Binary notation for integers: 0b[10]+

[Ico Doornekamp <lua@...>]

With proper integer support and binary operators in place in Lua 5.3, I would
like to propose something like the following to allow integers to be expressed
in binary format in Lua code as 0b[10]+:

--- lua-5.3.0-beta/src/lobject.c	2014-10-17 18:28:21.000000000 +0200
+++ lua-5.3.0-beta-ico/src/lobject.c	2014-12-01 15:13:29.557580628 +0100
@@ -280,6 +280,14 @@ static const char *l_str2int (const char
       empty = 0;
     }
   }
+  else if (s[0] == '0' &&
+      (s[1] == 'b' || s[1] == 'B')) {  /* bin? */
+    s += 2;  /* skip '0b' */
+    for (; *s == '0' || *s == '1'; s++) {
+      a = a * 2 + luaO_hexavalue(*s);
+      empty = 0;
+    }
+  }
   else {  /* decimal */
     for (; lisdigit(cast_uchar(*s)); s++) {
       a = a * 10 + luaO_hexavalue(cast_uchar(*s));


Examples:

Lua 5.3.0 (beta)  Copyright (C) 1994-2014 Lua.org, PUC-Rio
> 0b10000000
128
> 0b01
1
> 0b11111111111111111111111111111111111
34359738367

As the above patch is small and unintrusive, would inclusion in Lua 5.3 be
feasible and/or usable?

By the way, I *love* the new hexadecimal 'P' binary exponent!

-- 
:wq
^X^Cy^K^X^C^C^C^C