# proposed changes to CSL to permit AGU-style reference sorting

**URL:** <https://discourse.citationstyles.org/t/proposed-changes-to-csl-to-permit-agu-style-reference-sorting/471>\
**Category:** CSL Development\
**Created:** [May 26, 2008, 9:45am UTC](https://discourse.citationstyles.org/t/proposed-changes-to-csl-to-permit-agu-style-reference-sorting/471 "2008-05-26T09:45:14Z")\
**Posts on this page:** 20\
**Page:** 1

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**Author:** ![David\_Kaplan](https://avatars.discourse-cdn.com/v4/letter/d/3ab097/32.png) [@David\_Kaplan](https://discourse.citationstyles.org/u/David_Kaplan)\
**Post date:** [May 26, 2008, 9:45am UTC](https://discourse.citationstyles.org/t/proposed-changes-to-csl-to-permit-agu-style-reference-sorting/471/1 "2008-05-26T09:45:14Z")

</div>

Hi,

I have been working a bit with the Zotero project to improve their AGU  
CSL style so that it matches the AGU style found here:

[http://www.agu.org/pubs/AuthorRefSheet.pdf](http://www.agu.org/pubs/AuthorRefSheet.pdf)

For those of you who are not familiar, the American Geophysical Union is  
a large scientific organization of physicists, materials scientists,  
geologists, oceanographers, etc. It publishes probably about a  
half-dozen to dozen journals. Recent annual meetings have had +10,000  
participants. Furthermore, I am fairly certain similar styles are used  
by a number of other journals. Therefore, I think that CSL should be  
able to support their format.

I believe that the current CSL implementation cannot support some  
elements of the AGU style and therefore would like to propose some  
modifications to CSL. AGU uses what on the surface looks like an  
unusual ordering of references in the bibliography:

1. References are sorted globally by first author.
2. Among references that have the same first author, references with  
just one author come first, ordered by year.
3. Then come references with two authors ordered by second author and  
then year.
4. After this, come references with 3 or more authors. These are sorted  
by just the year of publication, ignoring all but the first author for  
sorting.

This sorting appears strange at first, but it makes some sense as  
citations for articles with more than 2 authors appear in the main text  
as e.g. [Kaplan et al., 2006]. The only info a reader has to locate the  
article is the last name, the fact that is has more than 2 authors, and  
the year. Therefore, it is useful to group publications with several  
authors (same first author) together and order them by year.

Current sorting options don’t really support this as there is no way to  
specify a sorting that depends on the number of authors. We have come  
up with two basic ways that this could be supported, one based on adding  
variables to test for the number of authors, the other based on adding  
options for this style. I personally believe that the first option is a  
much more robust and general approach, but will present both here.

The first option consists of adding a variable “author-count” than can  
be tested for in clauses and adding a way to access just one  
particular author from a list of authors, selecting by number. I am not  
an XML expert, so the code below is just meant to give an idea of how  
this might work, not be grammatically correct:

3

where the macro “first-author” (and similarly for second author) might  
be something like:

...

The other approach to solving the problem would be with additional  
options. For example, one might add:

```
<option name="sort-et-al-min" value="3"/>
<option name="sort-et-al-use-first" value="1"/>

```

While this solution appears more expedient, I think the other approach  
is more robust because:

1. I can imagine and believe there exist slight modifications of this  
format that you will not be able to support without additional options.
2. Adding author-count and the ability to get at particular authors  
would allow you to completely remove several options in favor of macros,  
which are more flexible (e.g., options “et-al-min” and “et-al-use-first”  
could be coded through macros and choose statements (though having “if  
greater than” and “if less than” tests would be very useful as some  
bibliographic styles only use et. al after a large number of references

- e.g., AGU style uses 10)).

1. As option names become more specific, they also become quite obscure  
(related also to the AGU format, we had a discussion about what  
“name-as-sort-order” really means that was quite confusing and is still  
not completely resolved in my mind). Building “options” from macros is  
much easier to understand as it builds complex ideas from simpler ones.
2. Additional options of all types are almost certainly going to creep  
into the format over time as more and more exceptions to the basic  
formats are found. Trying to keep these as limited as possible to just  
those things which cannot be implemented nicely through other approaches  
seems like a good thing.

