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Re: How to quote a list of functions?


From: Pascal J. Bourguignon
Subject: Re: How to quote a list of functions?
Date: Fri, 14 Aug 2015 09:56:23 +0200
User-agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux)

Emanuel Berg <embe8573@student.uu.se> writes:

> "Pascal J. Bourguignon" <pjb@informatimago.com>
> writes:
>
>> Definitely not.
>>
>> The notion of type should still exist in the mind of
>> the programmer, if not in the compiler!
>>
>> The first parameter of put is of type symbol
>> (function x) returns an object of type function.
>> While it's true that in emacs lisp, symbol is
>> a subtype of function, the reverse is not true.
>> Some functions are not symbols. Therefore, the
>> Lyskoff Substitution Principle tells us that
>>
>>    (put #'upcase-region 'disabled nil)
>>
>> is a gross error. It should be:
>>
>>    (put 'upcase-region 'disabled nil)
>
> I'm not going to use this at all. I don't see the
> benefit of it because if I misspell a function, I will
> realize that immediately as the keystroke or otherwise
> invocation won't work. Besides I don't want to stop
> and think if I should but the sharp sign there or not.
> I never did and it always worked. Part of the
> pleasure with Lisp is not thinking like a computer,
> but like a man, and this poor man's typing is a step
> away from that while not offering any benefits what
> I can see. The OP presented it as something you should
> definitely do but the subsequent discussion hasn't
> showed that by far, and even he himself couldn't say
> why you should bother.

You still should, because it happens just because of an implementation
detail (that function returns a symbol, instead of a function object),
and implementation can change.

-- 
__Pascal Bourguignon__                 http://www.informatimago.com/
“The factory of the future will have only two employees, a man and a
dog. The man will be there to feed the dog. The dog will be there to
keep the man from touching the equipment.” -- Carl Bass CEO Autodesk


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