Re: CSL-JSON support for =parsebib=

[Joost Kremers <joostkremers@fastmail.fm>]

On Fri, May 07 2021, Titus von der Malsburg wrote:
>> Apparently, =json-parse-{buffer|string}= then gives you a symbol with a space
>> in it...
>
> I now see that symbol names “can contain any characters whatever” [1]. But many
> characters need to be escaped (like spaces) which isn’t pretty.

Agreed. But if you pass such a symbol to =symbol-name= or to =(format "%s")=,
the escape character is removed, so when it comes to displaying those symbols to
users, it shouldn't matter much.

Note, though, that the keys in CSL-JSON don't seem to contain any spaces or
other weird characters. There are just lower case a-z and dash, that's all.

>> This works for the Elisp library =json.el=, but Emacs 27 can be compiled with
>> native JSON support, which, however, doesn't provide this option,
>> unfortunately.
>
> I see. In this case it might make sense to propose string keys as a feature for
> json.c. The key is a string anyway at some point during parsing, so avoiding the
> conversion to symbol may actually be the best way to speed things up.

True. I'll ask on emacs-devel. Personally, I'd prefer strings, too, but I'm a
bit hesitant about doing the conversion myself, esp. given that in Ebib, all the
keys would need to be converted back before I can save a file.

>> That would be easy to support, but IMHO is better handled in
>> bibtex-completion:
>> just parse the buffer and then call =gethash= on the resulting hash table. Or
>> what use-case do you have in mind?
>
> One use case: bibtex-completion drops fields that aren’t needed early on to save
> memory and CPU cycles. (Some people work with truly enormous bibliographies,
> like crypto.bib with ~60K entries.) But this means that we sometimes have to
> read an individual entry again if we need more fields that were dropped earlier.
> In this case I’d like to be able to read just one entry without having to
> reparse the complete bibliography.

Makes sense. For .bib sources, this should be fairly easy to do. For .json, I
can't really say how easy it would be. It's not difficult to find the entry key
in the buffer, but from there you'd have to be able to find the start of the
entry in order to parse it. Currently, I don't know how to do that.

>>> - Functions for resolving strings and cross-references.
[...]
>> parsebib has a lower-level API and a higher-level API, and the latter does
>> essentially what you suggest here. I thought bibtex-completion was already
>> using it...
>
> Nope. I think the high-level API didn’t exist when I wrote my code in 2014.

No, it didn't. I seem to remember, though, that you gave me the idea for the
higher-level API, which is probably why I assumed you were using it.

So that part of =parsebib= hasn't been tested much... (Ebib doesn't use it,
either). If you do decide to start using it, please test it and report any
issues you find. And let me know if I can help with testing.


-- 
Joost Kremers
Life has its moments