# Punctuation after title and Beamer

I'm trying to customize the bibliography for a presentation. I'm running into trouble with the punctuation after the title. As a MWE, I wrote the following `biblatex.cfg` file:

``````\ExecuteBibliographyOptions{giveninits=true, uniquename=false}

\DeclareBibliographyDriver{book}{%
\usebibmacro{bibindex}%
\usebibmacro{begentry}%
\usebibmacro{author}%
\setunit{\labelnamepunct}%
\usebibmacro{title}%
\usebibmacro{publisher+location+date}%
\printfield{note}%
\usebibmacro{finentry}}

\newbibmacro*{volume+chapter+pages}{%
\printfield{volume}%
\newunit%
\printfield{chapter}%
\setunit{\bibpagespunct}%
\printfield{pages}}
``````

There should be a period after the title. However, Beamer inserts a comma. Other classes (e.g., `scrartcl`) do insert a period after the title. Beamer correctly inserts a period between the publisher and the note though.

I tried modifying the bibmacro `title`, removing all instances of `\newunit`, to no avail.

Does anyone know what's going on?

This has to do with how `beamer` patches some of `biblatex`'s macros to include the colouring.

In `beamerbaselocalstructure.sty` we find

``````\AtBeginDocument{%
{%[...]
\apptocmd{\abx@macro@title}
{\ifcsundef{abx@field@title}{}{\midsentence\newunitpunct}%
\newblock\usebeamercolor[fg]{bibliography entry note}}{}{}}
{}}
``````

This shows that the `title` macro is changed to always print a `\newunitpunct` after the title (not even in a `\setunit`, the punctuation is printed immediately).

You can fix this by resetting the `title` macro in `\AtBeginDocument` to its original form from `biblatex.def` and adding the colouring macros.

``````\AtBeginDocument{%
\renewbibmacro*{title}{%
\usebeamercolor[fg]{bibliography entry title}%
\ifboolexpr{
test {\iffieldundef{title}}
and
test {\iffieldundef{subtitle}}
}
{}
{\printtext[title]{%
\printfield[titlecase]{title}%
\setunit{\subtitlepunct}%
\printfield[titlecase]{subtitle}}%
\newunit}%