Hi,
This is a proposal about how thorns can provide citations of resources (papers, ...), and how Cactus could use those to output a list of 'used resources'.
I would like to make this the topic for the October-hack-a-day, if I find one or two more interested people. It shouldn't take more than that day to get something working. Before that, however, we should discuss what this should actually look like.
The rest of this email is details about the proposal. If you are not interested, you can stop reading here. If you are, please let us know what you think after you've read it.
While I said 'resources', I mean citations, usually to papers, but really it could be anything.
There is also the question of how to cite something, and in the following I am assuming bibtex entries, as that is what most likely most people would find useful.
First of all, thorns would need to have a way to provide citations. Thorns already provide all kinds of stuff, and most of that is 'announced to Cactus' in configuration.ccl, so let's use that, and not create yet another .ccl file:
PROVIDES CITATION name AS "xyz" PROVIDES CITATION name IN bibtex filename, relative to thorn dir REQUIRES CITATION name
This gives each citation a name, and would use that in a key-value table as key, where the value is a bibtex-entry, verbatim and (in this proposal) unparsed by Cactus. The name should ideally be the same as the key in the bibtex entry, but it doesn't need to be. We could decide to enforce equality, but then would have to parse the entry / bib file.
This mechanism would only provide a way to define citations, and use them if you can be sure another thorn already provides it (REQUIRES).
The next question would be how to tell Cactus that a certain citation should be included in the output, and what that output should look like. We already have two "classes" of citations in the ET: "requested" and "optional". "requested" citations should be cited whenever that piece of code was used, while "optional" are, well, optional. Thus, we should have a way to provide those. Also, whether a citation should be included might depend on parameters (we do have a few examples of those), and not just thorn activation. Thus, I believe the best way to include this is
schedule.ccl:
CITATION name CITATION OPTIONAL name
These could be stand-alone, top-level statements, or be inside if-blocks, similar to, e.g., STORAGE statements. These statements only use the name of the citation as defined above - not the actual citation string itself.
Once a citation is marked as 'being used', it will not be 'unmarked' within that run.
Using this information, Cactus will then provide output regarding which citations are used, by which thorn, and of which type (requested, optional). This output is updated (overwritten) each time something is added (but waits until the regular thorn-activation sequence is completed).
The output should, at least, consist of: - one bibtex file containing all known entries - two lists of keys, in machine readable format: requested/optional - machine readable information about which thorn requested what how
Of course, depending on our wishes, part of this can and should be configurable via parameters.
Frank Loeffler