/intinf_vt.sats"
+//
+(* ****** ****** *)
+
+macdef i2u (x) = g1int2uint_int_uint (,(x))
+
+(* ****** ****** *)
+
+local
+
+assume
+intinf_vtype
+  (i: int) = // HX: [i] is a fake
+  [l:addr] (mpz @ l, mfree_gc_v (l) | ptr l)
+// end of [intinf_vtype]
+
+in (* in of [local] *)
+
+implement{}
+intinf_make_int
+  (i) = (x) where
+{
+//
+val x = ptr_alloc<mpz> ()
+val () = $GMP.mpz_init_set_int (!(x.2), i)
+//
+} (* end of [intinf_make_int] *)
+
+implement{}
+intinf_make_uint
+  (i) = (x) where
+{
+//
+val x = ptr_alloc<mpz> ()
+val () = $GMP.mpz_init_set_uint (!(x.2), i)
+//
+} (* end of [intinf_make_uint] *)
+
+implement{}
+intinf_make_lint
+  (i) = (x) where
+{
+//
+val x = ptr_alloc<mpz> ()
+val () = $GMP.mpz_init_set_lint (!(x.2), i)
+//
+} (* end of [intinf_make_lint] *)
+
+implement{}
+intinf_make_ulint
+  (i) = (x) where
+{
+//
+val x = ptr_alloc<mpz> ()
+val () = $GMP.mpz_init_set_ulint (!(x.2), i)
+//
+} (* end of [intinf_make_ulint] *)
+
+(* ****** ****** *)
+
+implement{}
+intinf_free (x) = let
+  val (pfat, pfgc | p) = x
+  val () = $GMP.mpz_clear (!p) in ptr_free (pfgc, pfat | p)
+end (* end of [intinf_free] *)
+
+(* ****** ****** *)
+
+implement{}
+intinf_get_int (x) = $GMP.mpz_get_int (!(x.2))
+implement{}
+intinf_get_lint (x) = $GMP.mpz_get_lint (!(x.2))
+
+(* ****** ****** *)
+
+implement{}
+intinf_get_strptr
+  (x, base) = $GMP.mpz_get_str_null (base, !(x.2))
+// end of [intinf_get_strptr]
+
+(* ****** ****** *)
+
+implement{}
+fprint_intinf_base
+  (out, x, base) = let
+  val nsz = $GMP.mpz_out_str (out, base, !(x.2))
+in
+//
+if (nsz = 0) then
+  exit_errmsg (1, "libgmp/gmp: fprint_intinf_base")
+// end of [if]
+//
+end (* fprint_intinf_base *)
+
+(* ****** ****** *)
+
+implement{
+} neg_intinf0
+  (x) = (x) where
+{
+//
+val () = $GMP.mpz_neg (!(x.2))
+//
+} (* end of [neg_intinf0] *)
+
+implement{
+} neg_intinf1
+  (x) = (y) where
+{
+//
+val y = ptr_alloc<mpz> ()
+val () = $GMP.mpz_init (!(y.2))
+val () = $GMP.mpz_neg (!(y.2), !(x.2))
+//
+} (* end of [neg_intinf1] *)
+
+(* ****** ****** *)
+
+implement{
+} abs_intinf0
+  (x) = (x) where
+{
+//
+val () = $GMP.mpz_abs (!(x.2))
+//
+} (* end of [abs_intinf0] *)
+
+implement{
+} abs_intinf1
+  (x) = (y) where
+{
+//
+val y = ptr_alloc<mpz> ()
+val () = $GMP.mpz_init (!(y.2))
+val () = $GMP.mpz_abs (!(y.2), !(x.2))
+//
+} (* end of [abs_intinf1] *)
+
+(* ****** ****** *)
+
+implement{}
+succ_intinf0 (x) = add_intinf0_int (x, 1)
+implement{}
+succ_intinf1 (x) = add_intinf1_int (x, 1)
+
+(* ****** ****** *)
+
+implement{}
+pred_intinf0 (x) = sub_intinf0_int (x, 1)
+implement{}
+pred_intinf1 (x) = sub_intinf1_int (x, 1)
+
+(* ****** ****** *)
+
+implement{}
+add_intinf0_int
+  (x, y) = (x) where
+{
+//
+val () = $GMP.mpz_add2_int (!(x.2), y)
+//
+} (* end of [add_intinf0_int] *)
+
+implement{}
+add_intinf1_int
+  (x, y) = (z) where
+{
+//
+val z = ptr_alloc<mpz> ()
+val () = $GMP.mpz_init (!(z.2))
+val () = $GMP.mpz_add3_int (!(z.2), !(x.2), y)
