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Re: Hash table read syntax in guile 2.0

From: Hengqing Hu
Subject: Re: Hash table read syntax in guile 2.0
Date: Mon, 18 Feb 2013 11:14:45 +0800

Though I didn't look into the implementation.

I suppose length is a constant time operation here,
if you use fold instead to get the same thing.
It would be linear time.

Knowing something is empty or not rises after I put something inside
and then take something out.
Then I dont't know whether there are still something left, so I need to examine 
Or if something can tell me.

All is about to be able to have constant time access to specific information in
this hash table implementation.

在 2013-2-18,10:47,Daniel Hartwig <address@hidden> 写道:

> On 18 February 2013 10:36, Hengqing Hu <address@hidden> wrote:
>> Thanks for the collaboration.
>> You are right, that's what I mean by a deep list.
> So what do you consider the length of the example deep list, is it
> two, three, or six?  Length implies a particular dimension, which is
> naturally the ordering of the outer list.
> Scheme considers:
> (length '((1 2 3) (4 5 6)))
> =>
> 2
> ?
>> One usage of knowing the information is to tell
>> whether the hash table is empty or not,
>> Since a hash-empty? procedure is not provided.
> Yes but, why do you want to know that?  Isnt what matters whether a
> particular key exists or not, and what is its value?  This is the
> primary purpose of hash tables, no?
> The number of active bindings in the hash table is really just a book
> keeping detail.

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