From: Andreas Politz <politza@fh-trier.de>
To: help-gnu-emacs@gnu.org
Subject: Re: How to describe something in Lisp?
Date: Tue, 03 Feb 2009 16:48:24 +0100 [thread overview]
Message-ID: <1233676167.44903@arno.fh-trier.de> (raw)
In-Reply-To: <mailman.6644.1233674526.26697.help-gnu-emacs@gnu.org>
Johan Andersson wrote:
> Hi!
>
> As a Java and Ruby programmer I sometimes find it hard to code Lisp. Right
> now I'm working on a minor mode for which the structure would obvious for me
> in Java or Ruby, but in Lisp is a riddle.
>
> I will not describe the mode itself, but give a description of the problem.
> Say I want to store a list of people in a file. And for each person, also
> some information on them in the format:
> name|age|married|sex
>
> Each time I start the mode, that file should be parsed in to some
> datastructure (which kind of is the problem). And on save, the file would be
> updated. For me it's obvious to represent a person with a class:
> class Person
> var name, age, married, sex
>
> methods...
> end
>
> Then I could easy update attributes on the objects, remove and add people
> and then update the file.
>
> I tried with a couple of solutions for this in Lisp:
>
> 1) One list named people:
> (
> (name age married sex)
> ...
> )
>
> 2) Multiple lists named name, age, married and sex where the index decides
> the connection between the lists:
> (name1 name2)
> (age1 age2)
> (married1 married2)
> (sex1 sex2)
>
> 3) Same as two, but with arrays:
> [name1 name2]
> [age1 age2]
> [married1 married2]
> [sex1 sex2]
>
>
> Each way above has their disadvantages and I think none of them is good
> enough. I read something about object orientation in lisp, but I have never
> seen this be used in Emacs. So my question is basically: What is the best
> way to model something in lisp, that you in an object oriented language
> would model with a class.
>
> Thanks!
>
(defstruct person
name
age
married
sex)
(person-name (make-person :name "Hans"))
You most likely can read about it here:
(info "(cl)Top")
Other possibilities include association lists
(info "(elisp)Association List Type")
and property lists
(info "(elisp)Property Lists")
.
-ap
next parent reply other threads:[~2009-02-03 15:48 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <mailman.6644.1233674526.26697.help-gnu-emacs@gnu.org>
2009-02-03 15:48 ` Andreas Politz [this message]
2009-02-03 16:40 ` How to describe something in Lisp? Pascal J. Bourguignon
2009-02-03 16:44 ` Johan Andersson
2009-02-03 16:54 ` Tassilo Horn
2009-02-03 17:07 ` Johan Andersson
2009-02-03 14:23 Johan Andersson
2009-02-03 16:24 ` Thierry Volpiatto
2009-02-03 16:46 ` Tassilo Horn
[not found] ` <mailman.6652.1233679633.26697.help-gnu-emacs@gnu.org>
2009-02-04 10:33 ` Pascal J. Bourguignon
2009-02-04 11:43 ` Tassilo Horn
2009-02-05 2:28 ` Pascal J. Bourguignon
2009-02-05 7:22 ` Johan Andersson
[not found] ` <mailman.16.1233818553.17492.help-gnu-emacs@gnu.org>
2009-02-06 18:53 ` Ted Zlatanov
[not found] ` <7c63jq3319.fsf@pbourguignon.informatimago.com>
[not found] ` <mailman.6723.1233747843.26697.help-gnu-emacs@gnu.org>
2009-02-04 13:26 ` Pascal J. Bourguignon
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