Re: suggestion: __typeof()

["Mark Meijer" <meijer78@...>]

Without taking a position on whether or not the __typeof metamethod feature 
should be added (I like the idea but I can't say much about what code it may 
or may not break), with regard to its return values, I think that Lua is 
more about providing flexibility and choice to their users, and less about 
enforcing polite coding behaviour. I remember reading in PiL (I think) 
something along the lines of, if you don't want to do this or this in your 
code, then simply don't do it. In this respect I think forcing the first 
return value of __typeof to be "userdata" by hardcoding it into the lua 
core, is limiting and takes away that choice from the user. Besides it's an 
extra condiion for the user to remember and deal with, which hurts the 
language's simplicity and uniformity. Just my two cents on the subject.


> From: "Michael T. Richter" <ttmrichter@gmail.com>
> Reply-To: Lua list <lua@bazar2.conectiva.com.br>
> To: Lua list <lua@bazar2.conectiva.com.br>
> Subject: Re: suggestion: __typeof()
> Date: Wed, 18 Jan 2006 21:10:02 +0800
>
> On Wed, 2006-18-01 at 11:19 +0000, Lisa Parratt wrote:
>
> > > I'm always a fan of enforcing polite coding behaviour in the language. 
>  ;)
>
>
>
> > This is great for many uses, but totally kills the utility of the
> > function for proxy objects.
>
>
>
> > What if my userdata is a proxy for an external vector, and therefore
> > wants to present itself to Lua code as a table? With a simple __typeof
> > metamethod, it can simply return "table". With your proposed "forced
> > politeness", it's back to patching out idiot proofing before someone who
> > understands and accepts the consequences of their actions can use Lua to
> > it's full.
>
> Wouldn't a table holding your userdata do the same thing?  Return type
> "table" I mean?
>
> --
> Michael T. Richter
> Email: ttmrichter@gmail.com, mtr1966@hotpop.com
> MSN: ttmrichter@hotmail.com, mtr1966@hotmail.com; YIM:
> michael_richter_1966; AIM: YanJiahua1966; ICQ: 241960658; Jabber:
> mtr1966@jabber.cn


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