[PPL-devel] [GIT] ppl/ppl(master): Added Prolog_get_nil() and Prolog_put_nil().

[Roberto Bagnara]

Module: ppl/ppl
Branch: master
Commit: 382be0e6948d88ea54482025a7226f61e26aebde
URL:    http://www.cs.unipr.it/git/gitweb.cgi?p=ppl/ppl.git;a=commit;h=382be0e6948d88ea54482025a7226f61e26aebde

Author: Roberto Bagnara <roberto.bagnara at bugseng.com>
Date:   Sat Mar 29 11:04:25 2014 +0100

Added Prolog_get_nil() and Prolog_put_nil().

---

 interfaces/Prolog/GNU/gprolog_cfli.hh |   25 +++++++++++++++++++++++++
 1 files changed, 25 insertions(+), 0 deletions(-)

diff --git a/interfaces/Prolog/GNU/gprolog_cfli.hh b/interfaces/Prolog/GNU/gprolog_cfli.hh
index 2c4c64f..f6bddd1 100644
--- a/interfaces/Prolog/GNU/gprolog_cfli.hh
+++ b/interfaces/Prolog/GNU/gprolog_cfli.hh
@@ -252,6 +252,16 @@ Prolog_construct_cons(Prolog_term_ref& c,
 }
 
 /*!
+  Assign to \p t the list terminator <CODE>[]</CODE> (which needs not
+  be an atom).
+*/
+inline int
+Prolog_put_nil(Prolog_term_ref& t) {
+  t = Mk_Atom(atom_nil);
+  return 1;
+}
+
+/*!
   Assign to \p t a term representing the address contained in \p p.
 */
 inline int
@@ -432,6 +442,21 @@ Prolog_get_arg(int i, Prolog_term_ref t, Prolog_term_ref& a) {
 }
 
 /*!
+  Succeeds if and only if \p t represents the list terminator <CODE>[]</CODE>
+  (which needs not be an atom).
+*/
+inline int
+Prolog_get_nil(Prolog_term_ref t) {
+  if (Blt_Atom(t) == FALSE) {
+    return 0;
+  }
+  else {
+    int a = atom_nil;
+    return Rd_Atom_Check(t) == a;
+  }
+}
+
+/*!
   If \p c is a Prolog cons (list constructor), assign its head and
   tail to \p h and \p t, respectively.
   The behavior is undefined if \p c is not a Prolog cons.