Cheers,  
David–

* * *

David M. Kaplan  
Charge de Recherche 1  
Institut de Recherche pour le Developpement  
Centre de Recherche Halieutique Mediterraneenne et Tropicale  
av. Jean Monnet  
B.P. 171  
34203 Sete cedex  
France

Phone: +33 (0)4 99 57 32 27  
Fax: +33 (0)4 99 57 32 95  
[http://www.ur097.ird.fr/team/dkaplan/index.html](http://www.ur097.ird.fr/team/dkaplan/index.html)

* * *

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<div class="post-metadata">

**Author:** ![Bruce\_D\_Arcus1](https://avatars.discourse-cdn.com/v4/letter/b/4bbf92/32.png) [@Bruce\_D\_Arcus1](https://discourse.citationstyles.org/u/Bruce_D_Arcus1)\
**Post date:** [May 26, 2008, 12:04pm UTC](https://discourse.citationstyles.org/t/proposed-changes-to-csl-to-permit-agu-style-reference-sorting/471/2 "2008-05-26T12:04:23Z")

</div>

Hi David,

Thanks for the thorough explanation.

Everyone: please read the proposal and tell us what you think. If we  
make this change, I think people need to implement it, or we’ll have  
problems.

My quick response …

> Building “options” from macros is  
> much easier to understand as it builds complex ideas from simpler ones.

True. CSL started without macros, and the current schema reflects some  
of that legacy. With ways to condition formatting based on  
author-count, the et-al options wouldn’t be needed.

One thing, though: we’d probably need to specify exactly what  
“author-count” means. Does it include any primary creators? If we have  
an edited book with one author and two editors (an issue that has come  
up), is the count 1, or is it 3?

Bruce

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<div class="post-metadata">

**Author:** ![David\_Kaplan](https://avatars.discourse-cdn.com/v4/letter/d/3ab097/32.png) [@David\_Kaplan](https://discourse.citationstyles.org/u/David_Kaplan)\
**Post date:** [May 27, 2008, 10:41am UTC](https://discourse.citationstyles.org/t/proposed-changes-to-csl-to-permit-agu-style-reference-sorting/471/3 "2008-05-27T10:41:29Z")

</div>

Hi Bruce,

Regarding what author-count means, you bring up a good point and the  
best thing would be to put as much flexibility as possible in now. In  
some cases, I think author-count will depend on context. For example,  
in AGU style, author-count will be whatever authors appear at the  
beginning of the bibliographic reference. This might be primary  
authors, might be editors, depending on the type of contribution. I  
would suggest somehow developing a way to get at author-count by type of  
author. There should be an author-count for primary authors, an  
author-count for editors, etc., and an author-count summing all of the  
above. We could have a general mechanism at getting at each of these  
and then create macros that would produce the correct result depending  
on context (using substitute and if’s just like in and  
). As I am not an XML expert, can someone else suggest a  
good way to code this?

Cheers,  
David–

* * *

David M. Kaplan  
Charge de Recherche 1  
Institut de Recherche pour le Developpement  
Centre de Recherche Halieutique Mediterraneenne et Tropicale  
av. Jean Monnet  
B.P. 171  
34203 Sete cedex  
France

Phone: +33 (0)4 99 57 32 27  
Fax: +33 (0)4 99 57 32 95  
[http://www.ur097.ird.fr/team/dkaplan/index.html](http://www.ur097.ird.fr/team/dkaplan/index.html)

* * *

---

<div class="post-metadata">

**Author:** ![Bruce\_D\_Arcus1](https://avatars.discourse-cdn.com/v4/letter/b/4bbf92/32.png) [@Bruce\_D\_Arcus1](https://discourse.citationstyles.org/u/Bruce_D_Arcus1)\
**Post date:** [May 27, 2008, 6:25pm UTC](https://discourse.citationstyles.org/t/proposed-changes-to-csl-to-permit-agu-style-reference-sorting/471/4 "2008-05-27T18:25:09Z")

</div>

I’m wondering if a simple approach that builds off existing structures  
might not be best; something like:

\<cs:if variable-count=“author editor”\>…\</cs:if\>

I don’t I have that precisely right, but you get the idea.

