An easier way for capitalizing prenote in citations with biblatex?

Question

In this post I got the advise to use \autocap{s}ee within a citation, e.g. \autocite[\autocap{s}ee][5][ref] to get context sensitive capitalizing of the letter ‘s’. So if I switch from inline citation to footnote citation the word ‘see’ would be written as ‘See’.

But it is a bit cumbersome to write \autocap in all references. Is there a way to integrate this command into for example the \usebibmacro{pre note} or to create a new bibmacro like e.g. prenotecap? Then I would define:

\DeclareCiteCommand{\parencite}[\mkbibparens]
    {\usebibmacro{prenotecap}}
    {\usebibmacro{citeindex}%
        \printtext[brackets]{\usebibmacro{cite} \usebibmacro{postnote}}}
    {\multicitedelim}
    {}

and I’m done.

Would be nice if someone has a hint how to manage the \newbibmacro, because I don’t get the explanation in the biblatex user guide.

Edit: So here is a MWE, which should make it clear what I want to achieve. The word 'see' should be printed as 'See' if I use autocite=footnote and 'see' if I use autocite=inline. But I don't want to use \autocap for each reference.

\documentclass{article}
\usepackage[style=alphabetic, autocite=footnote]{biblatex}

\DeclareCiteCommand{\footcite}[\mkbibfootnote]
    {\usebibmacro{prenote}}
    {\usebibmacro{citeindex}%
        \printtext[brackets]{\usebibmacro{cite} \usebibmacro{postnote}}}
    {\multicitedelim}
    {}  

\DeclareMultiCiteCommand{\footcites}[\mkbibfootnote]%
    {\footcite}{\multicitedelim}

\DeclareAutoCiteCommand{footnote}[l]{\footcite}{\footcites}

\begin{filecontents*}{bibliography.bib}
@BOOK{Cornelisse1979,
  author = {Cornelisse, J. W. and Schöyer, H. Ferry R. and Wakker, Karel F.},
  title = {Rocket Propulsion and Spaceflight Dynamics},
  year = {1979},
  publisher = {Pitman},
}
\end{filecontents*}

\bibliography{bibliography.bib}

\begin{document}
\null
\vfill

How the citation look like: \autocite[see][35]{Cornelisse1979}
How it should look like: \autocite[\autocap{s}ee][35]{Cornelisse1979}
\end{document}

Answer 1

The biblatex package defines the \MakeSentenceCase macro that takes care of the capitalization for you, you just have to tell the bibmacro to use it. I start by defining a field format that uses \MakeSentenceCase and then patch the bibmacro to use the field format with the prenote field. I use the xpatch package to do this, but there are lots of ways to patch macros. You just need to add the following code to your preamble when you use autocite=footnote.

\DeclareFieldFormat{sentencecase}{\MakeSentenceCase{#1}}
\usepackage{xpatch}
\xpatchbibmacro{prenote}{\printfield{prenote}}{\printfield[sentencecase]{prenote}}{}{}

You will have to remove the code when you use autocite=inline. There is probably a way of automatically doing this depending on the value of autocite, but I cannot figure out how the option is used.

A full MWE:

\documentclass{article}
\usepackage[style=alphabetic, autocite=footnote]{biblatex}

\DeclareCiteCommand{\footcite}[\mkbibfootnote]
    {\usebibmacro{prenote}}
    {\usebibmacro{citeindex}%
        \printtext[brackets]{\usebibmacro{cite} \usebibmacro{postnote}}}
    {\multicitedelim}
    {}  

\DeclareFieldFormat{sentencecase}{\MakeSentenceCase{#1}}
\usepackage{xpatch}
\xpatchbibmacro{prenote}{\printfield{prenote}}{\printfield[sentencecase]{prenote}}{}{}


\DeclareMultiCiteCommand{\footcites}[\mkbibfootnote]%
    {\footcite}{\multicitedelim}

\DeclareAutoCiteCommand{footnote}[l]{\footcite}{\footcites}

\begin{filecontents*}{bibliography.bib}
@BOOK{Cornelisse1979,
  author = {Cornelisse, J. W. and Schöyer, H. Ferry R. and Wakker, Karel F.},
  title = {Rocket Propulsion and Spaceflight Dynamics},
  year = {1979},
  publisher = {Pitman},
}
\end{filecontents*}

\bibliography{bibliography.bib}

\begin{document}

\null
\vfill

How the citation look like: \autocite[see][35]{Cornelisse1979}
How it should look like: \autocite[\autocap{s}ee][35]{Cornelisse1979}
\end{document}