numbered equations in html export

numbered equations in html export

[Eric Schulte]

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Hi,

All equations are numbered "1" when the attached example file is
exported to HTML.


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#+Title: Example

* H1
See Equation [[the-first]],

#+name: the-first
\begin{equation}
n_{i+1} = \frac{n_{i} (d-i) (e-1)}{(i+1)}
\end{equation}

and also Equation [[the-second]].

#+name: the-second
\begin{equation}
n_{0} = 1
\end{equation}


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Thanks,

-- 
Eric Schulte
https://cs.unm.edu/~eschulte
PGP: 0x614CA05D (see https://u.fsf.org/yw)

Re: numbered equations in html export

[Nicolas Goaziou]

Hello,

Eric Schulte <schulte.eric@gmail.com> writes:

> All equations are numbered "1" when the attached example file is
> exported to HTML.
>
> #+Title: Example
>
> * H1
> See Equation [[the-first]],
>
> #+name: the-first
> \begin{equation}
> n_{i+1} = \frac{n_{i} (d-i) (e-1)}{(i+1)}
> \end{equation}
>
> and also Equation [[the-second]].
>
> #+name: the-second
> \begin{equation}
> n_{0} = 1
> \end{equation}

Only captioned equations are numbered. Behaviour is undefined for other
equations.


Regards,

-- 
Nicolas Goaziou

Re: numbered equations in html export

[Eric Schulte]

Nicolas Goaziou <mail@nicolasgoaziou.fr> writes:

> Hello,
>
> Eric Schulte <schulte.eric@gmail.com> writes:
>
>> All equations are numbered "1" when the attached example file is
>> exported to HTML.
>>
>> #+Title: Example
>>
>> * H1
>> See Equation [[the-first]],
>>
>> #+name: the-first
>> \begin{equation}
>> n_{i+1} = \frac{n_{i} (d-i) (e-1)}{(i+1)}
>> \end{equation}
>>
>> and also Equation [[the-second]].
>>
>> #+name: the-second
>> \begin{equation}
>> n_{0} = 1
>> \end{equation}
>
> Only captioned equations are numbered. Behaviour is undefined for other
> equations.
>

Why is this the default behavior?  It looks to me like even when they're
present captions on equations aren't displayed for HTML or LaTeX export.
Additionally I don't see why captions should be related to, or required
for, the numbering of equations.

In a related issue which I believe is more convincingly a bug; links to
equations (whether numbered or not, with or without captions) don't
actually point anywhere.  A link to the name is constructed, but no
anchor with the name is inserted into the page.

Would it make sense to change the current behavior as follows?

1. On HTML export all named equations are made into targets for a link
   based on their name.

2. All named and referenced equations are numbered.

Thanks,

>
>
> Regards,

-- 
Eric Schulte
https://cs.unm.edu/~eschulte
PGP: 0x614CA05D (see https://u.fsf.org/yw)

Re: numbered equations in html export

[Nicolas Goaziou]

Hello,

Eric Schulte <schulte.eric@gmail.com> writes:

> Nicolas Goaziou <mail@nicolasgoaziou.fr> writes:

>> Only captioned equations are numbered. Behaviour is undefined for other
>> equations.

> Why is this the default behavior?  It looks to me like even when they're
> present captions on equations aren't displayed for HTML or LaTeX export.

LaTeX export uses its own numbering mechanism over which Org has no
control. It is true that captions are not used in latex environments,
but that's orthogonal to the problem. Let's put it aside for now.

HTML export relies on Org's mechanism to number objects (i.e.,
`org-export-get-ordinal'). It conforms to numbering rules of other
elements, like tables. It is important for tables to require a caption.
Otherwise, a list of tables would have non-consecutive numbers.
Equations are consistent with this.

> Additionally I don't see why captions should be related to, or required
> for, the numbering of equations.

It is odd to reference a number used nowhere. For example, it is
confusing to follow an "equation 2" link and see a page full of
equations with no attached number below.

Admittedly, this point is moot as long as captions are not visible on
latex environments. I think this should be fixed instead.

Another advantage is that you can always link to an unnumbered equation
(just providing a name and no caption), which would not be possible if
every named equation was numbered.

> In a related issue which I believe is more convincingly a bug; links to
> equations (whether numbered or not, with or without captions) don't
> actually point anywhere.  A link to the name is constructed, but no
> anchor with the name is inserted into the page.

This looks like a limitation from `org-html-latex-environment' (there
is a comment about it) due to mathjax handling.

> Would it make sense to change the current behavior as follows?
>
> 1. On HTML export all named equations are made into targets for a link
>    based on their name.

It makes sense, there is just mathjax case to handle. It could go along
with your other patch protecting characters, as a special treatment
related to mathjax.

> 2. All named and referenced equations are numbered.

IMO it would be more sensible to handle captions for equations, for the
reasons explained above.


Regards,

-- 
Nicolas Goaziou

Re: numbered equations in html export

[Nick Dokos]

Nicolas Goaziou <mail@nicolasgoaziou.fr> writes:

>> Additionally I don't see why captions should be related to, or required
>> for, the numbering of equations.
>
> It is odd to reference a number used nowhere. For example, it is
> confusing to follow an "equation 2" link and see a page full of
> equations with no attached number below.
>
> Admittedly, this point is moot as long as captions are not visible on
> latex environments. I think this should be fixed instead.
>

Not sure I understand correctly: are you saying that in the latex output
every numbered equation would then have a visible caption?

-- 
Nick

Re: numbered equations in html export

[Nicolas Goaziou]

Nick Dokos <ndokos@gmail.com> writes:

> Nicolas Goaziou <mail@nicolasgoaziou.fr> writes:
>
>> Admittedly, this point is moot as long as captions are not visible on
>> latex environments. I think this should be fixed instead.
>>
>
> Not sure I understand correctly: are you saying that in the latex output
> every numbered equation would then have a visible caption?

No I'm not. I suggested to ignore latex export back-end since it has its
own numbering mechanism. I'm saying that in HTML output, numbering LaTeX
equations could be done through captions.

It is also possible to not use captions but, instead, regular numbering
with appropriate LaTeX environments or macros (e.g., \tag{x}). But then,
export engine cannot possibly be aware of that, so relying on #+NAME to
get an equation number is bound to fail.


Regards,

-- 
Nicolas Goaziou

Re: numbered equations in html export

[Nick Dokos]

Nicolas Goaziou <mail@nicolasgoaziou.fr> writes:

> Nick Dokos <ndokos@gmail.com> writes:
>
>> Nicolas Goaziou <mail@nicolasgoaziou.fr> writes:
>>
>>> Admittedly, this point is moot as long as captions are not visible on
>>> latex environments. I think this should be fixed instead.
>>>
>>
>> Not sure I understand correctly: are you saying that in the latex output
>> every numbered equation would then have a visible caption?
>
> No I'm not. I suggested to ignore latex export back-end since it has its
> own numbering mechanism. I'm saying that in HTML output, numbering LaTeX
> equations could be done through captions.
>
> It is also possible to not use captions but, instead, regular numbering
> with appropriate LaTeX environments or macros (e.g., \tag{x}). But then,
> export engine cannot possibly be aware of that, so relying on #+NAME to
> get an equation number is bound to fail.
>

OK - thanks.

Nick