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Re: Making 'eq' == 'eql' in bignum branch
From: |
John Yates |
Subject: |
Re: Making 'eq' == 'eql' in bignum branch |
Date: |
Fri, 10 Aug 2018 12:52:53 -0400 |
On Fri, Aug 10, 2018 at 11:44 AM Pip Cet <address@hidden> wrote:
> giving up IEEE compliance and surprising the occasional user who wants it.
I have not been paying much attention to this thread so perhaps I am
preaching to the choir here...
In my day job one of my multi-year efforts has been to bring Mathwork's
MATLAB optimization and generated code into ever greater compliance
with the IEEE 754 standard. As such I have much exposure to both the
specifics of the standard and the (often erroneous) expectations of users.
The standard talks about values, not objects, and relationships between
values. NaN is a value just as much as 2 or pi.
More importantly the standard says that two NaN values (even if fetched
from the same container within a single expression) _always_ compare
not equal.
Were I that "occasional user who wants" IEEE compliance in my elisp
code I would expect comparisons of NaNs (whether via either eq or eql)
to return nil. My sense is that to achieve that effect one must _always_
compare floating point objects, even if they reside at the same address.
/john
- Re: Making 'eq' == 'eql' in bignum branch, Eli Zaretskii, 2018/08/01
- Re: Making 'eq' == 'eql' in bignum branch, Paul Eggert, 2018/08/01
- Re: Making 'eq' == 'eql' in bignum branch, Eli Zaretskii, 2018/08/01
- Re: Making 'eq' == 'eql' in bignum branch, Paul Eggert, 2018/08/03
- Re: Making 'eq' == 'eql' in bignum branch, Eli Zaretskii, 2018/08/03
- Re: Making 'eq' == 'eql' in bignum branch, Pip Cet, 2018/08/10
- Re: Making 'eq' == 'eql' in bignum branch, Stefan Monnier, 2018/08/10
- Re: Making 'eq' == 'eql' in bignum branch, Pip Cet, 2018/08/10
- Re: Making 'eq' == 'eql' in bignum branch, Stefan Monnier, 2018/08/10
- Re: Making 'eq' == 'eql' in bignum branch,
John Yates <=
- Re: Making 'eq' == 'eql' in bignum branch, Eli Zaretskii, 2018/08/10
- Re: Making 'eq' == 'eql' in bignum branch, Paul Eggert, 2018/08/10