Re: __newindex rawsetless semantics?

["Thiago L." <fakedme@...>]

On 14/10/14 11:08 AM, Javier Guerra Giraldez wrote:
> On Tue, Oct 14, 2014 at 8:22 AM, Thiago L. <fakedme@gmail.com> wrote:
> > On 14/10/14 10:18 AM, Javier Guerra Giraldez wrote:
> > > On Tue, Oct 14, 2014 at 8:06 AM, Thiago L. <fakedme@gmail.com> wrote:
> > > > the gain is that I don't have to expose rawset...
> > > but what if i don't want to set anything to this table?
> > then you don't return anything? (or return nil key?)
> or set more than one value? or to a different table?  in the end you
> need the equivalent of rawset()

function __newindex(t,k,v)
    if k == "special key" then
        for i,val in ipairs(split(k,"\n")) do
            t[whatever + i] = val
        end
    else
        return k,v
    end
end

With my proposal the above piece of code would work just like this one 
with current Lua:

function __newindex(t,k,v)
    if k == "special key" then
        for i,val in ipairs(split(k,"\n")) do
            t[whatever + i] = val
        end
    else
        rawset(t,k,v)
    end
end

If you *need* rawset, then... well don't use this sandbox :P There are 
ways to work around lack of rawset:

local skip = false

function mt1.__newindex(t,k,v)
    if k == "special" then
        skip = true
        t2[v[1]] = t2[v[2]]
    else
        return k,v
    end
end

function mt2.__newindex(t,k,v)
    if skip then
        return k,v
    else
        error("Attempt to write to t2")
    end
end

-- etc

It also avoids a function call, if that matters...

So no, in the end you do NOT need the equivalent of rawset. Plus, the 
proposal was never about removing rawset anyway...
> unfortunately, it seems that this is a case of "all is well, don't
> change anything".
>
> Just guessing: this stems from the idea that __newindex is used mostly
> to ultimately set a single value to the same table, and makes it the
> default.  but if you remove the previous way to do it (rawset), you
> have to provide all the capabilities.  in many cases by some contrived
> and non-obvious constructions.
>
> why not to expose rawset()?  is it for security reasons?  it might be
> easier to provide a slightly patched version that only skips user's
> __newindex but still respects those defined by your environment.