From ad7a6f7bc7b58097fb6c456709c9a9b1aee0487b Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Wed, 16 Aug 2017 06:54:33 -0700
Subject: Allow character inputs in some bit operations.

* arith.c (logand, logior, logxor): Allow one operand to be a
character, if the opposite opernad is a fixnum integer.
The result is a character.
(bit): Allow the value being tested to be a character.

* txr.1: Updated.
---
 arith.c | 28 ++++++++++++++++++++++++++++
 txr.1   | 16 +++++++++++++++-
 2 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/arith.c b/arith.c
index 7700ea07..abf9f1be 100644
--- a/arith.c
+++ b/arith.c
@@ -2241,6 +2241,15 @@ val logand(val a, val b)
     return zero;
 
   switch (TYPE_PAIR(type(a), type(b))) {
+  case TYPE_PAIR(NUM, CHR):
+  case TYPE_PAIR(CHR, NUM):
+    if (a == b) {
+      return a;
+    } else {
+      cnum ac = c_num(a);
+      cnum bc = c_num(b);
+      return chr(ac & bc);
+    }
   case TYPE_PAIR(NUM, NUM):
     if (a == b) {
       return a;
@@ -2282,6 +2291,15 @@ val logior(val a, val b)
     return zero;
 
   switch (TYPE_PAIR(type(a), type(b))) {
+  case TYPE_PAIR(NUM, CHR):
+  case TYPE_PAIR(CHR, NUM):
+    if (a == b) {
+      return a;
+    } else {
+      cnum ac = c_num(a);
+      cnum bc = c_num(b);
+      return chr(ac | bc);
+    }
   case TYPE_PAIR(NUM, NUM):
     if (a == b) {
       return a;
@@ -2323,6 +2341,15 @@ val logxor(val a, val b)
     return zero;
 
   switch (TYPE_PAIR(type(a), type(b))) {
+  case TYPE_PAIR(NUM, CHR):
+  case TYPE_PAIR(CHR, NUM):
+    if (a == b) {
+      return a;
+    } else {
+      cnum ac = c_num(a);
+      cnum bc = c_num(b);
+      return chr(ac ^ bc);
+    }
   case TYPE_PAIR(NUM, NUM):
     if (a == b) {
       return a;
@@ -2593,6 +2620,7 @@ val bit(val a, val bit)
 
   switch (type(a)) {
   case NUM:
+  case CHR:
     {
       cnum an = c_num(a);
       if (bn < (SIZEOF_PTR * CHAR_BIT))
diff --git a/txr.1 b/txr.1
index 29195b97..a36c0f27 100644
--- a/txr.1
+++ b/txr.1
@@ -34865,6 +34865,20 @@ the value -1 (all bits 1). If
 is called with no arguments it produces
 zero. In the one-argument case, the functions just return their argument value.
 
+In the two-argument case, one of the operands may be a character, if the other
+operand is a fixnum integer. The character operand is taken to be an integer
+corresponding to the character value's Unicode code point value. The resulting
+value is regarded as a Unicode code point and converted to a character value
+accordingly.
+
+When three or more arguments are specified, the operation's semantics is
+that of a left-associative reduction through two-argument invocations,
+so that the three-argument case
+.code "(logand a b c)"
+is equivalent to the expression
+.codn "(logand (logand a b) c)" ,
+which features two two-argument cases..
+
 .coNP Function @ logtest
 .synb
 .mets (logtest < int1 << int2 )
@@ -35008,7 +35022,7 @@ and
 .desc
 The
 .code bit
-function tests whether the integer
+function tests whether the integer or character
 .meta value
 has a 1 in bit position
 .metn bit .
-- 
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