+//
+} (* end of [add_intinf1_int] *)
+
+(* ****** ****** *)
+
+implement{}
+add_int_intinf0 (x, y) = add_intinf0_int (y, x)
+implement{}
+add_int_intinf1 (x, y) = add_intinf1_int (y, x)
+
+(* ****** ****** *)
+
+implement{}
+add_intinf0_intinf1
+  (x, y) = (x) where
+{
+//
+val () = $GMP.mpz_add2_mpz (!(x.2), !(y.2))
+//
+} (* end of [add_intinf0_intinf1] *)
+
+implement{}
+add_intinf1_intinf0
+  (x, y) = (y) where
+{
+//
+val () = $GMP.mpz_add2_mpz (!(y.2), !(x.2))
+//
+} (* end of [add_intinf1_intinf0] *)
+
+(* ****** ****** *)
+
+implement{}
+add_intinf1_intinf1
+  (x, y) = (z) where
+{
+//
+val z = ptr_alloc<mpz> ()
+val () = $GMP.mpz_init (!(z.2))
+val () = $GMP.mpz_add3_mpz (!(z.2), !(x.2), !(y.2))
+//
+} (* end of [add_intinf1_intinf1] *)
+
+(* ****** ****** *)
+
+implement{}
+sub_intinf0_int
+  (x, y) = (x) where
+{
+//
+val () = $GMP.mpz_sub2_int (!(x.2), y)
+//
+} (* end of [sub_intinf0_int] *)
+
+implement{}
+sub_intinf1_int
+  (x, y) = (z) where
+{
+//
+val z = ptr_alloc<mpz> ()
+val () = $GMP.mpz_init (!(z.2))
+val () = $GMP.mpz_sub3_int (!(z.2), !(x.2), y)
+//
+} (* end of [sub_intinf1_int] *)
+
+(* ****** ****** *)
+
+implement{}
+sub_int_intinf0 (x, y) = let
+  val z = sub_intinf0_int (y, x) in neg_intinf0 (z)
+end (* end of [sub_int_intinf0] *)
+
+implement{}
+sub_int_intinf1 (x, y) = let
+  val z = sub_intinf1_int (y, x) in neg_intinf0 (z)
+end (* end of [sub_int_intinf1] *)
+
+(* ****** ****** *)
+
+implement{}
+sub_intinf0_intinf1
+  (x, y) = (x) where
+{
+//
+val () = $GMP.mpz_sub2_mpz (!(x.2), !(y.2))
+//
+} (* end of [sub_intinf0_intinf1] *)
+
+implement{}
+sub_intinf1_intinf0
+  (x, y) = neg_intinf0 (sub_intinf0_intinf1 (y, x))
+// end of [sub_intinf1_intinf0]
+
+implement{}
+sub_intinf1_intinf1
+  (x, y) = (z) where
+{
+//
+val z = ptr_alloc<mpz> ()
+val () = $GMP.mpz_init (!(z.2))
+val () = $GMP.mpz_sub3_mpz (!(z.2), !(x.2), !(y.2))
+//
+} (* end of [sub_intinf1_intinf1] *)
+
+(* ****** ****** *)
+
+implement{}
+mul_intinf0_int
+  (x, y) = (x) where
+{
+//
+val () = $GMP.mpz_mul2_int (!(x.2), y)
+//
+} (* end of [mul_intinf0_int] *)
+
+implement{}
+mul_intinf1_int
+  (x, y) = (z) where
+{
+//
+val z = ptr_alloc<mpz> ()
+val () = $GMP.mpz_init (!(z.2))
+val () = $GMP.mpz_mul3_int (!(z.2), !(x.2), y)
+//
+} (* end of [mul_intinf1_int] *)
+
+(* ****** ****** *)
+
+implement{}
+mul_int_intinf0 (x, y) = mul_intinf0_int (y, x)
+implement{}
+mul_int_intinf1 (x, y) = mul_intinf1_int (y, x)
+
+(* ****** ****** *)
+
+implement{}
+mul_intinf0_intinf1
+  (x, y) = (x) where
+{
+//
+val () = $GMP.mpz_mul2_mpz (!(x.2), !(y.2))
+//
+} (* end of [mul_intinf0_intinf1] *)
+
+implement{}
+mul_intinf1_intinf0
+  (x, y) = (y) where
+{
+//
+val () = $GMP.mpz_mul2_mpz (!(y.2), !(x.2))
+//
+} (* end of [mul_intinf0_intinf1] *)
+
+(* ****** ****** *)
+
+implement{}
+mul_intinf1_intinf1
+  (x, y) = (z) where
+{
+//
+val z = ptr_alloc<mpz> ()
+val () = $GMP.mpz_init (!(z.2))
