Re: number question

["Nick Trout" <nick@...>]

I use float as well, havent needed double yet. Erm, could tolua be modified as
well, double is hard coded into that everywhere. It's a great tool just have
that one niggle!

----- Original Message -----
From: "Ralf HECKHAUSEN" <RHeckhau@frequentis.com>
To: "Multiple recipients of list" <lua-l@tecgraf.puc-rio.br>
Sent: Tuesday, April 18, 2000 2:23 PM
Subject: Re: number question


> This would be also my favorite solution, having two independent number types.
My software floating point emulation slows down the execution unacceptable, but
I need double numbers to make use of LuaOrb. I am just in the process of doing
an implementation of integer numbers through tag methods on userdata, but I
wonder what will be the costs of it compared with a direct long number type.
> Ralf
>
> >>> john@glowingslab.com 04/18/00 10:17am >>>
> If there are only a few, well-known changes that are required to enable Lua
> to use longs, why don't you change the main source code to support it
> automatically?  Sounds like you could apply the changes you mention with a
> few #defines/#ifdefs.
>
> I expect that if you added explicit support for "float" and "long", you'd
> cover the vast majority of people who wanted a different number type.  And
> it would save you having to write a technical note!  :-)
>
> john
>
> -----Original Message-----
> From: Luiz Henrique de Figueiredo To: Multiple recipients of list
> <lua-l@tecgraf.puc-rio.br>
> Date: 17 April 2000 17:26
> Subject: Re: number question
>
>
> >>From: "Ralf HECKHAUSEN" <RHeckhau@frequentis.com>
> >
> >>We want to run Lua on an machine without floating-point-unit and basically
> only need integer numbers. How much effort is it to switch the number type
> to long instead of double?
> >
> >Not much effort really.
> >The simplest solution is just to choose -DLUA_NUM_TYPE=long in config.
> >This should compile without problems, although it will still %g in sprintf
> >for converting numbers to string.
> >Moreover, the lexer will still use floating-point arithmetic to read
> numbers
> >from Lua programs.
> >If you really want *no* floating-point arithmetic at all, then you need to
> go
> >through the code and look for all places marked "LUA_NUMBER" and then
> remove
> >the floating-point arithmetic.
> >For Lua 3.2, these places are:
> >
> > lobject.c:double luaO_str2d (char *s) {  /* LUA_NUMBER */
> > lvm.c:int luaV_tonumber (TObject *obj) {  /* LUA_NUMBER */
> > lvm.c:int luaV_tostring (TObject *obj) {  /* LUA_NUMBER */
> > lundump.h:#define NUMBER_FMT      "%.16g"         /* LUA_NUMBER */
> >
> >plus the "fraction:" loop in llex.c.
> >You may want to change the API to use longs intead of doubles too.
> >
> > lapi.c:double lua_getnumber (lua_Object object)
> > lapi.c:void lua_pushnumber (double n)
> > lauxlib.c:double luaL_check_number (int numArg)
> > lauxlib.c:double luaL_opt_number (int numArg, double def)
> >
> >and the corresponding declarations in lua.h and lauxlib.h.
> >
> >I plan to write a Lua Technical Note about this when I find the time.
> >
> >>Is it possible to have a new user type float next to number with all
> standard operators? Did someone already implement this?
> >
> >You could implement those using tag methods on userdata.
> >--lhf
> >
>
>