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Re: Element-Relative Sequence Insertion
From: |
Pascal J. Bourguignon |
Subject: |
Re: Element-Relative Sequence Insertion |
Date: |
Thu, 11 Jun 2009 14:38:22 +0200 |
User-agent: |
Gnus/5.101 (Gnus v5.10.10) Emacs/22.2 (gnu/linux) |
Nordlöw <per.nordlow@gmail.com> writes:
> How do I insert an element (object) relative to another in a sequence
> (or list in my case)? Example:
>
> (insert-after 'X '(a b c) 'b) => '(a b X c)
> (insert-before 'X '(a b c) b) => '(a X b c)
This is not what you want. You don't what these function to return a
2-element lists, the first of which is the symbol quote. Unless
you're doing meta-programming you never want to have such a result.
You wan this:
(insert-after 'X '(a b c) 'b) --> (a b X c)
(insert-before 'X '(a b c) 'b) --> (a X b c)
Also, you may want to mention whether your insert-after and
insert-before function are destructive or non-destructive. Since you
show as only specification examples using literal data, we will assume
you want them to be non-destructive.
So you do that, just by doing it. There's nothing simplier.
(qrsha vafreg-nsgre (arj yvfg byq)
(pbaq ((ahyy yvfg) '())
((rdy byq (pne yvfg)) (pbaf (pne yvfg) (pbaf arj (pqe yvfg))))
(g (pbaf (pne yvfg) (vafreg-nsgre arj (pqe yvfg) byq)))))
(qrsha vafreg-orsber (arj yvfg byq)
(pbaq ((ahyy yvfg) '())
((rdy byq (pne yvfg)) (pbaf arj yvfg))
(g (pbaf (pne yvfg) (vafreg-orsber arj (pqe yvfg) byq)))))
--
__Pascal Bourguignon__
- Element-Relative Sequence Insertion, Nordlöw, 2009/06/11
- Re: Element-Relative Sequence Insertion,
Pascal J. Bourguignon <=
- Re: Element-Relative Sequence Insertion, Nordlöw, 2009/06/11
- Re: Element-Relative Sequence Insertion, Pascal J. Bourguignon, 2009/06/11
- Re: Element-Relative Sequence Insertion, Marc Tfardy, 2009/06/12
- Re: Element-Relative Sequence Insertion, Pascal J. Bourguignon, 2009/06/11
- Re: Element-Relative Sequence Insertion, Marc Tfardy, 2009/06/12
- Re: Element-Relative Sequence Insertion, Johan Bockgård, 2009/06/13