+val () = $GMP.mpz_mul3_mpz (!(z.2), !(x.2), !(y.2))
+//
+} (* end of [mul_intinf1_intinf1] *)
+
+(* ****** ****** *)
+
+implement{}
+div_intinf0_int
+  {i,j} (x, y) = let
+in
+//
+if y >= 0 then let
+  val () = $GMP.mpz_tdiv2_q_uint (!(x.2), i2u(y)) in x
+end else let
+  val () = $GMP.mpz_tdiv2_q_uint (!(x.2), i2u(~y)) in neg_intinf0 (x)
+end // end of [if]
+//
+end (* end of [div_intinf0_int] *)
+
+implement{}
+div_intinf1_int
+  {i,j} (x, y) = let
+//
+val z = ptr_alloc<mpz> ()
+val () = $GMP.mpz_init (!(z.2))
+//
+in
+//
+if y >= 0 then let
+  val () = $GMP.mpz_tdiv3_q_uint (!(z.2), !(x.2), i2u(y)) in z
+end else let
+  val () = $GMP.mpz_tdiv3_q_uint (!(z.2), !(x.2), i2u(~y)) in neg_intinf0 (z)
+end // end of [if]
+//
+end (* end of [div_intinf1_int] *)
+
+(* ****** ****** *)
+
+implement{}
+div_intinf0_intinf1
+  (x, y) = (x) where
+{
+//
+val () = $GMP.mpz_tdiv2_q_mpz (!(x.2), !(y.2))
+//
+} (* end of [div_intinf0_intinf1] *)
+
+(* ****** ****** *)
+
+implement{}
+div_intinf1_intinf1
+  (x, y) = (z) where
+{
+//
+val z = ptr_alloc<mpz> ()
+val () = $GMP.mpz_init (!(z.2))
+val () = $GMP.mpz_tdiv3_q_mpz (!(z.2), !(x.2), !(y.2))
+//
+} (* end of [div_intinf1_intinf1] *)
+
+(* ****** ****** *)
+
+implement{}
+ndiv_intinf0_int (x, y) = div_intinf0_int (x, y)
+implement{}
+ndiv_intinf1_int (x, y) = div_intinf1_int (x, y)
+
+(* ****** ****** *)
+
+implement{}
+nmod_intinf0_int
+  {i,j} (x, y) = let
+//
+val r =
+  $GMP.mpz_fdiv_uint (!(x.2), i2u(y))
+val () = intinf_free (x)
+//
+in
+  $UN.cast{intBtw(0,j)}(r)
+end (* end of [nmod_intinf0_int] *)
+
+implement{}
+nmod_intinf1_int
+  {i,j} (x, y) = let
+//
+val r = $GMP.mpz_fdiv_uint (!(x.2), i2u(y))
+//
+in
+  $UN.cast{intBtw(0,j)}(r)
+end (* end of [nmod_intinf1_int] *)
+
+(* ****** ****** *)
+//
+// comparison-functions
+//
+(* ****** ****** *)
+
+implement{}
+lt_intinf_int
+  {i,j} (x, y) = let
+//
+val sgn = $GMP.mpz_cmp_int (!(x.2), y)
+val ans = (if sgn < 0 then true else false): bool
+//
+in
+  $UN.cast{bool(i < j)}(sgn)
+end // end of [lt_intinf_int]
+
+implement{}
+lt_intinf_intinf
+  {i,j} (x, y) = let
+//
+val sgn = $GMP.mpz_cmp_mpz (!(x.2), !(y.2))
+val ans = (if sgn < 0 then true else false): bool
+//
+in
+  $UN.cast{bool(i < j)}(sgn)
+end // end of [lt_intinf_intinf]
+
+(* ****** ****** *)
+
+implement{}
+lte_intinf_int
+  {i,j} (x, y) = let
+//
+val sgn = $GMP.mpz_cmp_int (!(x.2), y)
+val ans = (if sgn <= 0 then true else false): bool
+//
+in
+  $UN.cast{bool(i <= j)}(sgn)
+end // end of [lte_intinf_int]
+
+implement{}
+lte_intinf_intinf
+  {i,j} (x, y) = let
+//
+val sgn = $GMP.mpz_cmp_mpz (!(x.2), !(y.2))
+val ans = (if sgn <= 0 then true else false): bool
+//
+in
+  $UN.cast{bool(i <= j)}(sgn)
+end // end of [lte_intinf_intinf]
+
+(* ****** ****** *)
+
+implement{}
+gt_intinf_int
+  {i,j} (x, y) = let
+//
+val sgn = $GMP.mpz_cmp_int (!(x.2), y)
+val ans = (if sgn > 0 then true else false): bool
+//
+in
