From: "Óscar Fuentes" <ofv@wanadoo.es>
To: help-gnu-emacs@gnu.org
Subject: Re: safe way to add contents to a file ?
Date: Wed, 18 Dec 2019 01:36:49 +0100 [thread overview]
Message-ID: <87k16ua2qm.fsf@telefonica.net> (raw)
In-Reply-To: 0FE61EAF-672C-4348-8107-F4C3D176FCF4@traduction-libre.org
Jean-Christophe Helary <jean.christophe.helary@traduction-libre.org>
writes:
> I'm struggling with what is the ideal "elispy" way of adding contents
> to a file at a given position.
>
> What I want it:
> - create some content
> - put that content at a specific location in a file saved on disk
> (current use case: add an xml block to an RSS file)
>
> I thought write-region would do the trick but there are 2 issues with
> it
>
> 1) if APPEND is a number, that's the position from which my contents
> will *overwrite* the rest of the file (I want to *insert* my contents)
>
> 2) there are weird things like the whole code where I call this
> function is actually copied to the target file buffer and I have no
> idea how to prevent that.
>
> So, I thought of something a bit convoluted:
>
> use a temporary buffer
> insert the contents of the file there
find-file-noselect takes care of creating the buffer and reading the
contents of the file. Later you must get rid of the buffer.
> find the point where I want to insert my contents
use `insert' or `insert-buffer-substring'
> write all that to the original file
>
> But I thought, it's not like such things don't happen all the time in
> emacs, so there must be a better workflow.
>
> But the reference is incredibly cryptic regarding that and the Intro
> does not address any file i/o at all...
The sequence of operations above is actually quite simple (although not
very efficient if the target file is large and your new content is near
the end).
next prev parent reply other threads:[~2019-12-18 0:36 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-18 0:03 safe way to add contents to a file ? Jean-Christophe Helary
2019-12-18 0:36 ` Óscar Fuentes [this message]
2019-12-18 3:20 ` Jean-Christophe Helary
2019-12-20 13:50 ` Jean-Christophe Helary
2019-12-20 16:00 ` Stefan Monnier
2019-12-22 3:14 ` Jean-Christophe Helary
2019-12-22 4:42 ` Jean-Christophe Helary
2019-12-22 14:37 ` Óscar Fuentes
2019-12-22 22:18 ` Jean-Christophe Helary
2019-12-23 0:08 ` Óscar Fuentes
2019-12-22 18:23 ` Stefan Monnier
2019-12-18 3:59 ` Stefan Monnier
2019-12-18 9:41 ` Jean-Christophe Helary
2019-12-18 13:10 ` Óscar Fuentes
2019-12-18 22:33 ` Jean-Christophe Helary
2019-12-18 14:10 ` Stefan Monnier
2019-12-18 22:25 ` Jean-Christophe Helary
2019-12-18 22:27 ` Jean-Christophe Helary
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