In theorem style, how to make the dot font depend on the name font ?

Question

I have to use the thmtools package to style my theorems, lemmas, remarks etc.

Unfortunately, I noticed that when I give an optional name to a remark for instance this name is in normal font, but the dot after it is in bold and it stands out as not nice IMPO!

I want to keep in bold font the name remark and the dot when there is no optional name but I want the dot in normal font when there is one optional name. How do I do it?

Here is my MWE:

\documentclass{amsbook}

\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{thmtools}

\declaretheoremstyle[spaceabove=6pt plus 0pt minus 2pt, spacebelow=0pt plus 0pt minus 2pt, headfont=\bfseries, bodyfont=\normalfont, postheadspace=5pt plus 1pt minus 1pt]{myremstyle}

\declaretheorem[style=myremstyle,name=Remarque,numbered=no]{rem}

\begin{document}
\begin{rem}[not quite nice effect]
\end{rem}
\end{document}

Answer 1

For reasons I don't understand, the note is typeset in a group. Anyway, the workaround is not pretty, because you need to specify headformat in all styles you define.

\documentclass{amsbook}

\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{thmtools}
\usepackage{etoolbox}

\makeatletter
% don't typeset the note in a group, so the punctuation inherits
% the font specification of the note
\patchcmd{\thmt@setheadstyle}
 {\bgroup\thmt@space}
 {\thmt@space}
 {}{}
\patchcmd{\thmt@setheadstyle}
 {\egroup\fi}
 {\fi}
 {}{}
\makeatother

\declaretheoremstyle[
  spaceabove=6pt plus 0pt minus 2pt,
  spacebelow=0pt plus 0pt minus 2pt,
  headfont=\bfseries,
  bodyfont=\normalfont,
  postheadspace=5pt plus 1pt minus 1pt,
  headformat=\NAME\NOTE,
]{myremstyle}

\declaretheoremstyle[
  spaceabove=6pt plus 0pt minus 2pt,
  spacebelow=0pt plus 0pt minus 2pt,
  headfont=\bfseries,
  bodyfont=\normalfont,
  postheadspace=5pt plus 1pt minus 1pt,
  headformat=\NAME\ \NUMBER\NOTE,
]{myfoostyle}

\declaretheorem[
  style=myremstyle,
  name=Remarque,
  numbered=no
]{rem}

\declaretheorem[
  style=myfoostyle,
  name=Foo,
]{foo}

\begin{document}

\begin{rem}[nice effect]
Some remark
\end{rem}
\begin{rem}
Some remark
\end{rem}
\begin{foo}[nice effect]
Some foo
\end{foo}
\begin{foo}
Some foo
\end{foo}
\end{document}

Answer 2

You can use headformat with \NAME, \NUMBER, \NOTE, and apply \normalfont if there is annotation:

\documentclass{amsbook}

\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{thmtools}

\declaretheoremstyle[
  spaceabove=6pt plus 0pt minus 2pt, 
  spacebelow=0pt plus 0pt minus 2pt, 
  headfont=\bfseries, 
  bodyfont=\normalfont,
  postheadspace=5pt plus 1pt minus 1pt,
  headformat={\NAME~\NUMBER\NOTE\if\empty\relax\else\normalfont\fi}
]{myremstyle}
\declaretheorem[style=myremstyle,name=Remarque,numbered=no]{rem}

\begin{document}
\begin{rem}[quite nice effect]
test text.
\end{rem}
\begin{rem}
test text.
\end{rem}
\end{document}

The result: