Re: Re: [babel] How to kill two birds with one stone?

[Nick Dokos <nicholas.dokos@hp.com>]

Sébastien Vauban <wxhgmqzgwmuf@spammotel.com> wrote:

> ... 
> * List all files in dir (version of Seb)
> 
> My code was a bit more complex... because I need to be able to correctly take
> care of filenames containing spaces inside them (I'm on Windows, I never do
> such a thing, but there are well spaces on the files I wanna graph).
> 
> #+srcname: graph-files-seb
> #+begin_src sh :results vector :var dir=graph-dir
>   find $dir -type f -print |\
>   while read -r name
>   do
>       echo "\"${name##*/}\""
>   done
> #+end_src
> 
> #+results: graph-files-seb
> | dan   |         |
> | eric  |         |
> | other |         |
> | "seb  | vauban" |
> 

I suspect that this is a losing battle: spaces in filenames are legal,
they are common on Windows systems, but they are a PITA. The main reason
is that a *lot* of tools (particularly Unix tools of a certain age)
assume that spaces in filenames will not occur and break in mysterious
and unexpected ways when presented with a directory structure that
contains such.

There are various workarounds (the most important of which, practically speaking,
is the idiom

   find ... -print0 | xargs -0 ....

which causes ``find'' to use a null byte as a separator and ``xargs'' to
search for same in order to split the list into its constituent
components - null bytes being illegal in filenames), and there is a
long, fairly exhaustive discusssion of such matters in David Wheeler's
enlightening essay:

   http://www.dwheeler.com/essays/fixing-unix-linux-filenames.html

but none of these would help in this case, because the culprit here
turns out to be org-table-convert-region:

,----
| org-table-convert-region is an interactive Lisp function in
| `org-table.el'.
| 
| (org-table-convert-region BEG0 END0 &optional SEPARATOR)
| 
| Convert region to a table.
| The region goes from BEG0 to END0, but these borders will be moved
| slightly, to make sure a beginning of line in the first line is included.
| 
| SEPARATOR specifies the field separator in the lines.  It can have the
| following values:
| 
| '(4)     Use the comma as a field separator
| '(16)    Use a TAB as field separator
| integer  When a number, use that many spaces as field separator
| nil      When nil, the command tries to be smart and figure out the
|          separator in the following way:
|          - when each line contains a TAB, assume TAB-separated material
|          - when each line contains a comma, assume CSV material
|          - else, assume one or more SPACE characters as separator.
| 
`----

It is called with a nil separator so it uses its "smart" mode and counts
one or more whitespace characters as the separator (I wonder
what would happen with a filename that contains a comma :-)

In any case, the region has the filenames one per line, so if
org-table-convert-region could parse a newline-separated list (and if
there was a way to specify the newline separator from higher levels)
everything would be hunky dory; there might be a way to specify the
separator using dynamic scoping, but org-table-convert-region would
require some changes to take advantage of it.

Nick