+  $UN.cast{bool(i > j)}(sgn)
+end // end of [gt_intinf_int]
+
+implement{}
+gt_intinf_intinf
+  {i,j} (x, y) = let
+//
+val sgn = $GMP.mpz_cmp_mpz (!(x.2), !(y.2))
+val ans = (if sgn > 0 then true else false): bool
+//
+in
+  $UN.cast{bool(i > j)}(sgn)
+end // end of [gt_intinf_intinf]
+
+(* ****** ****** *)
+
+implement{}
+gte_intinf_int
+  {i,j} (x, y) = let
+//
+val sgn = $GMP.mpz_cmp_int (!(x.2), y)
+val ans = (if sgn >= 0 then true else false): bool
+//
+in
+  $UN.cast{bool(i >= j)}(sgn)
+end // end of [gte_intinf_int]
+
+implement{}
+gte_intinf_intinf
+  {i,j} (x, y) = let
+//
+val sgn = $GMP.mpz_cmp_mpz (!(x.2), !(y.2))
+val ans = (if sgn >= 0 then true else false): bool
+//
+in
+  $UN.cast{bool(i >= j)}(sgn)
+end // end of [gte_intinf_intinf]
+
+(* ****** ****** *)
+
+implement{}
+eq_intinf_int
+  {i,j} (x, y) = let
+//
+val sgn = $GMP.mpz_cmp_int (!(x.2), y)
+val ans = (if sgn = 0 then true else false): bool
+//
+in
+  $UN.cast{bool(i == j)}(sgn)
+end // end of [eq_intinf_int]
+
+implement{}
+eq_intinf_intinf
+  {i,j} (x, y) = let
+//
+val sgn = $GMP.mpz_cmp_mpz (!(x.2), !(y.2))
+val ans = (if sgn = 0 then true else false): bool
+//
+in
+  $UN.cast{bool(i == j)}(sgn)
+end // end of [eq_intinf_intinf]
+
+(* ****** ****** *)
+
+implement{}
+neq_intinf_int
+  {i,j} (x, y) = let
+//
+val sgn = $GMP.mpz_cmp_int (!(x.2), y)
+val ans = (if sgn != 0 then true else false): bool
+//
+in
+  $UN.cast{bool(i != j)}(sgn)
+end // end of [neq_intinf_int]
+
+implement{}
+neq_intinf_intinf
+  {i,j} (x, y) = let
+//
+val sgn = $GMP.mpz_cmp_mpz (!(x.2), !(y.2))
+val ans = (if sgn != 0 then true else false): bool
+//
+in
+  $UN.cast{bool(i != j)}(sgn)
+end // end of [neq_intinf_intinf]
+
+(* ****** ****** *)
+
+implement{}
+compare_intinf_int
+  {i,j} (x, y) = let
+//
+val sgn = $GMP.mpz_cmp_int (!(x.2), y)
+val sgn = (if sgn < 0 then ~1 else (if sgn > 0 then 1 else 0)): int
+//
+in
+  $UN.cast{int(sgn(i-j))}(sgn)
+end // end of [compare_intinf_int]
+
+implement{}
+compare_int_intinf
+  {i,j} (x, y) = let
+//
+val sgn = $GMP.mpz_cmp_int (!(y.2), x)
+val sgn = (if sgn > 0 then ~1 else (if sgn < 0 then 1 else 0)): int
+//
+in
+  $UN.cast{int(sgn(i-j))}(sgn)
+end // end of [compare_int_intinf]
+
+implement{}
+compare_intinf_intinf
+  {i,j} (x, y) = let
+//
+val sgn = $GMP.mpz_cmp_mpz (!(x.2), !(y.2))
+val sgn = (if sgn < 0 then ~1 else (if sgn > 0 then 1 else 0)): int
+//
+in
+  $UN.cast{int(sgn(i-j))}(sgn)
+end // end of [compare_intinf_intinf]
+
+(* ****** ****** *)
+
+implement{}
+pow_intinf_int
+  (base, exp) = r where
+{
+//
+val r = ptr_alloc<mpz> ()
+val () = $GMP.mpz_init (!(r.2))
+val () = $GMP.mpz_pow_uint (!(r.2), !(base.2), i2u(exp))
+//
+} (* end of [pow_intinf_int] *)
+
+(* ****** ****** *)
+
+end // end of [local]
+
+(* ****** ****** *)
+
+implement{}
+print_intinf (x) = fprint_intinf (stdout_ref, x)
+implement{}
+prerr_intinf (x) = fprint_intinf (stderr_ref, x)
+implement{}
