Re: [Texmacs-dev] Scheme to Prolog

[Henri Lesourd]

Joris van der Hoeven wrote:

> 1) I don't think that functions like buffer-tree are "redudant":
> this is the *clean* way to get the current buffer tree.
>  
Providing a clean API wich only provides means for getting
the *current* buffer tree is good, and perhaps it is clean, but
unfortunately it is also *incomplete* : very naturally, one is
also lead to think about getting info about the other buffers.

In this respect, using "(path->tree '())" for getting the current
buffer root tree is perhaps less clean, but on the other hand
it is complete, in the above sense. And as soon as something
is complete, all the other things that implement only a part
of this something in a different way (even if it is done in a
cleaner way) appear to be redundant.

To avoid such problems, one should take care about
providing clean and reasonably *complete* APIs in the
first place.


> 2) It is good style *not* to work with paths when not necessary.
I agree with this. Working with objects thru pointer manipulation
is the clean, and very classical way to implement a library for
managing datastructures. Too bad it has not been done in the
first place. Now we are stuck with these things with paths which
are more confusing than anything else, althrough useful in some
cases (like the example you gave).


> Indeed, trees in the document *know* about their position
I didn't said it explicitely because it is a very usual property
of objects. I could say as well that in C, objects *know*
their address, and that you can fetch this address by means
of the operator "&". But such an explanation appears to be
redundant, provided you are sure that people know the very
basics of memory allocation in a computer.


Best, Henri