Parentheses in citations with biblatex-apa

[sorsted]

According to the biblatex-apa documentation (section 4.1), APA dictates that citations inside parentheses should not contain extra parentheses. Therefore, it provides the command

\nptextcite[⟨prenote⟩][⟨postnote⟩]{⟨key⟩}⟨punctuation⟩

which works like \textcite, but suppresses the parentheses.

Is there a way to get this behaviour to be supported with the markdown package, so that the following will render correctly? I am willing to use LuaTeX if that helps.

\documentclass{article}

\usepackage[american]{babel}
\usepackage{csquotes}
\usepackage[style=apa]{biblatex}

\usepackage[citations]{markdown}

\begin{document}

\begin{markdown}

Here is a reference with parentheses: @someauthor [p. 233].

(Here is a reference without parentheses: @someauthor [p. 233].)

\end{markdown}

\printbibliography

\end{document}

EDIT: I know that I can do [Here is a reference without parentheses: @someauthor, p. 233], but this will not work for more complicated examples. For instance, I cannot do (This follows from @someauthor and also from @someotherauthor.) this way. The only thing I can currently do is [This follows from @someauthor; and also from @someotherauthor.], which inserts an unwanted semicolon in the output.

EDIT: Note that it is probably best if parenthesis levels are counted for each paragraph rather than each line, so that the following works:

(This is another reference to
@someauthor,
p. 233)

It is probably also best if the parenthesis level counter is reset for every new paragraph so that a forgotten ) doesn’t screw up the rest of the document.

EDIT: It is probably also best if this can be solved in a way that doesn’t break existing LaTeX syntax involving parentheses when this appears in hybrid mode.

[Witiko]

@sorsted This is related to the text citation renderer. The Markdown package provides a default renderer for LaTeX, which tries to cover a couple use cases (BibTeX, Natbib, and BibLaTeX), but you need to adopt it to special cases such as biblatex-apa. Here, it should be sufficient to replace the \textcites command with \nptextcites:

\usepackage{xpatch}
\xpatchcmd
  \markdownLaTeXBibLaTeXTextCitations
  {\textcites}%
  {\nptextcites}%
  {}%
  {}

Please note that default renderers are subject to change, so if you want to be sure that your code does not break in the long run (e.g. we might get rid of the \markdownLaTeXBibLaTeXTextCitations command in the future), you should copy the renderer definition from the Markdown package to your document/style file and do your changes there.

[Witiko]

That should work. However, if you want to harden your document against possible changes in default renderers, you should also copy the definition of \markdownLaTeXCitationsCounter and the \markdownSetup{rendererPrototypes={cite={...}, textCite={...}}}. This will ensure that you don't depend on the default renderers if they should change.

[Witiko]

The citation renderers haven't changed in a couple years, but it is good practice.

[sorsted]

Okay, I will do that.

But this got me thinking again: Suppose that I make this redefinition. Then automating this process would amount to the following: When markdown wants to interpret the markdown syntax of some piece of text, run some regex replacement on it that replaces @ inside a balanced pair of parentheses by -@. And only then run the markdown interpreter. Is this not possible to do with the current version of the markdown package?

I realize that this will break syntax like write me on [this email address](mailto:foo@bar.com), but I think I can live with that.

[Witiko]

You could certainly modify markdown.lua to do that for you in the M.reader object. Alternatively, you could also modify the buffering routine for \begin{markdown} ... \end{markdown} in markdown.tex and use e.g. the l3regex library from LaTeX3 to do what you are after, but this would be more difficult and would not extend to commands such as \markdownInput.

[Witiko]

Here is a first draft of what user syntax extensions might look like: #172. Feedback will be appreciated.

[sorsted]

Update: The good guys at TeX.SX have provided me with the perfect solution which doesn’t even require us to break with the standard markdown citation syntax. Furthermore, this will work even if later we decide to instead use pandoc to convert the markdown document to LaTeX for further post-editing. @Witiko, please tell me if I did everything correctly and have the right amount of \expandafter's. At least it compiles just fine.