+fprint_intinf (out, x) = fprint_intinf_base (out, x, 10(*base*))
+
+(* ****** ****** *)
+
+(* end of [intinf_vt.dats] *)
diff --git a/samples/ATS/linset_listord.dats b/samples/ATS/linset_listord.dats
deleted file mode 100644
index eb7dd642..00000000
--- a/samples/ATS/linset_listord.dats
+++ /dev/null
@@ -1,504 +0,0 @@
-(***********************************************************************)
-(*                                                                     *)
-(*                         Applied Type System                         *)
-(*                                                                     *)
-(***********************************************************************)
-
-(*
-** ATS/Postiats - Unleashing the Potential of Types!
-** Copyright (C) 2011-2013 Hongwei Xi, ATS Trustful Software, Inc.
-** All rights reserved
-**
-** ATS is free software;  you can  redistribute it and/or modify it under
-** the terms of  the GNU GENERAL PUBLIC LICENSE (GPL) as published by the
-** Free Software Foundation; either version 3, or (at  your  option)  any
-** later version.
-** 
-** ATS is distributed in the hope that it will be useful, but WITHOUT ANY
-** WARRANTY; without  even  the  implied  warranty  of MERCHANTABILITY or
-** FITNESS FOR A PARTICULAR PURPOSE.  See the  GNU General Public License
-** for more details.
-** 
-** You  should  have  received  a  copy of the GNU General Public License
-** along  with  ATS;  see the  file COPYING.  If not, please write to the
-** Free Software Foundation,  51 Franklin Street, Fifth Floor, Boston, MA
-** 02110-1301, USA.
-*)
-
-(* ****** ****** *)
-
-(* Author: Hongwei Xi *)
-(* Authoremail: hwxi AT cs DOT bu DOT edu *)
-(* Start time: February, 2013 *)
-
-(* ****** ****** *)
-//
-// HX-2013-08:
-// a set is represented as a sorted list in descending order;
-// note that descending order is chosen to faciliate set comparison
-//
-(* ****** ****** *)
-
-staload
-UN = "prelude/SATS/unsafe.sats"
-
-(* ****** ****** *)
-
-staload "libats/SATS/linset_listord.sats"
-
-(* ****** ****** *)
-
-#include "./SHARE/linset.hats" // code reuse
-#include "./SHARE/linset_node.hats" // code reuse
-
-(* ****** ****** *)
-
-assume
-set_vtype (elt:t@ype) = List0_vt (elt)
-
-(* ****** ****** *)
-
-implement{}
-linset_nil () = list_vt_nil ()
-implement{}
-linset_make_nil () = list_vt_nil ()
-
-(* ****** ****** *)
-
-implement
-{a}(*tmp*)
-linset_sing
-  (x) = list_vt_cons{a}(x, list_vt_nil)
-// end of [linset_sing]
-implement{a}
-linset_make_sing
-  (x) = list_vt_cons{a}(x, list_vt_nil)
-// end of [linset_make_sing]
-
-(* ****** ****** *)
-
-implement{}
-linset_is_nil (xs) = list_vt_is_nil (xs)
-implement{}
-linset_isnot_nil (xs) = list_vt_is_cons (xs)
-
-(* ****** ****** *)
-
-implement{a}
-linset_size (xs) =
-  let val n = list_vt_length(xs) in i2sz(n) end
-// end of [linset_size]
-
-(* ****** ****** *)
-
-implement{a}
-linset_is_member
-  (xs, x0) = let
-//
-fun aux
-  {n:nat} .<n>.
