[XML-SIG] RE: Equality tests on DOM nodes
John Cowan
cowan@locke.ccil.org
Mon, 14 Dec 1998 16:56:38 -0500
Fred L. Drake wrote:
> Typically,
> two Python objects (let's take lists as an examples) are considered
> equal if their contents are the same; equality of two objects is not
> considered to be an unchangable characteristic.
The trouble with that scheme is that it makes equality hard to
reason about. Intuitively, we expect equality to be transitive,
(if a = b and b = c then a = c), reflexive (a = a), and symmetrical
(if a = b then b = a). Making equality depend on mutable properties
defeats this: a might = b at one time, but a later check for
b = a might fail.
> a.reverse()
I presume this is a *destructive* reverse (leaves a reversed)?
--
John Cowan http://www.ccil.org/~cowan cowan@ccil.org
You tollerday donsk? N. You tolkatiff scowegian? Nn.
You spigotty anglease? Nnn. You phonio saxo? Nnnn.
Clear all so! 'Tis a Jute.... (Finnegans Wake 16.5)