% Compile with LuaTeX:
\begin{filecontents*}{find_parens.lua}
-- From Marcel Krüger's answer at https://tex.stackexchange.com/a/654261/80496

-- How to translate boolean results to TeX macros selecting the right arguments
local bool_to_token = {[false] = token.create'use_ii:nn', [true] = token.create'use_i:nn'}

-- The codepoints we have to look for
local left_paren = string.byte'('
local right_paren = string.byte')'

-- Some boilerplate to define an unexpandable command sequence from Lua
local id = luatexbase.new_luafunction'ifInParensTF'
token.set_lua('ifInParensTF', id, 'protected')
lua.get_functions_table()[id] = function()

  -- We want to look at the current list
  local head = tex.nest.top.head

  local level = 0
  -- and look at all unprocessed characters
  for _, char in node.traverse_char(head) do
    -- Track the nesting level
    if char == left_paren then
      level = level + 1
    elseif char == right_paren then
      if level > 0 then
        level = level - 1
      else
        -- Negative levels don't make sense, so we ignore the ) instead. Print a warning though to avoid surprises.
        texio.write_nl'WARNING: Unable to reliably determine if inside parentheses since the paragraphs contains an unmatched right parentheses.'
        texio.write_nl'The unmatched parentheses will be ignored.'
      end
    end
  end
  -- Finally insert a macro which will select the first or second argument dependingon whether level > 0
  token.put_next(bool_to_token[level > 0])
end
\end{filecontents*}
\begin{filecontents*}{ref.bib}

@online{texSX,
    author={{egreg et al.}},
    year={2022},
    title={{TeX Stack Exchange}},
    url={https://tex.stackexchange.com/},
}

\end{filecontents*}

\documentclass{article}

\usepackage[american]{babel}
\usepackage{csquotes}
\usepackage[style=apa]{biblatex}

\directlua{require'find_parens'}

\addbibresource{ref.bib}

\usepackage[citations]{markdown}

\NewDocumentCommand \autotextcites {}{%
  \ifInParensTF {%
    \nptextcites
  }{%
    \textcites
  }%
}

\NewDocumentCommand \autoparencites {}{%
  \ifInParensTF {%
    \nptextcites
  }{%
    \parencites
  }%
}

\makeatletter

\let\markdownLaTeXCitationsCounter=\relax
\newcount\markdownLaTeXCitationsCounter

\def\markdownLaTeXBibLaTeXAPACitations#1#2#3#4#5{%
  \advance\markdownLaTeXCitationsCounter by 1\relax
  \ifnum\markdownLaTeXCitationsCounter>\markdownLaTeXCitationsTotal\relax
    \autoparencites#1[#3][#4]{#5}%
    \expandafter\@gobbletwo
  \fi\markdownLaTeXBibLaTeXAPACitations{#1[#3][#4]{#5}}}
\def\markdownLaTeXBibLaTeXAPATextCitations#1#2#3#4#5{%
  \advance\markdownLaTeXCitationsCounter by 1\relax
  \ifnum\markdownLaTeXCitationsCounter>\markdownLaTeXCitationsTotal\relax
    \autotextcites#1[#3][#4]{#5}%
    \expandafter\@gobbletwo
  \fi\markdownLaTeXBibLaTeXAPATextCitations{#1[#3][#4]{#5}}}

\markdownSetup{rendererPrototypes = {
	cite = {%
		\markdownLaTeXCitationsCounter=1%
		\def\markdownLaTeXCitationsTotal{#1}%
		\expandafter\markdownLaTeXBibLaTeXAPACitations
		\expandafter{\expandafter}%
	},
	textCite = {%
		\markdownLaTeXCitationsCounter=1%
		\def\markdownLaTeXCitationsTotal{#1}%
		\expandafter\markdownLaTeXBibLaTeXAPATextCitations
		\expandafter{\expandafter}%
	}%
}}

\makeatother


\begin{document}

\begin{markdown}

This follows from @texSX.

(It also follows from @texSX.)

(It also follows from [@texSX].)

(It also follows from
@texSX
among other places.)

(It also follows from other resources. Notice that we forgot a closing parenthesis.

But @texSX is a good start.

\end{markdown}

\printbibliography

\end{document}

[Witiko]

Nice solution. Mind that your code still assumes that \markdownLaTeXCitationsCounter exists, which it may not in the future. You should have \let\markdownLaTeXCitationsCounter=\relax followed by \newcount\markdownLaTeXCitationsCounter in your code.

[sorsted]

Like this?

[sorsted]

I noticed that the manual uses renderers = rather than rendererPrototypes =. Which is more correct here?