-(
-  xs: !list_vt (a, n)
-) :<> bool = let
-in
-//
-case+ xs of
-| list_vt_cons (x, xs) => let
-    val sgn = compare_elt_elt<a> (x0, x) in
-    if sgn > 0 then false else (if sgn < 0 then aux (xs) else true)
-  end // end of [list_vt_cons]
-| list_vt_nil ((*void*)) => false
-//
-end // end of [aux]
-//
-in
-  aux (xs)
-end // end of [linset_is_member]
-
-(* ****** ****** *)
-
-implement{a}
-linset_copy (xs) = list_vt_copy<a> (xs)
-implement{a}
-linset_free (xs) = list_vt_free<a> (xs)
-
-(* ****** ****** *)
-
-implement{a}
-linset_insert
-  (xs, x0) = let
-//
-fun
-mynode_cons
-  {n:nat} .<>.
-(
-  nx: mynode1 (a), xs: list_vt (a, n)
-) : list_vt (a, n+1) = let
-//
-val xs1 =
-$UN.castvwtp0{List1_vt(a)}(nx)
-val+@list_vt_cons (_, xs2) = xs1
-prval () = $UN.cast2void (xs2); val () = (xs2 := xs)
-//
-in
-  fold@ (xs1); xs1
-end // end of [mynode_cons]
-//
-fun ins
-  {n:nat} .<n>. // tail-recursive
-(
-  xs: &list_vt (a, n) >> list_vt (a, n1)
-) : #[n1:nat | n <= n1; n1 <= n+1] bool =
-(
-case+ xs of
-| @list_vt_cons
-    (x, xs1) => let
-    val sgn =
-      compare_elt_elt<a> (x0, x)
-    // end of [val]
-  in
-    if sgn > 0 then let
-      prval () = fold@ (xs)
-      val nx = mynode_make_elt<a> (x0)
-      val ((*void*)) = xs := mynode_cons (nx, xs)
-    in
-      false
-    end else if sgn < 0 then let
-      val ans = ins (xs1)
-      prval () = fold@ (xs)
-    in
-      ans
-    end else let // [x0] is found
-      prval () = fold@ (xs)
-    in
-      true (* [x0] in [xs] *)
-    end (* end of [if] *)
-  end // end of [list_vt_cons]
-| list_vt_nil () => let
-    val nx = mynode_make_elt<a> (x0)
-    val ((*void*)) = xs := mynode_cons (nx, xs)
-  in
-    false
-  end // end of [list_vt_nil]
-) (* end of [ins] *)
-//
-in
-  $effmask_all (ins (xs))
-end // end of [linset_insert]
-
-(* ****** ****** *)
-
-(*
-//
-HX-2013-08:
-[linset_remove] moved up
-//
-implement{a}
-linset_remove
-  (xs, x0) = let
-//
-fun rem
-  {n:nat} .<n>. // tail-recursive
-(
-  xs: &list_vt (a, n) >> list_vt (a, n1)
-) : #[n1:nat | n1 <= n; n <= n1+1] bool =
-(
-case+ xs of
-| @list_vt_cons
-    (x, xs1) => let
-    val sgn =
-      compare_elt_elt<a> (x0, x)
-    // end of [val]
-  in
-    if sgn > 0 then let
-      prval () = fold@ (xs)
-    in
-      false
-    end else if sgn < 0 then let
-      val ans = rem (xs1)
-      prval () = fold@ (xs)
-    in
-      ans
-    end else let // x0 = x
-      val xs1_ = xs1
-      val ((*void*)) = free@{a}{0}(xs)
-      val () = xs := xs1_
-    in
-      true // [x0] in [xs]
-    end (* end of [if] *)
-  end // end of [list_vt_cons]
-| list_vt_nil () => false
-) (* end of [rem] *)
-//
-in
-  $effmask_all (rem (xs))
-end // end of [linset_remove]
-*)
-
-(* ****** ****** *)
-(*
-** By Brandon Barker
-*)
-implement
-{a}(*tmp*)
-linset_choose
-  (xs, x0) = let
-in
-//
-case+ xs of
-| list_vt_cons
-    (x, xs1) => let
-    val () = x0 := x
-    prval () = opt_some{a}(x0)
-  in
-    true
-  end // end of [list_vt_cons]
-| list_vt_nil () => let
-    prval () = opt_none{a}(x0)
-  in
-    false
-  end // end of [list_vt_nil]
-//
-end // end of [linset_choose]
-
-(* ****** ****** *)
-
-implement
-{a}{env}
-linset_foreach_env (xs, env) = let
-//
-implement
-list_vt_foreach$fwork<a><env>
-  (x, env) = linset_foreach$fwork<a><env> (x, env)
-//
-in
-  list_vt_foreach_env<a><env> (xs, env)
-end // end of [linset_foreach_env]
