# How to inspect current values of parameters of theorem style?

I'd like to alter the plain theorem style so it uses \slshape instead of \itshape. I know I can define my own style via \newtheoremstyle but I don't know how to inspect (possibly in runtime) the current values of the parameters of the style so I can just change what I need and leave the rest alone.

You can see it in the amsthm.sty file sitting in somewhere in your distro

\thm@style{plain}
\newtoks\thm@bodyfont  \thm@bodyfont{\itshape}
\newtoks\thm@notefont  \thm@notefont{}
\newskip\thm@preskip \newskip\thm@postskip
\def\thm@space@setup{%
\thm@preskip=\topsep \thm@postskip=\thm@preskip
}


This is kind of the bowel movement version of the user-level and much clearer \newtheoremstyle command. I don't recommend fiddling with the already defined styles but if we were doing it from scracth we would have (didn't check though)

\newtheoremstyle{plain}{\topsep}{\topsep}{\itshape}{}{\bfseries}{.}{.5em}{}%

• I would think that inheritance between styles or at least exposing the defaults is standard functionality. What if I later use some package which alters the definitions? Then the hard-coded values of parameters don't make sense. And for your values, somewhere I've seen 5pt plus 1pt minus 1pt and somewhere .5em for space parameter. – user87690 May 10 '14 at 13:03
• @user87690 Most packages (the good ones) always offer a switch for keeping the originals. – percusse May 10 '14 at 13:04

It seems that the easiest way to do it is \def \th@plain {\slshape} or better: \def \th@slanted {\slshape} and then use \theoremstyle{slanted}. There is/was also macro \theorembodyfont which is intended for this, but I'm not sure in what package it is located.