%% 
%%  Ein Beispiel der DANTE-Edition
%%  
%%  2. Auflage
%% 
%%  Beispiel 17-05-16 auf Seite 852.
%% 
%%  Copyright (C) 2016 Herbert Voss
%% 
%%  It may be distributed and/or modified under the conditions
%%  of the LaTeX Project Public License, either version 1.3
%%  of this license or (at your option) any later version.
%% 
%%  See http://www.latex-project.org/lppl.txt for details.
%% 
%% 
%% ==== 
% Show page(s) 1
%% 
%% 
\documentclass[]{exaarticle}
\pagestyle{empty}
\setlength\textwidth{145.16928pt}
\setlength\parindent{0pt}
\usepackage[T1]{fontenc}
\usepackage[scaled=0.82]{beramono}
\usepackage[utf8]{inputenc}
%StartShownPreambleCommands
\usepackage{xparse}
\DeclareDocumentCommand\ZapSpace
  { >{\TrimSpaces} m }{#1}
%StopShownPreambleCommands
\begin{document}
\verb|[   foo    ]|\\\relax
      [   foo    ]\\\relax
      [\ZapSpace{   foo    }]
\end{document}