-
-(* ****** ****** *)
-
-implement{a}
-linset_listize (xs) = xs
-
-(* ****** ****** *)
-
-implement{a}
-linset_listize1 (xs) = list_vt_copy (xs)
-
-(* ****** ****** *)
-//
-// HX: functions for processing mynodes
-//
-(* ****** ****** *)
-
-implement{
-} mynode_null{a} () =
-  $UN.castvwtp0{mynode(a,null)}(the_null_ptr)
-// end of [mynode_null]
-
-(* ****** ****** *)
-
-implement
-{a}(*tmp*)
-mynode_make_elt
-  (x) = let
-//
-val nx = list_vt_cons{a}{0}(x, _ )
-//
-in
-  $UN.castvwtp0{mynode1(a)}(nx)
-end // end of [mynode_make_elt]
-
-(* ****** ****** *)
-
-implement{
-} mynode_free
-  {a}(nx) = () where {
-val nx =
-  $UN.castvwtp0{List1_vt(a)}(nx)
-//
-val+~list_vt_cons (_, nx2) = nx
-//
-prval ((*void*)) = $UN.cast2void (nx2)
-//
-} (* end of [mynode_free] *)
-
-(* ****** ****** *)
-
-implement
-{a}(*tmp*)
-mynode_get_elt
-  (nx) = (x) where {
-//
-val nx1 =
-  $UN.castvwtp1{List1_vt(a)}(nx)
-//
-val+list_vt_cons (x, _) = nx1
-//
-prval ((*void*)) = $UN.cast2void (nx1)
-//
-} (* end of [mynode_get_elt] *)
-
-(* ****** ****** *)
-
-implement
-{a}(*tmp*)
-mynode_set_elt
-  {l} (nx, x0) =
-{
-//
-val nx1 =
-  $UN.castvwtp1{List1_vt(a)}(nx)
-//
-val+@list_vt_cons (x, _) = nx1
-//
-val () = x := x0
-//
-prval () = fold@ (nx1)
-prval () = $UN.cast2void (nx1)
-//
-prval () = __assert (nx) where
-{
-  extern praxi __assert (nx: !mynode(a?, l) >> mynode (a, l)): void
-} (* end of [prval] *)
-//
-} (* end of [mynode_set_elt] *)
-
-(* ****** ****** *)
-
-implement
-{a}(*tmp*)
-mynode_getfree_elt
-  (nx) = (x) where {
-//
-val nx =
-  $UN.castvwtp0{List1_vt(a)}(nx)
-//
-val+~list_vt_cons (x, nx2) = nx
-//
-prval ((*void*)) = $UN.cast2void (nx2)
-//
-} (* end of [mynode_getfree_elt] *)
-
-(* ****** ****** *)
-
-(*
-fun{a:t0p}
-linset_takeout_ngc
-  (set: &set(INV(a)) >> _, x0: a):<!wrt> mynode0 (a)
-// end of [linset_takeout_ngc]
-*)
-implement
-{a}(*tmp*)
-linset_takeout_ngc
-  (set, x0) = let
-//
-fun takeout
-(
-  xs: &List0_vt (a) >> _
-) : mynode0(a) = let
-in
-//
-case+ xs of
-| @list_vt_cons
-    (x, xs1) => let
-    prval pf_x = view@x
-    prval pf_xs1 = view@xs1
-    val sgn =
-      compare_elt_elt<a> (x0, x)
-    // end of [val]
-  in
-    if sgn > 0 then let
-      prval () = fold@ (xs)
-    in
-      mynode_null{a}((*void*))
-    end else if sgn < 0 then let
-      val res = takeout (xs1)
-      prval ((*void*)) = fold@ (xs)
-    in
-      res
-    end else let // x0 = x
-      val xs1_ = xs1
-      val res = $UN.castvwtp0{mynode1(a)}((pf_x, pf_xs1 | xs))
-      val () = xs := xs1_
-    in
-      res // [x0] in [xs]
-    end (* end of [if] *)
-  end // end of [list_vt_cons]
-| list_vt_nil () => mynode_null{a}((*void*))
-//
-end (* end of [takeout] *)
-//
-in
-  $effmask_all (takeout (set))
-end // end of [linset_takeout_ngc]
-
-(* ****** ****** *)
-
-implement
-{a}(*tmp*)
-linset_takeoutmax_ngc
-  (xs) = let
-in
-//
-case+ xs of
-| @list_vt_cons
-    (x, xs1) => let
-    prval pf_x = view@x
-    prval pf_xs1 = view@xs1
-    val xs_ = xs
-    val () = xs := xs1
-  in
-    $UN.castvwtp0{mynode1(a)}((pf_x, pf_xs1 | xs_))
-  end // end of [list_vt_cons]
-| @list_vt_nil () => let
-    prval () = fold@ (xs)
-  in
-    mynode_null{a}((*void*))
-  end // end of [list_vt_nil]
-//
-end // end of [linset_takeoutmax_ngc]
-
-(* ****** ****** *)
-
-implement
-{a}(*tmp*)
-linset_takeoutmin_ngc
-  (xs) = let
-//
-fun unsnoc
-  {n:pos} .<n>.