Simon? Johan? Ron? Liam?

Need feedback, and a commitment to implement the solution. Otherwise,  
there’ s not much point in adding it.

Bruce

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**Author:** ![Johan\_Kool2](https://avatars.discourse-cdn.com/v4/letter/j/cab0a1/32.png) [@Johan\_Kool2](https://discourse.citationstyles.org/u/Johan_Kool2)\
**Post date:** [May 27, 2008, 10:16pm UTC](https://discourse.citationstyles.org/t/proposed-changes-to-csl-to-permit-agu-style-reference-sorting/471/5 "2008-05-27T22:16:21Z")

</div>

Sorry. A bit of a busy day. I’ll take a look at it tomorrow. I’ve only  
skimmed this discussion, so I am not up to speed as to what exactly is  
needed and how this would and/or could be implemented.

Johan

---

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**Author:** ![Johan\_Kool2](https://avatars.discourse-cdn.com/v4/letter/j/cab0a1/32.png) [@Johan\_Kool2](https://discourse.citationstyles.org/u/Johan_Kool2)\
**Post date:** [May 31, 2008, 11:39am UTC](https://discourse.citationstyles.org/t/proposed-changes-to-csl-to-permit-agu-style-reference-sorting/471/6 "2008-05-31T11:39:51Z")

</div>

Hello,

I’ve at last taken a look at this proposal. I think that this might  
indeed be a good addition to add to CSL to allow for many more other  
oddities being dealt with properly, not just AGU. Though, there is a  
big problem with it to think about carefully.

I like the proposal that adds a variable to each reference best. Maybe  
we should even extend this further beyond just author-count. It would  
just mean that during processing we gather this information for each  
reference and than it can be used in macros for further customization.  
Besides author-count we could perhaps have a count for all other types  
of contributors: editor-count, translator-count etc. Another good  
thing to put in a variable might be the number of the reference is  
cited in the text, the order-number of the first citation, etc.

However, and I think that herein lies the biggest problem, the  
proposed solution changes the sort keys based on the reference being  
sorted. But how do I choose between two references which one goes  
first if their sort-keys are different? There is nothing that ensures  
that the result of both comparisons are the same.

An example:

Ref A: John Doe, 1995, Title A  
Ref B: Mike Jameson, Charles Dickens, 1990, Title B

sort keys ref A:  
by 1st author

sort keys ref B:  
by year

which comes from this CSL, which would be valid if we go by this  
proposal:

....

So which comes first? Ref A or ref B? It is impossible to tell. The  
sort-keys should not change based on one single reference, but on each  
couple of references being compared. I can not write a sorting method  
that adheres to two different sorting-rules at the same time (with  
exception for rules that have the same output, but that is just mere  
coincidence in those cases).

The CSL should say something like: if the author-count of one of the  
references is 1, this reference goes first, if both are one than sort  
by first author. Otherwise, if the author-count of one of the  
references is 2 etc. etc.

I am not sure how that can be said in a good way in CSL. Thought? Do  
you agree with my problem with the sort-keys?

Johan

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<div class="post-metadata">

**Author:** ![Bruce\_D\_Arcus1](https://avatars.discourse-cdn.com/v4/letter/b/4bbf92/32.png) [@Bruce\_D\_Arcus1](https://discourse.citationstyles.org/u/Bruce_D_Arcus1)\
**Post date:** [June 1, 2008, 12:48am UTC](https://discourse.citationstyles.org/t/proposed-changes-to-csl-to-permit-agu-style-reference-sorting/471/7 "2008-06-01T00:48:45Z")

</div>

…

> I like the proposal that adds a variable to each reference best. Maybe  
> we should even extend this further beyond just author-count. It would  
> just mean that during processing we gather this information for each  
> reference and than it can be used in macros for further customization.  
> Besides author-count we could perhaps have a count for all other types  
> of contributors: editor-count, translator-count etc. Another good  
> thing to put in a variable might be the number of the reference is  
> cited in the text, the order-number of the first citation, etc.

