I'm trying to have 2 separate "citation style" in my document, leveraging the customX existing document type (an extension would be to have a separate document type, but I don't want to play with the lbx file for the moment).
So I've used the type customc for my test. In the customc citation, there are no author and the citation should be "title, postnote" with an optional citation mode being "{title} {note}, postnote" if the note field is defined.
I'm having difficulties redefining the "customc:cite" for the document type customc. I thought it would be simply the same as DeclareBibliographyDriver bu I cannot find a way to make them work. How could I achieve this ? Here is what I get so far
And here is my MWE :
\documentclass[11pt]{memoir}
\usepackage{filecontents}
\begin{filecontents}{test.bib}
@book{book1,
author = {Author, Roberto B.},
title = {The Writing of History in Ancient Egypt during the First Millennium BC (ca. 1070-180 BC). Trends and Perspectives},
shorttitle = {A short title},
}
@customc{atf1,
title = {A title},
note = {= Un titre},
}
@customc{atf2,
title = {Another title},
}
\end{filecontents}
\usepackage[style=authortitle,backend=biber,language=french]{biblatex}
\addbibresource{test.bib}
\UndefineBibliographyExtras{french}{\restorecommand\mkbibnamefamily}
\newcommand{\no}{n\textsuperscript{o}\addnbthinspace}
\newcommand{\nos}{n\textsuperscript{os}\addnbthinspace}
\newcommand{\considerant}{consid.\addnbthinspace}
\renewcommand*{\mkbibnamefamily}{\textsc}
\renewcommand*{\revsdnamepunct}{}
\DeclareFieldFormat*{citetitle}{\mkbibemph{#1}}
\renewcommand*{\multicitedelim}{\addsemicolon\space}
\newcommand{\ucites}{\parencites}
\DeclareFieldFormat[customc]{title}{#1}
\DeclareFieldFormat[customc]{citetitle}{#1}
\DeclareFieldFormat[customc]{note}{#1}
\DeclareFieldFormat[customc]{postnote}{\considerant #1}
\DeclareBibliographyDriver{customc}{%
\usebibmacro{bibindex}%
\usebibmacro{begentry}%
\printfield{title}%
\newunit\newblock
\printfield{note}%
\usebibmacro{finentry}
}
\newbibmacro*{customc:cite}{%
\usebibmacro{cite:title}%
\iffieldundef{note}{}{\printfield{note}}%
}
\begin{document}
a first test as demo \ucites[1]{book1}. a second text which also has some references \ucites[\nos 1, 2, 5]{book1}.
Finally a test using the custom citation style \ucites[2.a \& 2.b]{atf1}[5.1]{atf2}. However the display should be "A title = Un titre, consid. 2.a \& 2.b".
\end{document}

citebibmacro. I could write an answer how that would work in the MWE, but I have the feeling that you may already have a highly modifiedcitebibmacro, in that case it might help if you added its definition to the MWE. In its current formcustomc:citewon't do anything. – moewe Oct 29 '18 at 09:29authortitlethings should be not that horrible. – moewe Oct 29 '18 at 09:43