From: Nicolas Goaziou <firstname.lastname@example.org> To: Org Mode List <email@example.com> Subject: (Not so) Short note about citations in Org Date: Thu, 22 Apr 2021 01:34:03 +0200 [thread overview] Message-ID: <firstname.lastname@example.org> (raw) Hello, I just rebased "wip-cite-new" branch, which now includes citation syntax, and an interface between external citation processors and the rest of Org. I'll throw in a demo at the end of this message. TL;DR: search for "Demo time". As a reminder, the full citation syntax is [cite/style:common prefix ;prefix -@key suffix; ... ; common suffix] Everything is optional, except the brackets, "cite" and the colon. Also the citation must contain at least a key. So its minimal form is: [cite:@key] or its "suppress author" variant: [cite:-@key] A noteworthy difference with the last merge is that I removed the opportunity to add some Org syntax (emphasis, sub/superscript…) in prefixes or suffixes. It makes the code a bit simpler. Of course, I'm open to discussion about this change. The syntax also introduces three keywords (square brackets are for optional arguments): #+bibliography: filename #+print_bibliography: [style] #+cite_export: backend-name [bibliography-style] [citation-style] Now, the real novelty is the new "oc.el" library, which is an API to operate simply on citations. I paste here its commentary section. This library provides tooling to handle citations in Org, e.g, follow, fontify, and export them, respectively called "follow", "activate" and "export" capabilities. Libraries responsible for providing some, or all, of these capabilities are called "citation processors". Such processors are defined using `org-cite-register-processor'. Using this function, it is possible, in addition to giving it a name, to attach functions associated to capabilities. As such, a processor handling citation export must set the `:export-citation' property to an appropriate function. Likewise, "activate" capability require an appropriate `:activate' property, and, unsurprisingly, "follow" capability implies `:follow' property. As a user, the first thing to do is setting a bibliography, either globally with `org-cite-global-bibliography', or locally using one ore more "bibliography" keywords. Then one can select any registered processor for each capability by providing a processor name to the variables `org-cite-activate-processor' and `org-cite-follow-processor'. The "export" capability is slightly more involved as one need to select the processor providing it, but may also provide a default style for citations and bibliography. These three parameters, or triplet, can be set in `org-cite-export-processor' variable, or in a document, through the "cite_export" keyword. Eventually, this library provides some tools, mainly targeted at processor implementors. Most are export-specific and are located in the "Tools only available during export" section. The few others can be used directly from an Org buffer, or operate on processors. See "Generic tools" section. There are two points of view to consider here. As a user, as stated above, you first need to provide a bibliography, for all documents using the `org-cite-global-bibliography' variable, or for a single document (or a set of documents, using "setupfile" keyword) with #+bibliography: one-file.bib #+bibliography: another-file.ext #+bibliography: "some file with spaces" You can use both the variable and the keywords, in which case files are _accumulated_ in the list. Then when you (require 'org-cite-something) the "oc-something.el" library, in addition to possibly many other tools, registers a "citation processor", for example `something'. That processor may operate on any of the three entry points "activate", "follow", or "export". If you are not sure about which one it supports, you may inspect the processor with, e.g., (org-cite-processor-has-capability-p 'something 'follow) If this is non-nil, you can set `org-cite-follow-processor' to `something'. Once done, calling `org-open-at-point' on a citation starts whatever action the processor defined. If the variable is nil, nothing happens. If you need to use a different processor for a given document, consider using file local variables. Likewise, you can fontify citations according to a given processor using `org-cite-activate-processor'. This time, however, Org provides some fontification even when the variable is nil. The default