Yes, though I think some of that is independent of CSL. And we do now  
have a variable for the citation number.

> However, and I think that herein lies the biggest problem, the  
> proposed solution changes the sort keys based on the reference being  
> sorted. But how do I choose between two references which one goes  
> first if their sort-keys are different? There is nothing that ensures  
> that the result of both comparisons are the same.
> 
> An example:
> 
> Ref A: John Doe, 1995, Title A  
> Ref B: Mike Jameson, Charles Dickens, 1990, Title B
> 
> sort keys ref A:  
> by 1st author
> 
> sort keys ref B:  
> by year
> 
> which comes from this CSL, which would be valid if we go by this  
> proposal:
> 
> ....
> 
> So which comes first? Ref A or ref B? It is impossible to tell. The  
> sort-keys should not change based on one single reference, but on each  
> couple of references being compared. I can not write a sorting method  
> that adheres to two different sorting-rules at the same time (with  
> exception for rules that have the same output, but that is just mere  
> coincidence in those cases).

I’m not entirely following you here Johan.

> The CSL should say something like: if the author-count of one of the  
> references is 1, this reference goes first, if both are one than sort  
> by first author. Otherwise, if the author-count of one of the  
> references is 2 etc. etc.
> 
> I am not sure how that can be said in a good way in CSL. Thought? Do  
> you agree with my problem with the sort-keys?

I just don’t understand it ATM 😉

Bruce

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**Author:** ![Johan\_Kool2](https://avatars.discourse-cdn.com/v4/letter/j/cab0a1/32.png) [@Johan\_Kool2](https://discourse.citationstyles.org/u/Johan_Kool2)\
**Post date:** [June 1, 2008, 1:18pm UTC](https://discourse.citationstyles.org/t/proposed-changes-to-csl-to-permit-agu-style-reference-sorting/471/8 "2008-06-01T13:18:29Z")

</div>

> I just don’t understand it ATM 😉

It is not possible to sort two items when the rules on how to sort are  
changed based on each item being sorted. If I have two items that need  
to be sorted on different rules, it can become impossible to say which  
one comes first. You can only change the sorting rules when you define  
rules on every possible combination of items.

> 3

For the above snippet, say I have two references that I need to sort.  
Which author-count do I use to determine which rules apply? Say one  
reference has 1 author and the other 2. In that case I don’t know  
which set of rules apply. I need to have one set of rules to compare  
each combination of references.

Does this clear it up somewhat?

Johan

---

<div class="post-metadata">

**Author:** ![Bruce\_D\_Arcus1](https://avatars.discourse-cdn.com/v4/letter/b/4bbf92/32.png) [@Bruce\_D\_Arcus1](https://discourse.citationstyles.org/u/Bruce_D_Arcus1)\
**Post date:** [June 1, 2008, 1:43pm UTC](https://discourse.citationstyles.org/t/proposed-changes-to-csl-to-permit-agu-style-reference-sorting/471/9 "2008-06-01T13:43:44Z")

</div>

OK, but step back: it seems you have a problem with the conditional  
within the sort. But given that macro calls are already allowed there,  
is this a new problem?

Just trying to clarify before getting into details …

Bruce

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**Author:** ![Johan\_Kool2](https://avatars.discourse-cdn.com/v4/letter/j/cab0a1/32.png) [@Johan\_Kool2](https://discourse.citationstyles.org/u/Johan_Kool2)\
**Post date:** [June 1, 2008, 2:17pm UTC](https://discourse.citationstyles.org/t/proposed-changes-to-csl-to-permit-agu-style-reference-sorting/471/10 "2008-06-01T14:17:15Z")

</div>

> OK, but step back: it seems you have a problem with the conditional  
> within the sort. But given that macro calls are already allowed there,  
> is this a new problem?

