export to latex without labels

export to latex without labels

[Salome =?iso-8859-1?Q?S=F6dergran ?=]

Hello experts,

I've been fiddling around for a while now with the following problem:

When I export something from org to latex I get plenty of \labels that I never refer to. I'd like to get rid of all those labels.
I found some code [1] that uses a hook that does not work in orgmode anymore. So I tried to adapt that code to the new orgmode way with org-export-filter-final-functions:

(defun ks/org-latex-remove-labels (backend info)
  "Remove labels generated by org-mode"
  (when (org-export-derived-backend-p backend 'latex)
  (let ((case-fold-search nil))
   (goto-char 1)
   (replace-regexp "\\\\label{sec-[0-9][^}]*}" "")
   )))

(eval-after-load 'ox-latex
  '(add-to-list 'org-export-filter-final-output-functions
            'ks/org-latex-remove-labels))


When I now try to export something from org to latex, I get the following error message:
 Wrong number of arguments: (lambda (backend) "Remove labels generated by org-mode" (if (org-export-derived-backend-p backend (quote latex)) (progn (let ((case-fold-search nil)) (goto-char 1) (replace-regexp "\\\\label{sec-[0-9][^}]*}" ""))))), 3

I am just an emacs user, not a programmer, and I have no idea what's wrong and what I have to change to make it work. Can anyone give me a hint?
TIA, Salome


[1] http://stackoverflow.com/questions/18076328/org-mode-export-to-latex-suppress-generation-of-labels 

Re: export to latex without labels

[Eric Abrahamsen]

"Salome "Södergran\"" <salome.soedergran@gmx.ch> writes:

> Hello experts,
>
> I've been fiddling around for a while now with the following problem:
>
> When I export something from org to latex I get plenty of \labels that I never refer to. I'd like to get rid of all those labels.
> I found some code [1] that uses a hook that does not work in orgmode anymore. So I tried to adapt that code to the new orgmode way with org-export-filter-final-functions:
>
> (defun ks/org-latex-remove-labels (backend info)
>   "Remove labels generated by org-mode"
>   (when (org-export-derived-backend-p backend 'latex)
>   (let ((case-fold-search nil))
>    (goto-char 1)
>    (replace-regexp "\\\\label{sec-[0-9][^}]*}" "")
>    )))
>
> (eval-after-load 'ox-latex
>   '(add-to-list 'org-export-filter-final-output-functions
>             'ks/org-latex-remove-labels))
>
>
> When I now try to export something from org to latex, I get the following error message:
>  Wrong number of arguments: (lambda (backend) "Remove labels generated by org-mode" (if (org-export-derived-backend-p backend (quote latex)) (progn (let ((case-fold-search nil)) (goto-char 1) (replace-regexp "\\\\label{sec-[0-9][^}]*}" ""))))), 3
>
> I am just an emacs user, not a programmer, and I have no idea what's wrong and what I have to change to make it work. Can anyone give me a hint?
> TIA, Salome

The error message is telling you that the wrong number of arguments were
passed to your filter function. If you look at the doctoring of
org-export-filter-final-output-functions, you'll see that functions in
this filter are passed three arguments (note the 3 at the end of your
error message), but your function only accepts two.

Once you've sorted that out, you'll see that the argument you're missing
is an argument representing the full exported string. That means that
`replace-regexp' is probably the wrong function to be using inside your
function. Actually, if you look at the docstring of replace-regexp, that
was the wrong function to be using anyway :) It recommends using a
combination of re-search-forward and replace-match in lisp functions.

Since you've got a string, try replace-regexp-in-string instead! See the
docstring...

Lastly, it's possible that you could use a more narrowly-targeted filter
for this particular case (rather than filter-final-output, which doesn't
kick in until everything else is done). When exporting to latex, the
element that turns into \label is a target, and that happens in
org-latex-target. The corresponding filter is
org-export-filter-target-functions, so you might consider putting your
function in that variable instead. That could be much simpler: the
function would take three arguments, the second of which is the backend,
as a symbol. You could just check if the symbol was 'latex, and have the
function return an empty string. The function body could be as simple
as:

(defun org-latex-remove-labels (string backend data)
  (if (org-export-derived-backend-p backend 'latex)
      ""
    string))

I haven't tested this for unexpected consequences, mind you...

Really really lastly, does it really matter if there are unused \labels
in the output?

