A case against standards

[Armin Rigo]

Hello Ilmari,

On Mon, Oct 13, 2003 at 05:00:49AM +0300, Ilmari Heikkinen wrote:
> Wouldn't it be that conversion tools have a big number of options
> because they have the ability to do several different conversions?
> Passing more input data to the converter specifies the end result more,
> which I don't see in itself as something that nullifies the ability to
> talk about converting A to B.

My previous e-mail wasn't too clear about it: actually I think that both
approaches are perfectly valid, but they are simply about different problems.
A general conversion package is most useful, and for it it makes perfect sense
to talk about conversion from point A to point B. On the other hand, in my 
approach I try to look at what occurs if we want to take *operations* as the 
starting point, and conversions as a mean to combine seamlessly operations; 
the conversions are not the end goal in my draft.

It is also a result of a personal point of view that I am always looking for
notions that we consider absolute and trying to see if they really are. I
believe that it is interesting for my approach not to consider conversions as
absolute, i.e. "convert A to B" would only have a meaning in a context. This
is because some operations do different things with the same objects, and it
doesn't always make sense to convert objects under their feet in the
"intuitive" sense. For example if you ask for the size of a file that contains
an image, you are not interested in the size that the file *could* have if the
image it contains were arbitrarily converted to another format. If the garbage
collector asks for the pointer to an object it doesn't want anything to change
under its feet; if your application asks for a pointer, garbage-collecting
around is fine. The point in my draft is that operations specify what exactly
they are interested in: "get-file-size" is interested in a "file", whereas
"show-on-screen" is only interested in the more abstract concept of "image"
and thus you can convert between file formats before show-on-screen as long as
you don't change the "image" meaning of the file.

Again this is not meant as a criticism of ccp, the focus is different.


A bientot,

Armin.