Yes and no. I had actually only just started looking at the sorting  
routines. It is not impossible to have a macro within the sort, but  
than I would use the outcome of the macro resolved to either reference  
and compare those outcomes. I had been thinking to do a better job at  
sorting by not simply resolving the macros but going to look inside  
them for sorting based on the macro content directly. This is for  
example needed when sorting on a macro for author names, or with  
dates. I had indeed been struggling somewhat with the possible  
conditionals there, and this thread now makes it clear to me as to  
why. Conditionals based on a single reference are not possible within  
sort, and so a macro can only be used by simply using its output for  
sorting. I think that this might indeed be a rather confusing thing  
for people writing CSL styles.

Conditionals as are now used in macros are not possible in sort.  
Furthermore, we might want to reconsider using macros as sort keys. I  
think it is much better to actually say that a macro used as a sort  
key, means that the text for that macro gets resolved for each  
reference, which is then sorted alphabetically.

results in:

Jan, 1990  
Feb, 2000  
Apr, 2000

but

\<macro =“month-year”\>

results in:

Apr, 2000  
Feb, 2000  
Jan, 1990

Does Zotero handle macros in the sort already? How? The other  
possibility is to resolve a macro correctly until a conditional is  
encountered and from that point use textual comparison (basing the  
sort on the outcome as text).

I hope my point is clear enough. It is not very easy to put this in  
words so that it is very clear. I hope that at least my problem with  
the conditionals in the sort keys is understandable at this point.

Johan

---

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**Author:** ![Bruce\_D\_Arcus1](https://avatars.discourse-cdn.com/v4/letter/b/4bbf92/32.png) [@Bruce\_D\_Arcus1](https://discourse.citationstyles.org/u/Bruce_D_Arcus1)\
**Post date:** [June 1, 2008, 3:05pm UTC](https://discourse.citationstyles.org/t/proposed-changes-to-csl-to-permit-agu-style-reference-sorting/471/11 "2008-06-01T15:05:18Z")

</div>

> > OK, but step back: it seems you have a problem with the conditional  
> > within the sort. But given that macro calls are already allowed there,  
> > is this a new problem?
> 
> Yes and no. I had actually only just started looking at the sorting  
> routines. It is not impossible to have a macro within the sort, but  
> than I would use the outcome of the macro resolved to either reference  
> and compare those outcomes. I had been thinking to do a better job at  
> sorting by not simply resolving the macros but going to look inside  
> them for sorting based on the macro content directly. This is for  
> example needed when sorting on a macro for author names, or with  
> dates. I had indeed been struggling somewhat with the possible  
> conditionals there, and this thread now makes it clear to me as to  
> why. Conditionals based on a single reference are not possible within  
> sort, and so a macro can only be used by simply using its output for  
> sorting.

Correct; if using a macro for a key, you are using the string  
generated by the macro as the key. I don’'t see any other reasonable  
way.

> I think that this might indeed be a rather confusing thing  
> for people writing CSL styles.
> 
> Conditionals as are now used in macros are not possible in sort.  
> Furthermore, we might want to reconsider using macros as sort keys. I  
> think it is much better to actually say that a macro used as a sort  
> key, means that the text for that macro gets resolved for each  
> reference, which is then sorted alphabetically.
> 
> results in:
> 
> Jan, 1990  
> Feb, 2000  
> Apr, 2000
> 
> but
> 
> \<macro =“month-year”\>
> 
> results in:
> 
> Apr, 2000  
> Feb, 2000  
> Jan, 1990
> 
> Does Zotero handle macros in the sort already? How? The other  
> possibility is to resolve a macro correctly until a conditional is  
> encountered and from that point use textual comparison (basing the  
> sort on the outcome as text).
> 
> I hope my point is clear enough. It is not very easy to put this in  
> words so that it is very clear. I hope that at least my problem with  
> the conditionals in the sort keys is understandable at this point.

So does my answer above help resolve this?

Bruce

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**Author:** ![Johan\_Kool2](https://avatars.discourse-cdn.com/v4/letter/j/cab0a1/32.png) [@Johan\_Kool2](https://discourse.citationstyles.org/u/Johan_Kool2)\
**Post date:** [June 1, 2008, 5:34pm UTC](https://discourse.citationstyles.org/t/proposed-changes-to-csl-to-permit-agu-style-reference-sorting/471/12 "2008-06-01T17:34:58Z")

</div>

> Correct; if using a macro for a key, you are using the string  
> generated by the macro as the key. I don’'t see any other reasonable  
> way.

