[r6rs-discuss] Comparison procedures' number of arguments
Ken.Dickey at whidbey.com
Thu Oct 23 19:04:01 EDT 2008
On Thursday 23 October 2008 15:42:59 Ray Dillinger wrote:
> Comparison procedures returning #f (or throwing exceptions) for
> single and zero-arity cases would cause errors in code I've written
> that sorts directories of files into order based on their timestamps.
Thank you. I do appreciate insights from people who write code to do things.
> I've assumed that the predicates are true *unless* there is a pair
> in sequence that violates the condition, because that seems to me
> the obvious and only reasonable way for them to be defined.
Assuming a condition is true without requiring existence is something one
should do very carefully. It would seem much more natural to prove
properties of entities that exist than for those that don't exist.
1st Gangster: "If the guy is dead, you can't prove he is unhappy."
2nd Gangster: "I think we just proved that he can't be unhappy."
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