Re: simple question about NaN and FP exceptions

[Tony Finch <dot@...>]

On Mon, 21 Feb 2011, Axel Kittenberger wrote:
>
> Would it be too much compatibility breaking or performance impacting
> to have NaN evaluate itself to boolean false instead of true by
> default?

Try it :-)

Note that there is a luai_numisnan() macro defined in luaconf.h but it
takes the Lua context pointer as an argument so I could not use it here.

--- a/src/lobject.h
+++ b/src/lobject.h
@@ -121,7 +121,7 @@ typedef struct lua_TValue {
 #define bvalue(o)      check_exp(ttisboolean(o), (o)->value_.b)
 #define thvalue(o)     check_exp(ttisthread(o), &(o)->value_.gc->th)

-#define l_isfalse(o)   (ttisnil(o) || (ttisboolean(o) && bvalue(o) == 0))
+#define l_isfalse(o)   (ttisnil(o) || (ttisboolean(o) && bvalue(o) == 0) || (ttisnumber(o) && !luai_numeq((o),(o))))


 #define iscollectable(o)       (ttype(o) >= LUA_TSTRING)

Tony.
-- 
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