Good. That’s indeed how I think it should be.

> > I hope that at least my problem with  
> > the conditionals in the sort keys is understandable at this point.
> 
> So does my answer above help resolve this?

Well, your answer means that macro can be used as a key in sort, but  
this does mean also that we still cannot have conditionals in the  
sort. The conditionals in the macro are flattened against each  
reference, and so generate a set of sort rules that is the same for  
each reference. Conditionals directly in the sort still are an  
impossibility. If we want that, we need to come up with a conditional  
that is based on a pair of references.

Something like this, (but then properly thought out):

etc.

The purpose of sort should be that if given two references, it can say  
which one goes first.

Johan

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**Author:** ![Johan\_Kool2](https://avatars.discourse-cdn.com/v4/letter/j/cab0a1/32.png) [@Johan\_Kool2](https://discourse.citationstyles.org/u/Johan_Kool2)\
**Post date:** [June 2, 2008, 9:20pm UTC](https://discourse.citationstyles.org/t/proposed-changes-to-csl-to-permit-agu-style-reference-sorting/471/13 "2008-06-02T21:20:22Z")

</div>

Hello,

I think this could work. We need to add a way to specify the range of  
names to be used for sorting using new attributes start and end. If  
not defined, start=1 and end=infinity. If no names exist at the  
position, it can just use an empty string (which should sort before  
non-empty strings). The macro is used only for the sorting, and is  
solved to its text value for each reference being sorted.

That would give this sorting (I use a semicolon to separate values,  
“”=empty string). This shows the keys some fictional references would  
have and how this sort would turn out:

Doe;1;“”;1997  
Doe;1;“”;1999  
Doe;2;Brown;2004  
Doe;2;Gates;1997  
Doe;2;Gates;2007  
Doe;3;“”;1997  
Doe;3;““2004 (this reference actually has 12 authors!!)  
Doe;3;””;2006

This is all typed in mail, so I might have used some off CSL, but I  
think this principle works. The though bit left to solve is how to  
deal with the condition in the if-tag. I am not sure if putting the  
condition fully inside the condition attribute is best way to do so in  
xml.

JohanOp 2 jun 2008, om 12:26 heeft David M. Kaplan het volgende geschreven:

> Hi,
> 
> I am at a conference at the moment, so I can’t read this too  
> extensively  
> (back next week). I have thought about this problem a bit. That is  
> why  
> I think that adding an “author-count” (maxing out at 3) explicitly to  
> the sort just after the first author would be useful - this should  
> order  
> references correctly. You would also have to sort by each key  
> separately, not just one sort based on a single large text string.
> 
> I also think that perhaps allowing directly in the   
> could  
> be a problem as there is no guarantee to have the same number of keys,  
> which could freak out programs. A better option would be to move the  
> choose to macros (this is not how I framed my initial suggestion,  
> but I  
> think this is better).
> 
> Another problem that I see is context dependent “author-count” - i.e.  
> you want an author count that will be follow clauses so  
> that it will be the number of editors when there is no authors, etc.  
> Framing this correctly seems a bit complicated to me - thoughts?
> 
> Cheers,  
> David
> 
> […]

* * *

> **[Johan Kool](https://johankool.nl/)**
>
> I write apps for iOS and macOS. I am based in Rotterdam, the Netherlands.

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**Author:** ![Bruce\_D\_Arcus1](https://avatars.discourse-cdn.com/v4/letter/b/4bbf92/32.png) [@Bruce\_D\_Arcus1](https://discourse.citationstyles.org/u/Bruce_D_Arcus1)\
**Post date:** [June 2, 2008, 9:43pm UTC](https://discourse.citationstyles.org/t/proposed-changes-to-csl-to-permit-agu-style-reference-sorting/471/14 "2008-06-02T21:43:15Z")

</div>

> Hello,

I forget to get back to you on this, and I’ll need to put it off until  
probably tomorrow sometime, but on this …

> This is all typed in mail, so I might have used some off CSL, but I  
> think this principle works. The though bit left to solve is how to  
> deal with the condition in the if-tag. I am not sure if putting the  
> condition fully inside the condition attribute is best way to do so in  
> xml.

