On Jan 20, 2008 8:20 AM, Martin Albrecht <[EMAIL PROTECTED]> wrote:
>
> Hi there,
>
> I've submitted the patch
>
> http://trac.sagemath.org/sage_trac/ticket/1816
>
> to trac and Nick refereed it. The patch implements that if a multivariate
> polynomial ring is 'print'ed the output is quite verbose and structured. This
> behavior was in repr_long() before.
>
> EXAMPLE:
>
> {{{
> sage: P.<x,y,z> =
> PolynomialRing(QQ,order=TermOrder('degrevlex',1)+TermOrder('lex',2))
> sage: print P
> Multivariate Polynomial Ring
> Base Ring : Rational Field
> Size : 3 Variables
> Block 0 : Ordering : degrevlex
> Names : x
> Block 1 : Ordering : lex
> Names : y, z
> }}}
>
> Nick writes: "That's *not* okay -- way too much by default" but I disagree.
> The motivation for adding more (structured) information to the long
> representation came from the similar behavior of symbolic expressions:
>
> EXAMPLE:
>
> {{{
> sage: f = x/var('y')
> sage: f
> x/y
> sage: str(f)
> '
> x\r\n -\r\n
> y'
> sage: print f
> x
> -
> y
> }}}
>
> Thus I figured it would be okay to have long representations returned by
> __str__.
>
> The question now is, how others think about it.
+1
I like your patch. But I would also very much like to hear what others think.
Also, if one makes a free module M (say) over a multivariate polynomial ring R,
I think the __repr__ method on M will do "... %s ..."%R, which will
call R.__str__(),
which will result in completely unreadable output. So we have to change a lot
of __repr__ methods to use %r instead of %s. That's not necessarily bad; we
had to do that with symbolic already.
I can tell you also having been at a big IMA workshop on computational
commutative
algebra, that _users_ of commutative algebra software really do
greatly appreciate
things like:
* clear verbose output
* ASCII art / typesetting and anything else that makes staring at
equations or formulas easier
* automatic variable name injection (inject_on()).
They seem to care much more about that sort of thing that say a typical
number theorist or maybe crypto person.
Your patch goes along with this theme well.
-- William
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