set-up merely applies new `org-cite' and `org-cite-key' faces on citations. The "export" capability introduces the concept of "style", which is an _indication_ to the citation processor, which may or may consider applying. More precisely, a style can be set for citations and bibliography, at three levels from the most general to the most specific: (setq org-cite-export-processor '(something "bibstyle" "citestyle")) #+cite_export: something bibstyle citestyle #+print_bibliography: bibstyle [cite/citestyle:...] An export processor is required to support at least one default style for citations and bibliography called the "nil" style. It may support any number of other styles, and should treat any unknown style indication as the "nil" style. So [cite/totallyunknownstyle:...] may be treated as [cite/nil: ...] which, in turn, is strictly equivalent to [cite: ...] Now onto the developer point of view. A citation back-end can provide many tools, but in order to interact with Org through the three entry points listed earlier, it also needs to define a so-called processor, using `org-cite-register-processor' function. For reference, here is its docstring. Mark citation processor NAME as available. NAME is a symbol. BODY is a property list, where the following optional keys can be set: `:activate' Function activating a citation. It is called with a single argument: a citation object extracted from the current buffer. It may add text properties to the buffer. If it is not provided, `org-cite-fontify-default' is used. `:export-bibliography' Function rendering a bibliography. It is called with five arguments: a list of citations, a list of bibliography files, the style, as a string or nil, the export back-end, as a symbol, and the communication channel, as a property list. It is called at each \"print_bibliography\" keyword in the parse tree. It may return a string or nil. When it returns nil, the keyword is ignored. Otherwise, the string it returns replaces the keyword in the export output. `:export-citation' (mandatory for \"export\" capability) Function rendering citations. It is called with four arguments: a citation object, the style, as a string or nil, the export back-end, as a symbol, and the communication channel, as a property list. It is called on each citation object in the parse tree. It may return a string or nil. When it returns nil, the citation is ignored. Otherwise, the string it returns replaces the citation object in the export output. `:export-finalizer' Function called at the end of export process. It must accept five arguments: the output, as a string, a list of citations, a list of bibliography files, a list of bibliography styles requested by various \"print_bibliography\" keywords in the document, as strings or nil, and the export back-end, as a symbol. It must return a string, which will become the final output from the export process, barring subsequent modifications from export filters. `:follow' Function called to follow a citation. It accepts two arguments, the citation or citation reference object at point, and any prefix argument received during interactive call of `org-open-at-point'. The "follow" and "activate" capabilities are relatively simple to implement because both require a single function to operate. On the other hand, "export" capability may require up to three functions. Of those, only the `export-citation' function cannot be omitted. The "oc.el" library provides several tools to help developers writing those functions. For example, `org-cite-list-bibliography-files' may be useful when providing "follow" or "activate" capability. Likewise, `org-cite-get-references' lists all citation-reference objects contained in a citation. For each object, you can extract boundaries as buffer positions, the key, the prefix and the suffix. This can be very useful for activating a citation reference, e.g., when apply some specific key-map on a part of the buffer. Most important helper functions available for export are `org-cite-list-citations', which provides the _ordered_ list of citations in the exported document, and `org-cite-inside-footnote-p', which returns the closest (inline) footnote reference or footnote definition containing a citation, if any. This function can be paired, e.g., with `org-export-get-footnote-number'. === Demo time === Let's say I want to implement "oc-demo.el", which will provide "activate" and "export" capabilities. For