No, it’s not ideal; earlier I’d suggested splitting the variable from  
the condition (“count”) something like:

Bruce

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**Author:** ![Johan\_Kool2](https://avatars.discourse-cdn.com/v4/letter/j/cab0a1/32.png) [@Johan\_Kool2](https://discourse.citationstyles.org/u/Johan_Kool2)\
**Post date:** [June 2, 2008, 10:01pm UTC](https://discourse.citationstyles.org/t/proposed-changes-to-csl-to-permit-agu-style-reference-sorting/471/15 "2008-06-02T22:01:20Z")

</div>

Never mind about that, we are all doing this in our spare time anyway,  
so I understand fully.

Ok, so then if we do the condition like this:

--\> 3,4,5,6,…  
 --\> 0,1,2,3  
 --\> 3  
 --\> 3,4,5,6

we end up with this:

 Op 2 jun 2008, om 23:43 heeft Bruce D'Arcus het volgende geschreven:

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**Author:** ![David\_Kaplan](https://avatars.discourse-cdn.com/v4/letter/d/3ab097/32.png) [@David\_Kaplan](https://discourse.citationstyles.org/u/David_Kaplan)\
**Post date:** [June 9, 2008, 12:23pm UTC](https://discourse.citationstyles.org/t/proposed-changes-to-csl-to-permit-agu-style-reference-sorting/471/16 "2008-06-09T12:23:03Z")

</div>

Hi,

I have been away at a conference, so I haven’t been able to participate  
in the discussion. I just want to weigh in on a couple of issues:

1. I think that conditionals in sort are a bad idea (this may already be  
consensus, but just wanted to add my voice). I would keep conditionals  
in macros and then sort on the macro response as text.

2. At some point there was a suggestion to have conditionals of the  
form:

I think this is a bad idea as it requires parsing the condition text,  
which is a go around using xml (i.e., one should be able to express this  
appropriately in XML so that we can use the XML parser to tell us what  
the condition should look like).

More recently, it has been suggested to use something like:

This is better, but I still think this could have problems. One is that  
I am not sure how substitution would work with this (for example, if  
instead of authors, the publication had editors, how would the know  
to use editors instead of authors?). You could probably work this out  
with lots of if’s, but it is a bit awkward.

The other problem is that I think it would be more flexible to have a  
general way of expressing basic conditions in CSL and then apply this  
appropriately. Someone must have already drafted how statements  
could be done in general XML, and we should probably take advantage of  
this knowledge. But, it could go something like this:

 3 ....

This would be equivalent to “if (author-count \> 3) {}” (in essence this  
is using XML to pre-parse the conditional statement).

The macro would be something like:

 0 

This is just a guess as to the best way to do this, but the basic idea  
of using XML to express the condition I think is the right direction.

Note, if you did this, you could get rid of in favor of  
appropriate if statements, but it is not clear this be particularly more  
effective than what is already in CSL.

Cheers,  
David–

* * *

David M. Kaplan  
Charge de Recherche 1  
Institut de Recherche pour le Developpement  
Centre de Recherche Halieutique Mediterraneenne et Tropicale  
av. Jean Monnet  
B.P. 171  
34203 Sete cedex  
France

Phone: +33 (0)4 99 57 32 27  
Fax: +33 (0)4 99 57 32 95  
[http://www.ur097.ird.fr/team/dkaplan/index.html](http://www.ur097.ird.fr/team/dkaplan/index.html)

* * *

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**Author:** ![David\_Kaplan](https://avatars.discourse-cdn.com/v4/letter/d/3ab097/32.png) [@David\_Kaplan](https://discourse.citationstyles.org/u/David_Kaplan)\
**Post date:** [June 9, 2008, 3:16pm UTC](https://discourse.citationstyles.org/t/proposed-changes-to-csl-to-permit-agu-style-reference-sorting/471/17 "2008-06-09T15:16:49Z")

</div>

Hi,

I have been consulting with some friends that know a thing or two about  
XML. They basically pointed me to XSL and wondered why CSL was  
developed as a separate language and didn’t just use XSL instead? I  
imagine from looking a bit at XSL that it was like using a bulldozer to  
crack an egg open.

