How to align short footnotes (centred) and longer footnotes (left) in one document

Question

I am wondering whether there is some package/code that addresses the following three criteria:

• Shorter footnotes, e.g. Quine (1960, 22), would be sitting centred on the bottom of the page, if (and only if) there is only one footnote on the particular page.

• Once a longer footnote appears on a given page, i.e. one that has more than one line and thus runs by the 'usual' footnote margins, a shorter one, appearing on the same page, would 'adapt' and sit aligned to the 'usual' left margin as well.

• Additionally, in the case of two or even three short footnotes appearing on one page at the same time (either in absence or presence of a longer one), they would 'become' one paragraph. That is, the shorter footnotes would all be in one line but still be centred.

I do not have any MWE here since my question is rather about whether this is possible at all. The handbook and all sources I am aware of do not discuss this issue (or I did not find it, in which case I apologise).

I am reading a couple of recent Oxford University Press books right now, which do have exactly this footnote design, and I am curious if it can be achieved using TeX/LaTeX/XeTeX. I am aware of footmisc, manyfoot, and bigfoot but neither have an obvious statement in the documentation that would resolve the issue. I suppose that manyfoot, for instance, would help with the paragraph style issue, by introducing different levels, but then you have different counters, different ways to call footnotes, which is is complicated or at least non-ideal. I am looking for a more basic solution.

Thank you so much for helping.

Answer 1

This answer tries to address points 1 and 2 of the questioner's inquiry, but not point 3. Additionally, because this answer uses collect, it suffers the drawback of requiring the user to \includecollection after the last footnote on a given page. That, as is, makes the answer of very low value.

However, I am hoping that someone reading this anwer might know of a way to make that \includecollection happen automatically on each page. I tried doing it via a redefinition of \thepage. However, by that point, the page is too far gone to capture the footnotes.

\documentclass{article}
\textheight 1in

\usepackage{collect}
\usepackage{ifthen}
\makeatletter
\let\sv@makefntext\@makefntext
\renewcommand\@makefntext[1]{\footform\sv@makefntext{#1}}
\makeatother

\definecollection{fntext}

\newcounter{startnote}
\setcounter{startnote}{1}
\newcounter{currentpage}
\setcounter{currentpage}{-1}

\newlength\indentlength
\setlength\indentlength{\textwidth}
\addtolength\indentlength{-\parindent}

\newcommand\myfootnote[1]{%
  \ifthenelse{\equal{\value{page}}{\value{currentpage}}}{}{%
    \setcounter{currentpage}{\value{page}}%
    \def\footform{\centering}}%
  \setbox0=\hbox{\footnotesize#1}%
  \ifdim\wd0>\indentlength\gdef\footform{}\fi%
  \footnotemark%
  \begin{collect}{fntext}{\setcounter{footnote}{\thestartnote}\footform}{}
    \stepcounter{startnote}%
    \footnotetext{#1}%
  \end{collect}
}

\begin{document}
This\myfootnote{short} is 
a\myfootnote{Long long long long long long long long long long long long
 long long long long long long long} test\myfootnote{third}.

\includecollection{fntext}

\clearpage

This\myfootnote{short} is a\myfootnote{second} test\myfootnote{third}.

\includecollection{fntext}
\end{document}

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