spamsthm.sty

%% Generic LNCS-style theorems also without LNCS.
%%
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{spamsthm}

\let\if@sp@envcntsect\iffalse
\let\if@sp@envcntsame\iffalse
\let\if@sp@envcntswap\iffalse
\DeclareOption{envcountsect}{\let\if@sp@envcntsect\iftrue}
\DeclareOption{envcountsame}{\let\if@sp@envcntsame\iftrue}
\DeclareOption{envcountswap}{\let\if@sp@envcntswap\iftrue}
\ProcessOptions

\ifx\spnewtheorem\undefined

%% NON-LLNCS SETUP.

\RequirePackage{amsthm}

\def\th@major{\thm@notefont{\bf}\itshape}
\def\th@normal{\thm@notefont{\bf}\normalfont}
\def\th@minor{\thm@headfont{\it}\thm@notefont{\it}\normalfont
  \thm@preskip\topsep \divide\thm@preskip\tw@ \thm@postskip\thm@preskip}

\let\theorem=\undefined
\let\lemma=\undefined
\let\definition=\undefined
\let\example=\undefined
\let\proposition=\undefined
\let\note=\undefined

\theoremstyle{major}
\if@sp@envcntswap
 \swapnumbers
\fi
\if@sp@envcntsect
 \newtheorem{theorem}{Theorem}[section]
\else
 \newtheorem{theorem}{Theorem}
\fi
\if@sp@envcntsame
  \def\spamsnewtheorem#1#2{\newtheorem{#1}[theorem]{#2}}
\else\if@sp@envcntsect
  \def\spamsnewtheorem#1#2{\newtheorem{#1}{#2}[section]}
\else
  \def\spamsnewtheorem#1#2{\newtheorem{#1}{#2}}
\fi\fi

\spamsnewtheorem{lemma}{Lemma}
\spamsnewtheorem{corollary}{Corollary}
\spamsnewtheorem{conjecture}{Conjecture}

\theoremstyle{normal}
\spamsnewtheorem{definition}{Definition}
\spamsnewtheorem{example}{Example}
\spamsnewtheorem{scenario}{Scenario}
\spamsnewtheorem{proposition}{Proposition}
\spamsnewtheorem{property}{Property}
\spamsnewtheorem{notation}{Notation}
\spamsnewtheorem{exercise}{Exercise}
\spamsnewtheorem{problem}{Problem}
\spamsnewtheorem{question}{Question}
\spamsnewtheorem{solution}{Solution}

\theoremstyle{minor}
\spamsnewtheorem{remark}{Remark}
\spamsnewtheorem{note}{Note}
\spamsnewtheorem{case}{Case}

\theoremstyle{normal}

\newenvironment{one-off}[2][normal]{\theoremstyle{#1}\spamsnewtheorem{one-off@#2}{#2}\def\end@one@off{\csname endone-off@#2\endcsname}\csname one-off@#2\endcsname}{\end@one@off}

\else

%% LLNCS TWEAKS

%% Put number before theorems :)
\if@sp@envcntswap
\def\@spbegintheorem#1#2#3#4{\trivlist
                 \item[\hskip\labelsep{#3#2\ #1\@thmcounterend}]#4}
\def\@spopargbegintheorem#1#2#3#4#5{\trivlist
      \item[\hskip\labelsep{#4#2\ #1}]{#4(#3)\@thmcounterend\ }#5}
\fi

\if@sp@envcntsame
  \def\spamsnewtheorem#1#2{\spnewtheorem{#1}{#2}{\bfseries}{\rmfamily}}
\else\if@sp@envcntsect
  \def\spamsnewtheorem#1#2{\spnewtheorem{#1}{#2}{\bfseries}{\rmfamily}}
\else
  \def\spamsnewtheorem#1#2{\spnewtheorem{#1}{#2}{\bfseries}{\rmfamily}}
\fi\fi

\newenvironment{one-off}[2][normal]{\spnewtheorem{one-off@#2}[theorem]{#2}{\itshape}{\rmfamily}\def\end@one@off{\csname endone-off@#2\endcsname}\csname one-off@#2\endcsname}{\end@one@off}

\fi