E

Re: export to latex without labels

[Eric Abrahamsen]

Eric Abrahamsen <eric@ericabrahamsen.net> writes:

> "Salome "Södergran\"" <salome.soedergran@gmx.ch> writes:
>
>> Hello experts,
>>
>> I've been fiddling around for a while now with the following problem:
>>
>> When I export something from org to latex I get plenty of \labels that I never refer to. I'd like to get rid of all those labels.
>> I found some code [1] that uses a hook that does not work in orgmode anymore. So I tried to adapt that code to the new orgmode way with org-export-filter-final-functions:
>>
>> (defun ks/org-latex-remove-labels (backend info)
>>   "Remove labels generated by org-mode"
>>   (when (org-export-derived-backend-p backend 'latex)
>>   (let ((case-fold-search nil))
>>    (goto-char 1)
>>    (replace-regexp "\\\\label{sec-[0-9][^}]*}" "")
>>    )))
>>
>> (eval-after-load 'ox-latex
>>   '(add-to-list 'org-export-filter-final-output-functions
>>             'ks/org-latex-remove-labels))
>>
>>
>> When I now try to export something from org to latex, I get the following error message:
>>  Wrong number of arguments: (lambda (backend) "Remove labels generated by org-mode" (if (org-export-derived-backend-p backend (quote latex)) (progn (let ((case-fold-search nil)) (goto-char 1) (replace-regexp "\\\\label{sec-[0-9][^}]*}" ""))))), 3
>>
>> I am just an emacs user, not a programmer, and I have no idea what's wrong and what I have to change to make it work. Can anyone give me a hint?
>> TIA, Salome
>
> The error message is telling you that the wrong number of arguments were
> passed to your filter function. If you look at the doctoring of
> org-export-filter-final-output-functions, you'll see that functions in
> this filter are passed three arguments (note the 3 at the end of your
> error message), but your function only accepts two.
>
> Once you've sorted that out, you'll see that the argument you're missing
> is an argument representing the full exported string. That means that
> `replace-regexp' is probably the wrong function to be using inside your
> function. Actually, if you look at the docstring of replace-regexp, that
> was the wrong function to be using anyway :) It recommends using a
> combination of re-search-forward and replace-match in lisp functions.
>
> Since you've got a string, try replace-regexp-in-string instead! See the
> docstring...
>
> Lastly, it's possible that you could use a more narrowly-targeted filter
> for this particular case (rather than filter-final-output, which doesn't
> kick in until everything else is done). When exporting to latex, the
> element that turns into \label is a target, and that happens in
> org-latex-target. The corresponding filter is
> org-export-filter-target-functions, so you might consider putting your
> function in that variable instead. That could be much simpler: the
> function would take three arguments, the second of which is the backend,
> as a symbol. You could just check if the symbol was 'latex, and have the
> function return an empty string. The function body could be as simple
> as:
>
> (defun org-latex-remove-labels (string backend data)
>   (if (org-export-derived-backend-p backend 'latex)
>       ""
>     string))
>
> I haven't tested this for unexpected consequences, mind you...
>
> Really really lastly, does it really matter if there are unused \labels
> in the output?

Hmm, that might have been too much information. What I'm proposing is
just this:

(defun ks/org-latex-remove-labels (string backend info)
  "Remove labels generated by org-mode"
  (if (org-export-derived-backend-p backend 'latex)
      ""
    string))

(eval-after-load 'ox-latex
  '(add-to-list 'org-export-filter-target-functions
            'ks/org-latex-remove-labels))

Re: export to latex without labels

[Nick Dokos]

Eric Abrahamsen <eric@ericabrahamsen.net> writes:

> "Salome "Södergran\"" <salome.soedergran@gmx.ch> writes:
>
>> Hello experts,
>>
>> I've been fiddling around for a while now with the following problem:
>>
>> When I export something from org to latex I get plenty of \labels
>> that I never refer to. I'd like to get rid of all those labels.
>> ...
>
> ...
> Really really lastly, does it really matter if there are unused \labels
> in the output?
>

What he said: stop worrying and (let org export) label everything :-)

In a similar vein, in N. David Mermin's *wonderful* book "Boojums all
the way through", there is a chapter entitled "What's wrong with these
equations?" (the article is available on line at
http://www.ai.mit.edu/courses/6.899/papers/mermin.pdf - but the whole
book is worth reading) where he mentions Fisher's rule: number *every*
equation in your manuscript.
-- 
Nick

Re: export to latex without labels

[Salome Soedergran]

Hi Eric,

Eric Abrahamsen <eric@ericabrahamsen.net> writes:
> The error message is telling you that the wrong number of arguments were
> passed to your filter function. If you look at the doctoring of
> org-export-filter-final-output-functions, you'll see that functions in
> this filter are passed three arguments (note the 3 at the end of your
> error message), but your function only accepts two.
> 
> Once you've sorted that out, you'll see that the argument you're missing
> is an argument representing the full exported string. That means that
> `replace-regexp' is probably the wrong function to be using inside your
> function. Actually, if you look at the docstring of replace-regexp, that
> was the wrong function to be using anyway :) It recommends using a
> combination of re-search-forward and replace-match in lisp functions.
> 
> Since you've got a string, try replace-regexp-in-string instead! See the
> docstring...
> 
> Lastly, it's possible that you could use a more narrowly-targeted filter
> for this particular case (rather than filter-final-output, which doesn't
> kick in until everything else is done). When exporting to latex, the
> element that turns into \label is a target, and that happens in
> org-latex-target. The corresponding filter is
> org-export-filter-target-functions, so you might consider putting your
> function in that variable instead. That could be much simpler: the
> function would take three arguments, the second of which is the backend,
> as a symbol. You could just check if the symbol was 'latex, and have the
> function return an empty string. The function body could be as simple
> as:
> 
> (defun org-latex-remove-labels (string backend data)
>   (if (org-export-derived-backend-p backend 'latex)
>       ""
>     string))
> 
> I haven't tested this for unexpected consequences, mind you...
> 
> Really really lastly, does it really matter if there are unused \labels
> in the output?
> 
[...]
> Hmm, that might have been too much information. What I'm proposing is
> just this:
> 
> (defun ks/org-latex-remove-labels (string backend info)
>   "Remove labels generated by org-mode"
>   (if (org-export-derived-backend-p backend 'latex)
>       ""
>     string))
> 
> (eval-after-load 'ox-latex
>   '(add-to-list 'org-export-filter-target-functions
>             'ks/org-latex-remove-labels))
> 

