Change comparison functions =, <, >, <=, >= to take many arguments.

* src/data.c: Change comparison functions' interface and
  implementation
* src/lisp.h: Make arithcompare available for efficient two arg
  comparisons
* src/bytecode.c: Use arithcompare
* src/fileio.c: Use new interface
* test/automated/data-tests.el: New tests for comparison functions
* etc/NEWS

4 files changed, 59 insertions, 38 deletions

diff --git a/src/bytecode.c b/src/bytecode.c
index e0e7b22ea13..3ac8b452fbe 100644
--- a/src/bytecode.c
+++ b/src/bytecode.c
@@ -1367,7 +1367,7 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
             Lisp_Object v1;
             BEFORE_POTENTIAL_GC ();
             v1 = POP;
-            TOP = Fgtr (TOP, v1);
+            TOP = arithcompare (TOP, v1, ARITH_GRTR);
             AFTER_POTENTIAL_GC ();
             NEXT;
           }
@@ -1377,7 +1377,7 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
             Lisp_Object v1;
             BEFORE_POTENTIAL_GC ();
             v1 = POP;
-            TOP = Flss (TOP, v1);
+            TOP = arithcompare (TOP, v1, ARITH_LESS);
             AFTER_POTENTIAL_GC ();
             NEXT;
           }
@@ -1387,7 +1387,7 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
             Lisp_Object v1;
             BEFORE_POTENTIAL_GC ();
             v1 = POP;
-            TOP = Fleq (TOP, v1);
+            TOP = arithcompare (TOP, v1, ARITH_LESS_OR_EQUAL);
             AFTER_POTENTIAL_GC ();
             NEXT;
           }
@@ -1397,7 +1397,7 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
             Lisp_Object v1;
             BEFORE_POTENTIAL_GC ();
             v1 = POP;
-            TOP = Fgeq (TOP, v1);
+            TOP = arithcompare (TOP, v1, ARITH_GRTR_OR_EQUAL);
             AFTER_POTENTIAL_GC ();
             NEXT;
           }
diff --git a/src/data.c b/src/data.c
index 9f4bd1f1c02..7f28028f604 100644
--- a/src/data.c
+++ b/src/data.c
@@ -2255,10 +2255,8 @@ bool-vector.  IDX starts at 0.  */)
 
 /* Arithmetic functions */
 
-enum comparison { equal, notequal, less, grtr, less_or_equal, grtr_or_equal };
-
-static Lisp_Object
-arithcompare (Lisp_Object num1, Lisp_Object num2, enum comparison comparison)
+Lisp_Object
+arithcompare (Lisp_Object num1, Lisp_Object num2, enum Arith_Comparison comparison)
 {
   double f1 = 0, f2 = 0;
   bool floatp = 0;
@@ -2275,32 +2273,32 @@ arithcompare (Lisp_Object num1, Lisp_Object num2, enum comparison comparison)
 
   switch (comparison)
     {
-    case equal:
+    case ARITH_EQUAL:
       if (floatp ? f1 == f2 : XINT (num1) == XINT (num2))
         return Qt;
       return Qnil;
 
-    case notequal:
+    case ARITH_NOTEQUAL:
       if (floatp ? f1 != f2 : XINT (num1) != XINT (num2))
         return Qt;
       return Qnil;
 
-    case less:
+    case ARITH_LESS:
       if (floatp ? f1 < f2 : XINT (num1) < XINT (num2))
         return Qt;
       return Qnil;
 
-    case less_or_equal:
+    case ARITH_LESS_OR_EQUAL:
       if (floatp ? f1 <= f2 : XINT (num1) <= XINT (num2))
         return Qt;
       return Qnil;
 
-    case grtr:
+    case ARITH_GRTR:
       if (floatp ? f1 > f2 : XINT (num1) > XINT (num2))
         return Qt;
       return Qnil;
 
-    case grtr_or_equal:
+    case ARITH_GRTR_OR_EQUAL:
       if (floatp ? f1 >= f2 : XINT (num1) >= XINT (num2))
         return Qt;
       return Qnil;
@@ -2310,48 +2308,60 @@ arithcompare (Lisp_Object num1, Lisp_Object num2, enum comparison comparison)
     }
 }
 
-DEFUN ("=", Feqlsign, Seqlsign, 2, 2, 0,
-       doc: /* Return t if two args, both numbers or markers, are equal.  */)
-  (register Lisp_Object num1, Lisp_Object num2)
+static Lisp_Object
+arithcompare_driver (ptrdiff_t nargs, Lisp_Object *args,
+                     enum Arith_Comparison comparison)
 {
-  return arithcompare (num1, num2, equal);
+  for (ptrdiff_t argnum = 1; argnum < nargs; ++argnum)
+    {
+      if (EQ (Qnil, arithcompare (args[argnum-1], args[argnum], comparison)))
+        return Qnil;
+    }
+  return Qt;
 }
 
