Re: What's up with token filters (Re: New operators?)

["Olivier Delannoy" <olivier.delannoy@...>]

On 4/13/07, Olivier Galibert <galibert@pobox.com> wrote:
> On Fri, Apr 13, 2007 at 03:27:17PM +0200, Olivier Delannoy wrote:
> > Lua should not evolve in a way that makes the language more complex
> > and not clear for the sake of not writing a few more extra characters.
> > Lua is small and should stay small. 1 more vote against += -= *= /= --
> > ++ and all other operator added to the language for programmer
> > lazyness. If one want all this operation its another language and it
> > can go with one providing this kind of facility.
>
> Oh please.  Read the thread you're replying to, if += and ++ were
> *only* syntaxic sugar it wouldn't be a problem to add them.  It's
> because they imply way more than that that there are issues.
In what i++ is different from i = i + 1 (I assume post increment here.)


> For those who stumble on this post, some of the real reasons are:
> - in lua assignation is a statement, not an expression, and people who
>   want ++/-- want to use it as an expression.  Assignation-as-expression
>   carries a lot of complexity for the programmer/maintainer a
>   non-professional-programmer language lika lua would rather avoid.
>
> - lua's multi-assignation does not interact very well with += and friends
>
> - all these operators have in-place modification and atomicity semantics
>   that do not go very well with lua either.  ':' is already more complex
>   in that area than one would think at first glance.

Could you details the in-place modification in the context of the lua
stack and state please ?

Atomicity as no meaning in lua. Lua is not multi threaded and there is
only one execution thread per state active at a time. so a whool chunk
can fairly well be considered atomic.

Why : is more complex than it appears ?
a.truc(a, something) is strictly equivalent to a:truc(something)



> As usual, power and complexity go hand in hand, and in that case the
> complexity rise is too high.
>
>   OG.


--
Olivier Delannoy
ATER
PRiSM Laboratory
Versailles University, FRANCE