Thank you so much for your explanations! That was NOT too much information but exactly what I'd been hoping for. It's this sort of information that helps me to come to a better understanding of emacs.
I have tested your suggestion with just no result whatsoever. But with the help of your explanations I've managed to change my bit of code accordingly and now it works:
(defun ks/org-latex-remove-labels (string backend info)
  "Remove labels generated by org-mode"
  (when (org-export-derived-backend-p backend 'latex)
  (let ((case-fold-search nil))
   (goto-char 1)
   (replace-regexp-in-string "\\\\label{sec-[0-9][^}]*}\n" "" string)
   )))
(eval-after-load 'ox-latex
  '(add-to-list 'org-export-filter-final-output-functions
            'ks/org-latex-remove-labels))

Thanks again! Salome

Re: export to latex without labels

[Eric Abrahamsen]

"Salome Soedergran" <salome.soedergran@gmx.ch> writes:

> Hi Eric,
>
> Eric Abrahamsen <eric@ericabrahamsen.net> writes:
>> The error message is telling you that the wrong number of arguments were
>> passed to your filter function. If you look at the doctoring of
>> org-export-filter-final-output-functions, you'll see that functions in
>> this filter are passed three arguments (note the 3 at the end of your
>> error message), but your function only accepts two.
>> 
>> Once you've sorted that out, you'll see that the argument you're missing
>> is an argument representing the full exported string. That means that
>> `replace-regexp' is probably the wrong function to be using inside your
>> function. Actually, if you look at the docstring of replace-regexp, that
>> was the wrong function to be using anyway :) It recommends using a
>> combination of re-search-forward and replace-match in lisp functions.
>> 
>> Since you've got a string, try replace-regexp-in-string instead! See the
>> docstring...
>> 
>> Lastly, it's possible that you could use a more narrowly-targeted filter
>> for this particular case (rather than filter-final-output, which doesn't
>> kick in until everything else is done). When exporting to latex, the
>> element that turns into \label is a target, and that happens in
>> org-latex-target. The corresponding filter is
>> org-export-filter-target-functions, so you might consider putting your
>> function in that variable instead. That could be much simpler: the
>> function would take three arguments, the second of which is the backend,
>> as a symbol. You could just check if the symbol was 'latex, and have the
>> function return an empty string. The function body could be as simple
>> as:
>> 
>> (defun org-latex-remove-labels (string backend data)
>>   (if (org-export-derived-backend-p backend 'latex)
>>       ""
>>     string))
>> 
>> I haven't tested this for unexpected consequences, mind you...
>> 
>> Really really lastly, does it really matter if there are unused \labels
>> in the output?
>> 
> [...]
>> Hmm, that might have been too much information. What I'm proposing is
>> just this:
>> 
>> (defun ks/org-latex-remove-labels (string backend info)
>>   "Remove labels generated by org-mode"
>>   (if (org-export-derived-backend-p backend 'latex)
>>       ""
>>     string))
>> 
>> (eval-after-load 'ox-latex
>>   '(add-to-list 'org-export-filter-target-functions
>>             'ks/org-latex-remove-labels))
>> 
>
> Thank you so much for your explanations! That was NOT too much information but exactly what I'd been hoping for. It's this sort of information that helps me to come to a better understanding of emacs.
> I have tested your suggestion with just no result whatsoever. But with
> the help of your explanations I've managed to change my bit of code
> accordingly and now it works:

Yes, that's the danger with totally untested suggestions :) Turns out
the \labels are hard-coded, and the "target" stuff is something else
entirely.

Glad you got it working, despite that!

> (defun ks/org-latex-remove-labels (string backend info)
>   "Remove labels generated by org-mode"
>   (when (org-export-derived-backend-p backend 'latex)
>   (let ((case-fold-search nil))
>    (goto-char 1)
>    (replace-regexp-in-string "\\\\label{sec-[0-9][^}]*}\n" "" string)
>    )))
> (eval-after-load 'ox-latex
>   '(add-to-list 'org-export-filter-final-output-functions
>             'ks/org-latex-remove-labels))
>
> Thanks again! Salome