-DEFUN ("<", Flss, Slss, 2, 2, 0,
-       doc: /* Return t if first arg is less than second arg.  Both must be numbers or markers.  */)
-  (register Lisp_Object num1, Lisp_Object num2)
+DEFUN ("=", Feqlsign, Seqlsign, 1, MANY, 0,
+       doc: /* Return t if args, all numbers or markers, are equal.  */)
+  (ptrdiff_t nargs, Lisp_Object *args)
 {
-  return arithcompare (num1, num2, less);
+  return arithcompare_driver (nargs, args, ARITH_EQUAL);
 }
 
-DEFUN (">", Fgtr, Sgtr, 2, 2, 0,
-       doc: /* Return t if first arg is greater than second arg.  Both must be numbers or markers.  */)
-  (register Lisp_Object num1, Lisp_Object num2)
+DEFUN ("<", Flss, Slss, 1, MANY, 0,
+       doc: /* Return t if each arg is less than the next arg.  All must be numbers or markers.  */)
+  (ptrdiff_t nargs, Lisp_Object *args)
 {
-  return arithcompare (num1, num2, grtr);
+  return arithcompare_driver (nargs, args, ARITH_LESS);
 }
 
-DEFUN ("<=", Fleq, Sleq, 2, 2, 0,
-       doc: /* Return t if first arg is less than or equal to second arg.
-Both must be numbers or markers.  */)
-  (register Lisp_Object num1, Lisp_Object num2)
+DEFUN (">", Fgtr, Sgtr, 1, MANY, 0,
+       doc: /* Return t if each arg is greater than the next arg.  All must be numbers or markers.  */)
+  (ptrdiff_t nargs, Lisp_Object *args)
 {
-  return arithcompare (num1, num2, less_or_equal);
+  return arithcompare_driver (nargs, args, ARITH_GRTR);
 }
 
-DEFUN (">=", Fgeq, Sgeq, 2, 2, 0,
-       doc: /* Return t if first arg is greater than or equal to second arg.
-Both must be numbers or markers.  */)
-  (register Lisp_Object num1, Lisp_Object num2)
+DEFUN ("<=", Fleq, Sleq, 1, MANY, 0,
+       doc: /* Return t if each arg is less than or equal to the next arg.
+All must be numbers or markers.  */)
+  (ptrdiff_t nargs, Lisp_Object *args)
+{
+  return arithcompare_driver (nargs, args, ARITH_LESS_OR_EQUAL);
+}
+
+DEFUN (">=", Fgeq, Sgeq, 1, MANY, 0,
+       doc: /* Return t if each arg is greater than or equal to the next arg.
+All must be numbers or markers.  */)
+  (ptrdiff_t nargs, Lisp_Object *args)
 {
-  return arithcompare (num1, num2, grtr_or_equal);
+  return arithcompare_driver (nargs, args, ARITH_GRTR_OR_EQUAL);
 }
 
 DEFUN ("/=", Fneq, Sneq, 2, 2, 0,
        doc: /* Return t if first arg is not equal to second arg.  Both must be numbers or markers.  */)
   (register Lisp_Object num1, Lisp_Object num2)
 {
-  return arithcompare (num1, num2, notequal);
+  return arithcompare (num1, num2, ARITH_NOTEQUAL);
 }
 
 DEFUN ("zerop", Fzerop, Szerop, 1, 1, 0,
diff --git a/src/fileio.c b/src/fileio.c
index 0e6113f349d..1a2bdfa237c 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -5121,7 +5121,8 @@ DEFUN ("car-less-than-car", Fcar_less_than_car, Scar_less_than_car, 2, 2, 0,
        doc: /* Return t if (car A) is numerically less than (car B).  */)
   (Lisp_Object a, Lisp_Object b)
 {
-  return Flss (Fcar (a), Fcar (b));
+  Lisp_Object args[2] = { Fcar (a), Fcar (b), };
+  return Flss (2, args);
 }
 
 /* Build the complete list of annotations appropriate for writing out
diff --git a/src/lisp.h b/src/lisp.h
index 38b538d9bc2..2b1af1faa19 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -3160,6 +3160,16 @@ EXFUN (Fbyteorder, 0) ATTRIBUTE_CONST;
 /* Defined in data.c.  */
 extern Lisp_Object indirect_function (Lisp_Object);
 extern Lisp_Object find_symbol_value (Lisp_Object);
+enum Arith_Comparison {
+  ARITH_EQUAL,
+  ARITH_NOTEQUAL,
+  ARITH_LESS,
+  ARITH_GRTR,
+  ARITH_LESS_OR_EQUAL,
+  ARITH_GRTR_OR_EQUAL
+};
+extern Lisp_Object arithcompare (Lisp_Object num1, Lisp_Object num2,
+                                 enum Arith_Comparison comparison);
 
 /* Convert the integer I to an Emacs representation, either the integer
    itself, or a cons of two or three integers, or if all else fails a float.