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Re: Null filename ("") is considered to correspond to an existing, read
From: |
Eli Zaretskii |
Subject: |
Re: Null filename ("") is considered to correspond to an existing, readable, and writable file? |
Date: |
Tue, 03 Jan 2006 07:32:24 +0200 |
> From: "Drew Adams" <address@hidden>
> Date: Mon, 2 Jan 2006 19:27:56 -0800
>
> Besides, where is the section of the manual that says that, unless stated
> otherwise, all file-name arguments to functions are relative
This is a basic notion of every filesystem: every file is relative to
the current directory, unless it begins with the root directory
string. I don't thing the Emacs manual should teach such basics.
> and they are all relative to the `default-directory'?
In Emacs, `default-directory' is the variable that stores the current
directory that is in effect when you are in that file's buffer. The
Emacs manual says in the node "File Names":
Each buffer has a default directory which is normally the same as the
directory of the file visited in that buffer. When you enter a file
name without a directory, the default directory is used. If you specify
a directory in a relative fashion, with a name that does not start with
a slash, it is interpreted with respect to the default directory. The
default directory is kept in the variable `default-directory', which
has a separate value in every buffer.
Clear enough?
> Beyond the doc, wouldn't you expect functions with these names to return nil
> for a "" argument? What's the purpose of not checking this case, correctly
> applying the meaning of the function's name and returning nil?
>
> Is it so that you can use (file-exists-p "") to test the existence of
> directory `default-directory'? What's the advantage of such a "feature"?
> There are other, more readable ways to test that: (file-exists-p
> default-directory), for instance.
>
> Sorry, I still don't get it. Why is the design like this?
This was discussed here some months ago, although I couldn't find that
thread in the few minutes I had to look for it.
- Null filename ("") is considered to correspond to an existing, readable, and writable file?, Drew Adams, 2006/01/02
- Re: Null filename ("") is considered to correspond to an existing, readable, and writable file?, Luc Teirlinck, 2006/01/02
- RE: Null filename ("") is considered to correspond to an existing, readable, and writable file?, Drew Adams, 2006/01/02
- Re: Null filename ("") is considered to correspond to an existing, readable, and writable file?, Luc Teirlinck, 2006/01/02
- RE: Null filename ("") is considered to correspond to an existing, readable, and writable file?, Drew Adams, 2006/01/03
- Re: Null filename ("") is considered to correspond to an existing, readable, and writable file?, Eli Zaretskii, 2006/01/03
- Re: Null filename ("") is considered to correspond to an existing, readable, and writable file?, Luc Teirlinck, 2006/01/03
- Re: Null filename ("") is considered to correspond to an existing, readable, and writable file?,
Eli Zaretskii <=
- RE: Null filename ("") is considered to correspond to an existing, readable, and writable file?, Drew Adams, 2006/01/03
- Re: Null filename ("") is considered to correspond to an existing, readable, and writable file?, Stefan Monnier, 2006/01/03
- RE: Null filename ("") is considered to correspond to an existing, readable, and writable file?, Drew Adams, 2006/01/03
- Re: Null filename ("") is considered to correspond to an existing, readable, and writable file?, Eli Zaretskii, 2006/01/03
- RE: Null filename ("") is considered to correspond to an existing, readable, and writable file?, Drew Adams, 2006/01/03
- Re: Null filename ("") is considered to correspond to an existing, readable, and writable file?, Luc Teirlinck, 2006/01/03
- Re: Null filename ("") is considered to correspond to an existing, readable, and writable file?, Luc Teirlinck, 2006/01/03
- RE: Null filename ("") is considered to correspond to an existing, readable, and writable file?, Drew Adams, 2006/01/03
- Re: Null filename ("") is considered to correspond to an existing, readable, and writable file?, Thien-Thi Nguyen, 2006/01/07
- Re: Null filename ("") is considered to correspond to an existing, readable, and writable file?, Eli Zaretskii, 2006/01/03