From 46f607ae233a8f71c09d40dd45aae5f2ec7056fc Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Tue, 11 Sep 2012 19:28:52 -0700
Subject: * eval.c (eval_init): new instrinsic function /= registered.

* lib.c (numneqv): New function.

* lib.h (numneqv): Declared.

* txr.1: New function documented.
---
 ChangeLog | 10 ++++++++++
 eval.c    |  1 +
 lib.c     | 12 ++++++++++++
 lib.h     |  1 +
 txr.1     | 15 +++++++++++++++
 5 files changed, 39 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index dad71696..708bf2c3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2012-09-11  Kaz Kylheku  <kaz@kylheku.com>
+
+	* eval.c (eval_init): new instrinsic function /= registered.
+
+	* lib.c (numneqv): New function.
+
+	* lib.h (numneqv): Declared.
+
+	* txr.1: New function documented.
+
 2012-09-10  Kaz Kylheku  <kaz@kylheku.com>
 
 	* match.c (v_collect): Bug in processing of @(last) directive.
diff --git a/eval.c b/eval.c
index 5ef0f34e..9266846b 100644
--- a/eval.c
+++ b/eval.c
@@ -2228,6 +2228,7 @@ void eval_init(void)
   reg_fun(intern(lit(">="), user_package), func_n1v(gev));
   reg_fun(intern(lit("<="), user_package), func_n1v(lev));
   reg_fun(intern(lit("="), user_package), func_n1v(numeqv));
+  reg_fun(intern(lit("/="), user_package), func_n0v(numneqv));
   reg_fun(intern(lit("max"), user_package), func_n1v(maxv));
   reg_fun(intern(lit("min"), user_package), func_n1v(minv));
 
diff --git a/lib.c b/lib.c
index 74e64a90..8492c3dc 100644
--- a/lib.c
+++ b/lib.c
@@ -1414,6 +1414,18 @@ val numeqv(val first, val rest)
   return t;
 }
 
+val numneqv(val list)
+{
+  val i, j;
+
+  for (i = list; i; i = cdr(i))
+    for (j = cdr(i); j; j = cdr(j))
+      if (numeq(car(i), car(j)))
+        return nil;
+
+  return t;
+}
+
 val max2(val anum, val bnum)
 {
   return if3(ge(anum, bnum), anum, bnum);
diff --git a/lib.h b/lib.h
index eedaa1cb..d454fd29 100644
--- a/lib.h
+++ b/lib.h
@@ -450,6 +450,7 @@ val ltv(val first, val rest);
 val gev(val first, val rest);
 val lev(val first, val rest);
 val numeqv(val first, val rest);
+val numneqv(val list);
 val max2(val anum, val bnum);
 val min2(val anum, val bnum);
 val maxv(val first, val rest);
diff --git a/txr.1 b/txr.1
index 6323f6a9..c4ede065 100644
--- a/txr.1
+++ b/txr.1
@@ -8377,6 +8377,21 @@ undergo two different conversions.  For instance in (< <float> <character>
 its Unicode, and if that comparison suceeds, then in the second comparison, the
 character will convert to integer.
 
+.SS Function /=
+
+.TP
+Syntax:
+
+  (/= <number>*)
+
+.TP
+Description:
+
+The arguments to /= may be numbers or characters.  The /= function returns t if
+no two of its arguments are numerically equal. That is to say, if there exist
+some a and b which are distinct arguments such that (= a b) is true, then
+teh function returns nil. Otherwise it returns t.
+
 .SS Functions max and min
 
 .TP
-- 
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