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Re: Structured data in Emacs Lisp
From: |
Klaus Berndl |
Subject: |
Re: Structured data in Emacs Lisp |
Date: |
27 Apr 2005 17:27:16 +0200 |
User-agent: |
Gnus/5.09 (Gnus v5.9.0) Emacs/21.3 |
If you want to move around datas which belong together i recommend `defstruct'
which is in both Emacs and XEmacs available! It is a macro of the cl-package
so you can use it safely also with GNU Emacs ;-)
See the info-manual of `defstruct' - It#s in the cl-info-manual!
defstruct allows you to get and set slots via key-names so there are position
independed!
Does this help?
Klaus
On Tue, 26 Apr 2005, mailshield.gg@mailnull.com wrote:
> I'm writing a moderately complex Emacs package and not being a Lisp
> guru I wonder what is the best way to handle data structures in
> Elisp. The emphasis is not on efficiency, rather on readability.
>
> For example, from a function I want to return three values. How should
> I do this?
>
> Using a list? (Value1 Value2 Value3)?
>
> This has the disadvantage of storing specific values on specific
> positions, so the caller must now the first element of the list is
> Value1, etc. And what if the return value is changed later and Value2
> is not returned anymore? Then I have to fix every invocation of the
> function.
>
> Or maybe an association list? '((value1 . 3) (value2 . 4) (value3 . 5))
> It's certainly more resistant to code changes, but feels a bit
> heavyweight. (Maybe its just me.)
>
> Or is there an other Lispish way to handle structured data I don't
> know about?
--
Klaus Berndl mailto: klaus.berndl@sdm.de
sd&m AG http://www.sdm.de
software design & management
Carl-Wery-Str. 42, 81739 Muenchen, Germany
Tel +49 89 63812-392, Fax -220