Re: __iter metamethod?

[Ben <thebassplayer@...>]

Have you looked at http://lua-users.org/wiki/GeneralizedPairsAndIpairs ?

On 10/9/07, steve donovan <steve.j.donovan@gmail.com> wrote:
> Hi guys,
>
> Has anybody given some thought to the usefulness of an __iter
> metamethod? It would specifically be called by a for-statement if it
> was not given an explicit iterator function. For example,
> t = {10,20,30}
> setmetatable(t,{
>    __iter = ipairs
> }
> for i,v in t do
>   print(i,v)
> end
>
> Which is precisely the old Lua 5.0 behaviour ;)
>
> But this can be generalized; file objects could have an __iter
> metamethod, and then one can iterate over all input lines in a
> Pythonesque way:
>
> for line in io.stdin do
> ...
> end
>
> The motivation is to make the concept of _sequence_ more useful in Lua...
>
> steve d.
>