Re: [Feature Request?] __key

[Philipp Janda <siffiejoe@...>]

Am 15.07.2016 um 03:26 schröbte Coda Highland:
> On Thu, Jul 14, 2016 at 6:19 PM, Sergey Rozhenko <sergroj@gmail.com> wrote:
> > On Пт 15.07.16 2:57, Sean Conner wrote:
> > >     Oh, so to clarify (kind of making the bigint library up):
> > >
> > >          bi = require "bigint"
> > >
> > >          x = bi.make(2^128) -- syntax issues but I want something
> > >          y = bi.make(2^128) -- really really large
> > >
> > >          t = {}
> > >          t[x] = "booya!"
> > >          print(t[y])
> > >          booya!
> >
> >
> > In this case __key would help at all. With or without it you'd have to keep
> > a cache of these values, because it's needed to make __key return the same
> > object. So, it's easier to make bi.make return the same object for both
> > calls instead.
>
> That's not true at all. bi.__key could return a Lua "number"-type
> value when the value is representable without loss of precision or a
> string otherwise.

You could use the Lua "number"-type directly in the first case and a 
manually interned userdata instead of the string in the second case.

> This would provide for the nice property of
> "t[bi.make(100)] == t[100]" in addition to the "t[x] == t[y]" desired
> in the example.
>
> /s/ Adam

Philipp