Re: [PATCH] Postinstall script ordering in setup - take 3

[Robert Collins <rbcollins at cygwin dot com>]

On Mon, 2003-03-17 at 07:13, Igor Pechtchanski wrote:

> > And for clarity: my suggested tweak is also not sufficient to provide a
> > weak ordering.
> > Rob
> 
> Rob,
> 
> Your suggested tweak provides a total ordering.  The "unordered(x,y)"
> [!(x < y) && !(y < x)] relation is false for any x != y [since either
> (x < y) or (y < x) always holds].  So all equivalence classes have one
> element: "unordered(x,x)" is always true.  You get transitivity trivially,
> as "unordered(x,y) && unordered(y,z)" is only true if x == y == z, and
> then you also have "unordered(x,z)".
> 	Igor

It doesn't. It fails because it doesn't obey the requirements for an
equivalence class. The ordering it provides is 100% dependent on the
order of the comparisons. Thats fine when two elements are in the same
equivalence class, but this will shuffle elements outside such classes.

Rob

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