On Sat, Mar 08, 2014 at 10:43:46PM +0100, Nathann Cohen wrote:
> Tricks like this one makes it hard for people to work with category
> code, and in particular to learn how it works by looking at the code.
> Somebody said previously on this thread that "if somebody is playing
> with categories, then he must have read the manual first" and I
> believe that this is already wrong. Sometimes, you (= I ) have to deal
> with category code, even though you do not know what it is, just
> because you encounter a bug or because some part of the code forces
> you to do something with categories (facades in Posets, for instance
> ?). That's why you have standards like that, to make sure that
> everybody can coexist and work together.
Yup. But on the other hand making everything completely explicit as in
a plain hierarchy of abstract classes would require much
duplication. Actually a potentially exponential growth of
duplication. That would not make the code any easier to read. So it's
all about finding the right balance. All I am saying is that, thanks
from the strong semantic provided by math, the right balance is
shifted a bit compared to more mainstream code.
> To me it's a bit like for global variables. It's correct code, it
> compiles, but it is hard to guess the source of the problem when you
> are fighting with a bug. Even if it is documented somewhere, as you
> have no idea what you are looking for exactly. Making the link
> explicit is exactly the hint you need to tell you where you should go
> in order to understand what happens.
One difference being that each global variable needs to be documented,
whereas here it's a one time shot to learn the meaning of the syntax.
Cheers,
Nicolas
--
Nicolas M. Thiéry "Isil" <nthi...@users.sf.net>
http://Nicolas.Thiery.name/
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