[Tex/LaTex] Escaping special characters for use as a URL

comma-separated listforeachmacrosurls

If a url contain special characters (~ and #) using it as

\href{http://people.brunel.ac.uk/~mastmmg/ssguide/set_work.html#4_32}{people.brunel.ac.uk}

works just fine. But, I would like to have macro list which contains these URLs and process them at a later time as I did in Use \foreach loop to execute macro with parameters of macro provided in a list. So, I'd like to be able to say something like:

\DefineMyFormatLinkParameters{%
    *[Main Search Site]{Google}{http://www.google.com},
    [people.brunel.ac.uk]{http://people.brunel.ac.uk/~mastmmg/ssguide/set_work.html#4_32},
    {Yahoo}{http://www.yahoo.com}
}

With the offending line commented I get:

enter image description here

This works fine for the 1st and 3rd case, but not the one with the special TeX characters. I tried escaping them but that doesn't quite work as the links are not click able.

So, what escapes me is how to escape the special characters in such a list?

Code

\documentclass{article}
\usepackage{url}
\usepackage{pgffor}
\usepackage{xparse}
\usepackage{xstring}
\usepackage[colorlinks=true]{hyperref}

\NewDocumentCommand{\FormatLinks}{%
    s%   #1 =* not used yet
    O{}% #2 = optional title
    m%   #3 = Mandatory title
    m%   #4 = URL Link
}{%
    \par
    \hspace*{1.0cm}\href{#4}{#3\IfValueT{#2}{~#2}}%
}%

\newcommand*{\MyFormatLinkParameters}{}% Initialize
\newcommand*{\DefineMyFormatLinkParameters}[1]{%
    \edef\MyFormatLinkParameters{#1}%
}%

\begin{document}
\FormatLinks*[Main Search Site]{Google}{http://www.google.com}
\par\hspace*{1.0cm}\href{http://people.brunel.ac.uk/~mastmmg/ssguide/set_work.html#4_32}{people.brunel.ac.uk}
\FormatLinks{Yahoo}{http://www.yahoo.com}

% Prefer to define a list, and later execute the list:
\DefineMyFormatLinkParameters{%
    *[Main Search Site]{Google}{http://www.google.com},
    %% What changes do I need to make to the following URL to get it pass through the macros.
    % [people.brunel.ac.uk]{http://people.brunel.ac.uk/~mastmmg/ssguide/set_work.html#4_32},
    {Yahoo}{http://www.yahoo.com}
}

\bigskip% 
Following should produce same results as above:\medskip\par
\foreach \x in \MyFormatLinkParameters {%
    \typeout{DEBUG: "\x"}
    \expandafter\FormatLinks\x
}

\end{document}

Best Answer

\documentclass{article}
\usepackage{url}
\usepackage{pgffor}
\usepackage{xparse}
\usepackage{xstring}
\usepackage[colorlinks=true]{hyperref}

\NewDocumentCommand{\FormatLinks}{%
    s%   #1 =* not used yet
    O{}% #2 = optional title
    m%   #3 = Mandatory title
    m%   #4 = URL Link
}{%
    \par
    \hspace*{1.0cm}\href{#4}{#3\IfValueT{#2}{~#2}}%
}%

\newcommand*{\MyFormatLinkParameters}{}% Initialize
\newcommand*{\DefineMyFormatLinkParameters}[1]{%
    \edef\MyFormatLinkParameters{#1}%
}%

\begin{document}
\FormatLinks*[Main Search Site]{Google}{http://www.google.com}
\par\hspace*{1.0cm}\href{http://people.brunel.ac.uk/~mastmmg/ssguide/set_work.html#4_32}{people.brunel.ac.uk}
\FormatLinks{Yahoo}{http://www.yahoo.com}

% Prefer to define a list, and later execute the list:
\DefineMyFormatLinkParameters{%
    *[Main Search Site]{Google}{http://www.google.com},
    %% What changes do I need to make to the following URL to get it pass through the macros.
    {people.brunel.ac.uk}{http://people.brunel.ac.uk/\string~mastmmg/ssguide/set\string_work.html\string#4\string_32},
    {Yahoo}{http://www.yahoo.com}
}

\bigskip% 
Following should produce same results as above:\medskip\par
\foreach \x in \MyFormatLinkParameters {%
    \typeout{DEBUG: "\x"}
    \expandafter\FormatLinks\x
}

\end{document}
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