Slashed partial derivative sign with blackboard bold

Question

The last time I asked about blackboard bold greek letters and the answers given opened up to me a new world of possibilities. So I'm just having fun with \mathb command (that is exactly the \mathbb defined in the main answer, just renamed that way to still be able to use the original \mathbb), using it with every sign that should represent a matrix; for example I'm using $\slashed{\mathb{p}}$ instead of the usual $\slashed{p}$ in the Dirac slashed notation (here a question about the way to write the slash)

But I have a problem: now I want to write $\slashed{\mathb{\partial}}$ but this error message appears

! Missing \endcsname inserted.
<to be read again> \partial 
l.20142 $\slashed{\mathb{\partial}}$

What can I do? Thanks!

Answer 1

Here is a manual way to do it...save the intermediate result in a box and apply \slashed to the box. The trick now is to redefine \mathb to have this way, perhaps, as the default.

\documentclass{article}
\usepackage{xcolor,slashed}
\input pdf-trans
\newbox\qbox
\def\usecolor#1{\csname\string\color@#1\endcsname\space}
\newcommand\bordercolor[1]{\colsplit{1}{#1}}
\newcommand\fillcolor[1]{\colsplit{0}{#1}}
\newcommand\outline[1]{\leavevmode%
  \def\maltext{#1}%
  \setbox\qbox=\hbox{\maltext}%
  \boxgs{Q q 2 Tr \bbthickness\space w \fillcol\space \bordercol\space}{}%
  \copy\qbox%
}
\newcommand\mathb[1]{\outline{$#1$}}
\newcommand\textbb[1]{\outline{#1}}
\newcommand\colsplit[2]{\colorlet{tmpcolor}{#2}\edef\tmp{\usecolor{tmpcolor}}%
  \def\tmpB{}\expandafter\colsplithelp\tmp\relax%
  \ifnum0=#1\relax\edef\fillcol{\tmpB}\else\edef\bordercol{\tmpC}\fi}
\def\colsplithelp#1#2 #3\relax{%
  \edef\tmpB{\tmpB#1#2 }%
  \ifnum `#1>`9\relax\def\tmpC{#3}\else\colsplithelp#3\relax\fi
}
\bordercolor{black}
\fillcolor{white}
\newcommand\bbthickness{.15}
\begin{document}
$\sbox0{$\mathb{\partial}$} \slashed{\copy0}$
\end{document}