-(
-  xs: &list_vt (a, n) >> list_vt (a, n-1)
-) :<!wrt> mynode1 (a) = let
-//
-val+@list_vt_cons (x, xs1) = xs
-//
-prval pf_x = view@x and pf_xs1 = view@xs1
-//
-in
-//
-case+ xs1 of
-| list_vt_cons _ =>
-    let val res = unsnoc(xs1) in fold@xs; res end
-  // end of [list_vt_cons]
-| list_vt_nil () => let
-    val xs_ = xs
-    val () = xs := list_vt_nil{a}()
-  in
-    $UN.castvwtp0{mynode1(a)}((pf_x, pf_xs1 | xs_))
-  end // end of [list_vt_nil]
-//
-end // end of [unsnoc]
-//
-in
-//
-case+ xs of
-| list_vt_cons _ => unsnoc (xs)
-| list_vt_nil () => mynode_null{a}((*void*))
-//
-end // end of [linset_takeoutmin_ngc]
-
-(* ****** ****** *)
-
-(* end of [linset_listord.dats] *)
diff --git a/samples/ATS/linset_listord.sats b/samples/ATS/linset_listord.sats
deleted file mode 100644
index 468a534f..00000000
--- a/samples/ATS/linset_listord.sats
+++ /dev/null
@@ -1,51 +0,0 @@
-(***********************************************************************)
-(*                                                                     *)
-(*                         Applied Type System                         *)
-(*                                                                     *)
-(***********************************************************************)
-
-(*
-** ATS/Postiats - Unleashing the Potential of Types!
-** Copyright (C) 2011-2013 Hongwei Xi, ATS Trustful Software, Inc.
-** All rights reserved
-**
-** ATS is free software;  you can  redistribute it and/or modify it under
-** the terms of  the GNU GENERAL PUBLIC LICENSE (GPL) as published by the
-** Free Software Foundation; either version 3, or (at  your  option)  any
-** later version.
-** 
-** ATS is distributed in the hope that it will be useful, but WITHOUT ANY
-** WARRANTY; without  even  the  implied  warranty  of MERCHANTABILITY or
-** FITNESS FOR A PARTICULAR PURPOSE.  See the  GNU General Public License
-** for more details.
-** 
-** You  should  have  received  a  copy of the GNU General Public License
-** along  with  ATS;  see the  file COPYING.  If not, please write to the
-** Free Software Foundation,  51 Franklin Street, Fifth Floor, Boston, MA
-** 02110-1301, USA.
-*)
-
-(* ****** ****** *)
-//
-// Author: Hongwei Xi
-// Authoremail: hwxiATcsDOTbuDOTedu
-// Time: October, 2010
-//
-(* ****** ****** *)
-
-#define ATS_PACKNAME "ATSLIB.libats.linset_listord"
-#define ATS_STALOADFLAG 0 // no static loading at run-time
-
-(* ****** ****** *)
-
-#include "./SHARE/linset.hats"
-#include "./SHARE/linset_node.hats"
-
-(* ****** ****** *)
-
-castfn
-linset2list {a:t0p} (xs: set (INV(a))):<> List0_vt (a)
-
-(* ****** ****** *)
-
-(* end of [linset_listord.sats] *)