On Sun, Sep 26, 2010 at 13:44, Nilson <
nilson.brazil@gmail.com> wrote:
> Hi guys,
>
> Could you send me opinions about OOBIT patch? I would appreciate any opinion
> that could help me to decide the patch's future.
>
> Status Report:
> ***********
> OOBIT on tt field of values
> status: done
> runtime cost: 1 additional AND on type read and 1 XOR, 1 AND and 1 OR on
> type write.
>
> ***********
> OOBIT ooset and ooget functions
> status: done
>
> ***********
> Language extension to indicate REQUIRES SELF
> status: done
> how: adding METHOD keyword (could be done without a new keyword)
>
> Example:
>
> a ={}
>
a.name = 'Lua'
> a.print = method() print('Name: ',
a.name) end -- solves a:f=function()...
> a:print() -- still uses colons
>
>>> Name: Lua
>
> ***********
> Set the OOBIT.of a function when it REQUIRES SELF
> status: on queue (next thing to do)
>
> ***********
> THE MAIN GOAL: Using just the dot syntax, automatically add a self parameter
> when a function requires it.
> status - planning, prototyping
>
> ESTIMATED COST (current approach) :
>
> * 1 additional VM operation OP_AUTOSELF: it is an OP_SELF generated
> automatically (without colon)
>
> * 1 extra stack parameter on every table call without colon,
> <path-to-table>.field() (see 1)
>
> * 4 to 16 additional fast/machine level operations to decide how to handle
> each CALL
>
> * 4 to 10 additional fast/simple machine level operations to cleanup after
> the call
>
> * a couple of additional integer fields
>
>
> 1 - I could not find a way to preserve the table without use of the stack. I
> think it´s not possible, but I will try a little more.
> IMHO, this is the more expensive cost.
>
> ***********
> PROS
>
> * A safe way to eliminate the colon usage in function calls.
>
> * "REQUIRES SELF" enhances the function´s semantics what helps to detect
> "missing self" errors.
>
> * If OOBIT is allowed to be set in other values - like tables - it could
> help to enhance the whole Lua´s OO experience.
>
>
> CONS
>
> * The extra runtime cost will be (a little bit) higher, whether the
> programmer use only dots in table calls or not.
>
> * To some platforms and/or applications, the extra runtime cost could be too
> expensive.
>
> * I don´t know the impact on LUA JIT.
>
> ***********
> Well, in your opinion, it´s worth?
>
> You can send your answer directly to my email, if the mailing list's rules
> allow (I´m new here).
>
>
> Thanks.
>
> --
> Nilson
>
>
>
a.print = method() print('Name: ',
a.name)
