* arith.c (zerop): Handle character arguments.

(plusp, minusp): New functions.

* eval.c (eval_init): Register plusp and minusp.

* lib.h (plusp, minusp): Declared.

* txr.1: Documented plusp and minusp, and the
handling of characters by zerop.

1 files changed, 34 insertions, 0 deletions

diff --git a/arith.c b/arith.c
index 058a4e1d..365818e3 100644
--- a/arith.c
+++ b/arith.c
@@ -993,11 +993,45 @@ val zerop(val num)
     return nil;
   case FLNUM:
     return if2(c_flo(num) == 0.0, t);
+  case CHR:
+    return if2(num == chr(0), t);
   default:
     uw_throwf(error_s, lit("zerop: ~s is not a number"), num, nao);
   }
 }
 
+val plusp(val num)
+{
+  switch (type(num)) {
+  case NUM:
+    return if2(c_num(num) > 0, t);
+  case BGNUM:
+    return if2(mp_cmp_z(mp(num)) == MP_GT, t);
+  case FLNUM:
+    return if2(c_flo(num) > 0.0, t);
+  case CHR:
+    return if2(num != chr(0), t);
+  default:
+    uw_throwf(error_s, lit("plusp: ~s is not a number"), num, nao);
+  }
+}
+
+val minusp(val num)
+{
+  switch (type(num)) {
+  case NUM:
+    return if2(c_num(num) < 0, t);
+  case BGNUM:
+    return if2(mp_cmp_z(mp(num)) == MP_LT, t);
+  case FLNUM:
+    return if2(c_flo(num) < 0.0, t);
+  case CHR:
+    return nil;
+  default:
+    uw_throwf(error_s, lit("minusp: ~s is not a number"), num, nao);
+  }
+}
+
 val evenp(val num)
 {
   switch (type(num)) {