From: Heesob Park <phasis@...>
Date: 2009-03-02T22:51:50+09:00
Subject: [ruby-core:22623] Re: suggestions for float

> From: Yukihiro Matsumoto <matz@ruby-lang.org>
> To: ruby-core@ruby-lang.org
> Date: Mon, 2 Mar 2009 19:46:27 +0900
> Subject: [ruby-core:22621] Re: suggestions for float
> Hi,
>
> In message "Re: [ruby-core:22595] Re: suggestions for float"
>    on Sun, 1 Mar 2009 01:22:29 +0900, Roger Pack <rogerdpack@gmail.com> writes:
>
> |I guess there's not too much feedback on this one :)
>
> We are not ignoring you.  We just lack for resource working on the
> proposal right now.  We welcome a patch to make
>
>  some_float == eval("#{some_float}")
>
> to be always true.

Lua do the job as following definition:

#define LUA_NUMBER_FMT		"%.14g"
#define lua_number2str(s,n)	sprintf((s), LUA_NUMBER_FMT, (n))
#define lua_str2number(s,p)	strtod((s), (p))

In my test with ruby float, %.14g is not enough, %.20g is suitable.
It will written with Ruby code as like this:

string = ('%.20g.0' % some_float).sub(/(\.\d+)(\.0)$/,'\1')

some_float == eval(string)

Regards,

Park Heesob