Re: encapsulating directory operations

Kaz Kylheku <643-408-1753@kylheku.com> writes:

On 2025-05-20, Keith Thompson <Keith.S.Thompson+u@gmail.com> wrote:

"Paul Edwards" <mutazilah@gmail.com> writes:

[...]

As far as I know, there was never any LOGICAL barrier
to including basic directory manipulation in C90.

>
None that I can think of.

>
There was a significant barrier. The ANSI group which standardized
C was mainly looking at surveying and codifying existing practice.

Agreed.  I consider that a practical barrier, not a "LOGICAL" one.

The ANSI C committee *could* have added directory operations to the C
standard library.  (I'm not suggesting that they should have.)

[...]

Sure, it would be theoretically possible to treat directories as files,
and to make reading from a FILE* resulting from calling fopen() with a
directory name give you access to the directory entries.

>
I implemented something like this. It is fine; I don't regret it.
>
i1> (open-directory ".")
#<dir-stream b7b90820>
2> (get-line *1)
"htrailer.txr"
3> (get-line *1)
"y.output.bison"
4> (get-line *1)
"jmp.S"
5> (open-file "/etc/hosts")
#<file-stream /etc/hosts b7b7a8b0>
6> (get-line *5)
"127.0.0.1\tlocalhost"
7> (get-line *5)
"127.0.1.1\tsun-go"

It looks like it treats a directory as a file containing a
sequence of *lines*, each of which is a file name.  The problem
with that is that on some systems, file names can legally include
newline characters.  I don't suggest it's not a horrible idea to
take advantage of that, but it is something that would have to be
addressed in a language standard.

[...]

--
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
void Void(void) { Void(); } /* The recursive call of the void */