[cl-cookbook-contrib] [ cl-cookbook-Feature Requests-619966 ] Question/suggestion for hash-table page

[<no...@so...>]

Feature Requests item #619966, was opened at 2002-10-07 15:07
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=447475&aid=619966&group_id=46815

Category: None
Group: None
Status: Open
Priority: 5
Submitted By: Robert P. Goldman (rpgoldman)
Assigned to: Nobody/Anonymous (nobody)
Summary: Question/suggestion for hash-table page

Initial Comment:
I stumbled across this while looking for an answer to a
poignant hash-table question.  Namely, how does one
make a hash-table whose entries are CLOS objects?  The
spec only requires that hash-tables accept eq, eql,
equal, equalp as tests.  Unfortunately, these are all
equivalent to EQ when applied to CLOS objects.  And
none are generic functions.  An answer to this question
would sure be helpful!

If I find a good one, I'll submit it.

Cheers,
R

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Comment By: Nobody/Anonymous (nobody)
Date: 2002-10-07 23:16

Message:
Logged In: NO 

I think you might be confusing CLOS objects with the ability to use GFs, so I want to ask: do you want a 
hash-table whose equality test is a GF, or a table which distinguishes CLOS objects by some means other than 
the four equality tests you (correctly) listed?

If it's the first of these, then you're stuck. If it's the other you could write some code to extact the information you 
want out of a CLOS structure into - say - a list in such a form that equal would serve you.

Hash-tables have to be restricted in this way, otherwise they'd be too inefficient to be usable. Maybe you shouldn't 
be using a hash-table?

What are you trying to achieve? What would your equality test look like?

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You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=447475&aid=619966&group_id=46815