Create own cite command in biblatex

Question

I have the following problem: I need a kind of very simple "double citing system". For normal literature I use the author-year style in biblatex without problems. I made following small changes:

\renewcommand*{\mkbibnamelast}[1]{\textsc{#1}}
\renewcommand{\postnotedelim}{\addcolon\space}
\DeclareFieldFormat{postnote}{#1}

The problem is now I want to cite old books (early modern period) in a different way (not as author-year), something like this:

 Shortauthor, *shorttitle*, p. 124

I think a solution is to write an own cite command, something like this, which seems to work well:

\DeclareBibliographyDriver{myshort}{%
 \usebibmacro{begentry}%
  \ifboolexpr{ test{\ifnameundef{shortauthor}} 
            or test {\iffieldundef{shorttitle}}}
   {\usedriver{}{\thefield{entrytype}}}
   {\printnames{shortauthor}%
    \setunit{\addcomma\space}%
    \printfield{shorttitle}\isdot}%
    \usebibmacro{finentry}%
  }

  \DeclareCiteCommand{\mycite}[\mkbibfootnote]
   {\usebibmacro{prenote}}
   {\usedriver{}{myshort}}
   {\multicitedelim}
    {\usebibmacro{postnote}}

BUT (and this is my actual question): is there a way to:

• disable the small capitals of the author?
• put the title in cursive?
• get the "p." for pages back?

That is, a way of somehow disable for this concrete command the general options I put with the renewcommands, etc.

Answer 1

A useful trick for situations like this is to create a toggle that it is turned on when you enter the command and turned off when leaving the command:

\newtoggle{mycite}

\renewcommand*{\mkbibnamelast}[1]{\iftoggle{mycite}{#1}{\textsc{#1}}}
\renewcommand{\postnotedelim}{\iftoggle{mycite}{\addcomma\addspace}{\addcolon\space}}
\DeclareFieldFormat{postnote}{#1}

and then, when you define your new cite command:

\DeclareCiteCommand{\mycite}[\mkbibfootnote]
   {\toggletrue{mycite}\usebibmacro{prenote}}
   {\usebibmacro{mycite}}
   {\multicitedelim}
   {\usebibmacro{postnote}\togglefalse{mycite}}

By the way, you cannot use \usedriver{}{\thefield{entrytype} within the definition of \DeclareBibliographyDriver: it will enter in an infinite loop and TeX will report an error. What you can do is to define a new bib macro. For example, using your definition as a starting point (and adjusted to put the (short)title in itialic):

\newbibmacro{mycite}{
   \ifboolexpr
     {test {\ifnameundef{shortauthor}} or
      test {\iffieldundef{shorttitle}}}
     {\usedriver{}{\thefield{entrytype}}} 
     {\printnames{shortauthor}%
     \setunit{\addcomma\space}%
     \mkbibemph{\printfield{shorttitle}}}
}