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Re: Creating a list
From: |
David Kastrup |
Subject: |
Re: Creating a list |
Date: |
Thu, 19 Nov 2009 14:57:17 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/23.1.50 (gnu/linux) |
Cecil Westerhof <Cecil@decebal.nl> writes:
> David Kastrup <dak@gnu.org> writes:
>
>>>>> At the moment I create a list with:
>>>>> (setq ret-val (cons total-amount (cons current-amount ())))
>>>>> I thought about doing it with:
>>>>> (setq ret-val (cons total-amount '(current-amount)))
>>>>>
>>>>> But then the second value is the string current-amount
>>>>
>>>> Wrong. The _symbol_ current-amount.
>>>
>>> When evaluating I got:
>>> (1570378.2570192777 current-amount)
>>> That is why I thought I got the string.
>>
>> A string would have quote marks around it.
>
> Off course.
>
> But I have a few questions on my mind.
> - Why is the first shown as value and the second as _symbol_?
Because you quoted the entire list containing the second value.
> - current-amount is a local variable. How is it possible that the symbol
> is still defined?
I really recommend that you read a Lisp introduction. Your questions
are very very basic.
A symbol, like a plain unquoted list, _is_ a valid expression all by
itself. In the context of evaluation, a further interpretation tries
going from there (fetching a symbol's value, calling the first element
of a list as a function on the rest). But whether or not you can
usefully call eval on it, either are printable and useful expressions.
--
David Kastrup
- Creating a list, Cecil Westerhof, 2009/11/19
- Re: Creating a list, David Kastrup, 2009/11/19
- Re: Creating a list, Cecil Westerhof, 2009/11/19
- Re: Creating a list, David Kastrup, 2009/11/19
- Re: Creating a list, Cecil Westerhof, 2009/11/19
- Re: Creating a list, Barry Margolin, 2009/11/19
- Re: Creating a list, Cecil Westerhof, 2009/11/19
- Re: Creating a list, Pascal J. Bourguignon, 2009/11/19
- Re: Creating a list,
David Kastrup <=
- Re: Creating a list, Cecil Westerhof, 2009/11/19
- Re: Creating a list, Pascal J. Bourguignon, 2009/11/19
Gnus: Some new mails are automatically marked as 'O', Wang Lei, 2009/11/19