how the $@%& do you add a property to a plist?

how the $@%& do you add a property to a plist?

[Matt Price]

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Hi,

I am continuing to work on my marking stuff; it's working really well,
actually.

I am currently importing a list of student names and emails from a csv file
-- this is normally how I get the list of enrolled students.  I have
modified the defauly settings from our Universities CSV export so I get
these files in the form:

Student Name,Email
Student One, em.address@utoronto.ca
Student Two, em.address2@utoronto.ca

I then parse this into a list, each element of which is itself a list
("Student One" "em.address@utoronto.ca"), etc.

This is OK, but not very robust. I would like instead to set *properties*,
in case the CSV file has some other ordering of fields.  So I've tried this:

(defun parse-plist-csv-file (file)
  (interactive
   (list (read-file-name "CSV file: ")))
  (let ((buf (find-file-noselect file))
        (result nil))
    (with-current-buffer buf
      (goto-char (point-min))
      (let ((header (split-string  (buffer-substring-no-properties
                                    (line-beginning-position)
(line-end-position)) ","))
            )
        (while (not (eobp))
          (let ((line  (split-string (buffer-substring-no-properties
                                      (line-beginning-position)
(line-end-position))))
                (count 0)
                (new-plist '()))
            (while (< count (length line))
              (setq plist-new (plist-put new-plist  '(nth count header)
(nth count line)))
              (setq count (1+ count)))
            (push  new-plist result)
            (forward-line 1))))
      (reverse result))))

The line that's not working here is:

              (setq plist-new (plist-put new-plist  '(nth count header)
(nth count line)))

which just inserts nil nil into 'new-plist. Obviously I'm making some
elementary elsip mistake, but my elisp is too weak to figure it out.  Can
you guys help?  thanks,
Matt

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Re: how the $@%& do you add a property to a plist?

[Thomas S. Dye]

Matt Price <moptop99@gmail.com> writes:

> Hi,
>
> I am continuing to work on my marking stuff; it's working really well,
> actually.
>
> I am currently importing a list of student names and emails from a csv file
> -- this is normally how I get the list of enrolled students.  I have
> modified the defauly settings from our Universities CSV export so I get
> these files in the form:
>
> Student Name,Email
> Student One, em.address@utoronto.ca
> Student Two, em.address2@utoronto.ca
>
> I then parse this into a list, each element of which is itself a list
> ("Student One" "em.address@utoronto.ca"), etc.
>
> This is OK, but not very robust. I would like instead to set *properties*,
> in case the CSV file has some other ordering of fields.  So I've tried this:
>
> (defun parse-plist-csv-file (file)
>   (interactive
>    (list (read-file-name "CSV file: ")))
>   (let ((buf (find-file-noselect file))
>         (result nil))
>     (with-current-buffer buf
>       (goto-char (point-min))
>       (let ((header (split-string  (buffer-substring-no-properties
>                                     (line-beginning-position)
> (line-end-position)) ","))
>             )
>         (while (not (eobp))
>           (let ((line  (split-string (buffer-substring-no-properties
>                                       (line-beginning-position)
> (line-end-position))))
>                 (count 0)
>                 (new-plist '()))
>             (while (< count (length line))
>               (setq plist-new (plist-put new-plist  '(nth count header)
> (nth count line)))
>               (setq count (1+ count)))
>             (push  new-plist result)
>             (forward-line 1))))
>       (reverse result))))
>
> The line that's not working here is:
>
>               (setq plist-new (plist-put new-plist  '(nth count header)
> (nth count line)))
>
> which just inserts nil nil into 'new-plist. Obviously I'm making some
> elementary elsip mistake, but my elisp is too weak to figure it out.  Can
> you guys help?  thanks,
> Matt

According to plist-put's documentation:

(setq x (plist-put x prop val))

(setq new-plist (plist-put new-plist  (nth count header) (nth count line)))
      ^^^^^^^^^                       ^

So, you don't want plist-new, I think.  Also, quoting the first (nth
...)  list means the function nth is interpreted as a value of the list,
rather than a function.  I think you want it to return a property.

I didn't test any of this, so your mmv.

hth,
Tom

-- 
Thomas S. Dye
http://www.tsdye.com