XSL has conditionals, but they do exactly what I recommended not doing  
by placing the condition in a separate language called XPath:

[http://www.w3.org/TR/xslt#section-Conditional-Processing-with-xsl:if](http://www.w3.org/TR/xslt#section-Conditional-Processing-with-xsl:if)

I am not sure this is the direction we should go in, but XSL is a  
standard. However, our needs seem much more limited than general XSL  
and it would seem that developing a simple condition like I  
suggested is a good idea. But I defer to someone who has a more global  
vision of how zotero works with CSL and the logic behind the structure  
of CSL.

Cheers,  
David\> I you know of any “prior art” on this, I sure like to know. I haven’t

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<div class="post-metadata">

**Author:** ![Bruce\_D\_Arcus1](https://avatars.discourse-cdn.com/v4/letter/b/4bbf92/32.png) [@Bruce\_D\_Arcus1](https://discourse.citationstyles.org/u/Bruce_D_Arcus1)\
**Post date:** [June 9, 2008, 10:44pm UTC](https://discourse.citationstyles.org/t/proposed-changes-to-csl-to-permit-agu-style-reference-sorting/471/18 "2008-06-09T22:44:44Z")

</div>

Exactly!

There are a lot of reasons why not XSLT. First, take a look at the APA  
style that Microsoft implements in Word 2007/2008 and compare it to  
our’s. There’s something like an order-of-magnitude difference in size  
(and complexity), and our’s better implements the style.

Second, XSLT is designed for XML input formats; CSL is intended to be  
agnostic about that.

Bruce

---

<div class="post-metadata">

**Author:** ![Bruce\_D\_Arcus1](https://avatars.discourse-cdn.com/v4/letter/b/4bbf92/32.png) [@Bruce\_D\_Arcus1](https://discourse.citationstyles.org/u/Bruce_D_Arcus1)\
**Post date:** [June 9, 2008, 10:58pm UTC](https://discourse.citationstyles.org/t/proposed-changes-to-csl-to-permit-agu-style-reference-sorting/471/19 "2008-06-09T22:58:15Z")

</div>

> More recently, it has been suggested to use something like:
> 
> This is better, but I still think this could have problems. One is that  
> I am not sure how substitution would work with this (for example, if  
> instead of authors, the publication had editors, how would the know  
> to use editors instead of authors?). You could probably work this out  
> with lots of if’s, but it is a bit awkward.

The way we do it now is the content of the conditional “type”  
attribute is a list; so one ore more.

> The other problem is that I think it would be more flexible to have a  
> general way of expressing basic conditions in CSL and then apply this  
> appropriately. Someone must have already drafted how statements  
> could be done in general XML, and we should probably take advantage of  
> this knowledge. But, it could go something like this:
> 
> 3 ....
> 
> This would be equivalent to “if (author-count \> 3) {}” (in essence this  
> is using XML to pre-parse the conditional statement).
> 
> The macro would be something like:
> 
> 0

Hmm … WRT the conditional, that’s not even necessary now. Our  
default (implicit) match condition is to test whether a variable is  
present. So there’s no need to do the \> 0 test.

The trick here is really how best to grab the count.

Maybe:

The “author-count” thing is maybe a bit ugly though.

Bruce

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**Author:** ![Bruce\_D\_Arcus1](https://avatars.discourse-cdn.com/v4/letter/b/4bbf92/32.png) [@Bruce\_D\_Arcus1](https://discourse.citationstyles.org/u/Bruce_D_Arcus1)\
**Post date:** [June 9, 2008, 10:59pm UTC](https://discourse.citationstyles.org/t/proposed-changes-to-csl-to-permit-agu-style-reference-sorting/471/20 "2008-06-09T22:59:22Z")

</div>

Oops; which is implemented in XSLT.

Bruce

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