How to use If with on variables

Question

I want to create my own documentclass and use some variables for creating titlepages etc with it.

So what's the best way/package for doing this?

the class file:

\ProvidesClass{myOwnClass}[v0.1]
\newcommand{\myTitlepage}{
    \begin{titlepage}
        \begin{flushright}
        \textsf{
            \thisAutor\\
            E-Mail: \href{mailto:\thisEmail}{\thisEmail}\\[2ex]
            \ifdefined{Phone: \thisPhone}
            \today
            }
        \end{flushright}
    \end{titlepage}
}

the tex-File:

\documentclass{myOwnClass}

% BEGIN_FOLD
% Titel
\newcommand{\thisTitle}{Test}
\newcommand{\thisSubTitle}{a test for \LaTeX}

% Autor
\newcommand{\thisAutor}{Some Name}
\newcommand{\thisEmail}{somename@someprovider.com}
\newcommand{\thisPhone}{}
% END_FOLD

\begin{document}
\myTitlepage
\end{document}

You see, there is no phonenumber given. If it is so I don't want to print this row, but if there is a given phone number it want to print it. What's the best way to do this?

Thanks!

Answer 1

Making users having \newcommand{\thisAuthor}{Some Name} is not a good interface. A better one would be having, in the class file,

\newcommand{\Author}[1]{\renewcommand{\phab@Author}{#1}}
\let\phab@Author\phab@required
\newcommand{\Email}[1]{\renewcommand{\phab@Email}{#1}}
\let\phab@Email\@empty
\newcommand{\Phone}[1]{\renewcommand{\phab@Phone}{#1}}
\let\phab@Phone\@empty

so that you can have something like

\ifx\phab@Phone\@empty
  % do nothing
\else
  Phone: \phab@Phone\\[2ex]
\fi

in your definition of \myTitlepage. If you give a suitable definition of \phab@required you can issue an error if \Author is not in the document. In the document you'll type

\Author{Some Name}
\Email{somename@someprovider.com}

and if \Phone doesn't appear or there is \Phone{}, nothing will be printed.

Here's an example.

Class file myownclass.cls

\ProvidesClass{myownclass}[2014/05/06 v0.1]
\newcommand{\myTitlepage}{%
  \begin{titlepage}
  \raggedleft\sffamily
    {\Large\phab@Title\\}
    \ifx\phab@SubTitle\@empty
    \else
      \vspace{1ex}
      \phab@SubTitle\\
    \fi
    \vspace{4ex}
    \phab@Author\\
    \ifx\phab@Email\@empty
    \else
      E-Mail: \href{mailto:\phab@Email}{\phab@Email}\\[2ex]
    \fi
    \ifx\phab@Phone\@empty
    \else
      Phone: \phab@Phone\\[2ex]
    \fi
    \today
  \end{titlepage}
}

\newcommand{\Title}[1]{\renewcommand{\phab@Title}{#1}}
\newcommand{\SubTitle}[1]{\renewcommand{\phab@SubTitle}{#1}}
\newcommand{\Author}[1]{\renewcommand{\phab@Author}{#1}}
\newcommand{\Email}[1]{\renewcommand{\phab@Email}{#1}}
\newcommand{\Phone}[1]{\renewcommand{\phab@Phone}{#1}}

% Initializations
\newcommand\phab@required[1]{The field `#1' is required}

\newcommand\phab@Title{\phab@required{Title}}
\let\phab@SubTitle\@empty
\newcommand\phab@Author{\phab@required{Author}}
\let\phab@Email\@empty
\let\phab@Phone\@empty

\LoadClass{article}

\AtBeginDocument{\RequirePackage{hyperref}}

\endinput

Document phab.tex

\documentclass{myownclass}

\Title{Test}
\SubTitle{a test for \LaTeX}

% Author
\Author{Some Name}
\Email{somename@someprovider.com}
\Phone{}
% END_FOLD

\begin{document}
\myTitlepage
\end{document}

Output