Eating a dot after a command

Question

I have a bibliography in which URLs are printed with a following "." I would like to omit the URLs to save space and I could do this by redefining the URL command, but this would leave me with a dot. Is there a way to define a command that eats a following "."?

Answer 1

• The redefinition of \url is not trivial, because the argument might contain the percent character. Therefore the argument needs to be read with verbatim catcodes.

• The dot can be removed using \@ifnextchar.\@gobble{}. This also catches the case that \url{...} is not followed by a dot. As side effect \@ifnextchar removes spaces. This can be avoided by using \ltx@ifnextchar@nospace of package ltxcmds instead of \@ifnextchar.

Example file:

\documentclass{article}
\usepackage{url}
\makeatletter
\newcommand*{\urlgobble}{%
  \begingroup
    % set verbatim catcodes
    \let\do\@makeother
    \dospecials
    % restore catcode of argument braces
    \catcode`\{=1 %
    \catcode`\}=2 %
    \@urlgobble
}
\newcommand*{\@urlgobble}[1]{%
  % eats the URL in #1
  \endgroup
  % skip an optional dot
  \@ifnextchar.\@gobble{}%
}
\newcommand*{\skipurls}{\let\url\urlgobble}
\makeatother

\begin{document}
Normal url:
  \url{http://www.example.org/Hello%20World.html}

\skipurls
Skipped urls:
  \url{http://www.example.net/Hello%20World.html}
  \url{http://www.example.com/Hello%20World.html}.
\end{document}

Answer 2

Works only if the URL has no special characters!

\documentclass{article}
\usepackage{url}
\begin{document}

\url{http://www.dante.de}.

\makeatletter
\let\URL\url
\def\url#1{\@ifnextchar.\url@i{\url@i.}}
\def\url@i.{}
\makeatother

Not printed: \url{http://www.dante.de}.

\URL{http://www.dante.de}

\end{document}