% Licensed to the Apache Software Foundation (ASF) under one or more
% contributor license agreements. See the NOTICE file distributed with
% this work for additional information regarding copyright ownership.
% The ASF licenses this file to You under the Apache License, Version 2.0
% (the "License"); you may not use this file except in compliance with
% the License. You may obtain a copy of the License at
% Unless required by applicable law or agreed to in writing, software
% distributed under the License is distributed on an "AS IS" BASIS,
% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
% See the License for the specific language governing permissions and
% limitations under the License.
% \BeforeBegin{environment}{code-to-execute}
% \BeforeEnd {environment}{code-to-execute}
% \AfterBegin {environment}{code-to-execute}
% \AfterEnd {environment}{code-to-execute}
% Save \begin and \end to \BeginEnvironment and \EndEnvironment
\let\BeginEnvironment=\begin
\def\IfUnDef#1{\expandafter\ifx\csname#1\endcsname\relax}
% Null command needed to for \nothing{something}=.nothing.
% if defined \BeforeBeg for this environment, execute it
\IfUnDef{BeforeBeg#1}\else\csname BeforeBeg#1\endcsname\fi%
\IfUnDef{AfterBeg#1}% This is done to skip the command for environments
% which can take arguments, like multicols; YOU MUST NOT
% USE \AfterBegin{...}{...} for such environments!
\let\SaveBegEng=\BeginEnvironment%
% and execute code after \begin{environment}
\csname AfterBeg#1\endcsname%
\let\SaveBegEng=\NullCom%
% execute code before \end{environment}
\IfUnDef{BeforeEnd#1}\else\csname BeforeEnd#1\endcsname\fi%
% and execute code after \begin{environment}
\IfUnDef{AfterEnd#1}\else\csname AfterEnd#1\endcsname\fi%
% \BeforeBegin{environment}{code-to-execute}
% \BeforeEnd {environment}{code-to-execute}
% \AfterBegin {environment}{code-to-execute}
% \AfterEnd {environment}{code-to-execute}
\def\BeforeBegin#1#2{\expandafter\gdef\csname BeforeBeg#1\endcsname
\def\BeforeEnd #1#2{\expandafter\gdef\csname BeforeEnd#1\endcsname
\def\AfterBegin #1#2{\expandafter\gdef\csname AfterBeg#1\endcsname {#2}}
\def\AfterEnd #1#2{\expandafter\gdef\csname AfterEnd#1\endcsname{#2}}
