Re: Enhanced tostring

[Edgar Toernig <froese@...>]

Luiz Henrique de Figueiredo wrote:
>
> > Could someone remind me why Lua stringifies an object o by way of
> > getmetatable(o).__tostring(o) rather than o:__tostring()?
> 
> In my libraries and probably many others, the two expressions are equivalent.

Yeah, but should they?  At the moment "o" is a table and you add
arbitrary elements to it everything falls apart.  Just look at the
recent thread "Tracking number of pairs in a dictionary" [1].
One suggestion was:

    function make_LimitedTable(limit)
        [...]
        return setmetatable({}, <metatable with add, del, etc>)
    end
    > t = make_LimitedTable(2)
    > t:add('a',{})
    > t:add('b',{})

Guess what happens on

    t:add('add',{})

And this was not the first time I saw this broken usage.

IMO it's time to drop the "colon is only syntactic sugar" dogma.

Ciao, ET.


[1] http://lua-users.org/lists/lua-l/2009-10/msg00007.html