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- Subject: Re: Large number bytecode weirdness on different platforms
- From: Mike Pall <mikelu-0701@...>
- Date: Tue, 30 Jan 2007 02:17:19 +0100
Hi,
Rici Lake wrote:
> On 29-Jan-07, at 5:12 PM, Mike Pall wrote:
> >The behaviour of number parsing and output is system dependent
> >because Lua uses the library functions provided by the toolchain.
> >This makes sense because some implementations need more lines of
> >code for this task than Lua itself. ;-)
>
> OK, it's a little longer than I hoped it might be (127 including
> comments and test driver / 72 actually in the function) but it's still
> somewhat smaller than Lua. Of course, it only does hex floats (doubles,
> actually, but a simple %s/double/float/g should fix that.)
One of my ancient patches for Lua 5.1alpha has a 10-liner which
handles non-fractional hex-numbers with full lua_Number
precision. This is probably sufficient for the OP:
http://lua-users.org/lists/lua-l/2005-09/msg00158.html
Just to put the quoted statement in context: I was referring to
the inherent difficulty of parsing and printing of _decimal_
numbers to/from binary floating-point representations. This needs
much more code. If anyone has ever wondered why glibc includes
lots of GMP functions, here's the reason:
http://lua-users.org/lists/lua-l/2004-12/msg00041.html
Bye,
Mike