activation, I want: - the same default fontification (`org-cite' and `org-cite-key' faces), - to display the cite key when mouse is over a citation reference, - hide the unsightly "cite:" part of the citation. I therefore write the following function: (defun org-cite-demo-activate (citation) ;; Apply default fontification, the lazy way. (org-cite-fontify-default citation) ;; Hide "cite:" prefix. (let* ((prefix-start (1+ (org-element-property :begin citation))) (prefix-end (+ 5 prefix-start))) (add-text-properties prefix-start prefix-end '(invisible t)) (org-rear-nonsticky-at prefix-start) (org-rear-nonsticky-at prefix-end)) ;; Apply `help-echo' on each key reference. (org-with-point-at (org-element-property :contents-begin citation) (let ((end (org-element-property :contents-end citation))) (while (re-search-forward org-element-citation-key-re end t) (add-text-properties (match-beginning 0) (match-end 0) ;; Drop the @ symbol. (list 'help-echo (substring (match-string-no-properties 0) 1))))))) I want to export citations as (Doe, 1999) or (1999) when suppress author parameter is set. I also want to support the "plain" style, which removes the parenthesis. The bibliography should be inserted at the very end of the document, listing all bibliography files used, but only if there is some citation and some "print_bibliography" keyword in the document. I won't use :export-bibliography, because it is called at each "print_bibliography" keyword, so possibly in the middle of the document. I'll use a finalizer instead. (defun org-cite-demo-export-citation (citation style back-end info) (concat ;; Global prefix, if any. We use `org-export-data' as prefixes or ;; suffixes may contain special characters that need to be escaped ;; by the export process. (org-export-data (org-element-property :prefix citation) info) (and (not (equal style "plain")) "(") (mapconcat (lambda (ref) (concat (org-export-data (org-element-property :prefix ref) info) (if (org-element-property :suppress-author ref) "1999" "Doe, 1999") (org-export-data (org-element-property :suffix ref) info))) ;; Grab all references within the citation. (org-cite-get-references citation) ", ") (and (not (equal style "plain")) ")") ;; Global suffix, if any. (org-export-data (org-element-property :suffix citation) info))) (defun org-cite-demo-finalizer (output citations bibliography styles backend) (concat output ;; Print bibliography only if there are some citations and ;; a "print_bibliography" keyword in the document. (and citations styles ;proof of "print_bibliography" (concat "\nBibliography: " (mapconcat #'identity bibliography ", ") ".")))) All is left to do is to register the "demo" processor. (org-cite-register-processor 'demo :activate #'org-cite-demo-activate :export-citation #'org-cite-demo-export-citation :export-finalizer #'org-cite-demo-finalizer) That's about it. You can, if you wish so, try out this demo on the following document: --8<---------------cut here---------------start------------->8--- #+cite_export: demo #+bibliography: bib.bib #+bibliography: bib2.bib Simple reference: [cite:@key] Multiple references: [cite:@key1;@key2] Suppress author: [cite:-@key] Plain style: [cite/plain:@key] Full syntax: [cite:common prefix ;prefix @key suffix ;@key2; common suffix] #+print_bibliography: # Local Variables: # org-cite-activate-processor: demo # End: --8<---------------cut here---------------end--------------->8--- WDYT? Regards, -- Nicolas Goaziou
next reply other threads:[~2021-04-21 23:34 UTC|newest] Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-04-21 23:34 Nicolas Goaziou [this message] 2021-04-22 0:15 ` Bruce D'Arcus 2021-04-22 0:35 ` Nicolas Goaziou 2021-04-22 0:56 ` Bruce D'Arcus 2021-04-22 12:02 ` Bruce D'Arcus 2021-04-22 13:14 ` Nicolas Goaziou 2021-04-22 13:23 ` Bruce D'Arcus 2021-04-22 17:47 ` M. ‘quintus’ Gülker 2021-04-22 20:44 ` Bruce D'Arcus 2021-04-24 7:53 ` Nicolas Goaziou 2021-04-24 0:07 ` Bruce D'Arcus 2021-04-24 7:53 ` Nicolas Goaziou 2021-04-24 11:40 ` Bruce D'Arcus 2021-04-25 21:19 ` Denis Maier 2021-04-26 18:36 ` Bruce D'Arcus 2021-04-26 20:02 ` Nicolas Goaziou 2021-04-26 20:13 ` Denis Maier 2021-04-26 20:14 ` Denis Maier 2021-04-26 20:33 ` Nicolas Goaziou 2021-04-26 20:38 ` Denis Maier 2021-04-26 21:11 ` Nicolas Goaziou 2021-04-26 21:52 ` Denis Maier 2021-04-26 21:15 ` Joost Kremers 2021-04-27 12:21 ` Bruce D'Arcus
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