Re: bug#47885: [PATCH] org-table-import: Make it more smarter for interactive use

[Maxim Nikulin]

On 11/05/2021 01:36, Utkarsh Singh wrote:
> What do we mean by interactive preview?  Does this mean that we should
> present a user with a list of possible delimiters using minibuffer?

I mean something like the dialog that LibreOffice shows on opening of a 
csv file. There are various options and table preview that allows to 
check if options are selected correctly before dropping to usual 
spreadsheet interface. I have no idea what is the best way to implement 
something like this in emacs. Likely it is out of scope of the discussed 
patch. I do not know what is your use cases. My intention was to show 
that CSV import could be quite cumbersome.

Some users believe that CSV is a reliable portable format and expect 
support of most features from Excel. Actually there are plenty of 
dialects and no way to determine which one was used (e.g. no header that 
defines field or string separator).

> For ex (please review my usage of alist):
>
> #+begin_src elisp
> (defvar my-separator-alist '(("comma" . ",")
>                              ("tab" . "\t")
>                              ("semicolon" . ";")
>                              ("colon" . ":")
>                              ("space" . " ")))
>
> (defun my/table-import (file separator)
>    (interactive (list (read-file-name "Import CSV file: " nil nil t)
>                      (cdr (assoc (completing-read "Separator: " 
> my-separator-alist)
>                                  my-separator-alist))))
>    (org-table-import file separator))
> #+end_src

With such function it is necessary to open file at first to see what 
separator is used inside.

My comments were related to the "guess" part of your patch. Comma is 
tried first. Consider the following file

A;1,2;3,4;5,6
B;7,8;9,1;11,12
C;13,14;15,16;17,18

Decimal separator is ",". Field separator is ";" but there are plenty of 
"," in each row.

LANG=fr_FR.UTF-8 python3 -c "import locale as l; l.setlocale(l.LC_ALL, 
''); print(l.format_string('%.2f', 123456.789))"
123456,79

Comma is decimal separator for es_ES, de_DE, ru_RU, etc. The point is 
that order in which separator candidates are tried should depend on 
active locale.

I do not insist that interactive preview or smarter approach to guess 
separator have to be implemented. Feel free to disregard my comments. I 
am just not sure whether you are aware of limitations for noticeable 
part of users.