Custom email macro

Question

I'd like to define an email macro that does the following:

Input: \domainemail{Jack Johnson}

Output: Jack Johnson

The output should be a highlighted hyperlink that reads "mailto:[email protected]".

What I have is

\usepackage[colorlinks=true,allcolors=DarkBlue]{hyperref}
\newcommand{\domainemail}[1]{\href{mailto:#[email protected]}{#1}}

which produces the link "mailto:Jack [email protected]"

How can I replace the space with a period and upper- with lowercase initials? I tried enclosing #1 with \lowercase but that seems to break the hyperlink.

Bonus

Extra points if \domainemail can handle umlauts (including ß) and multiple first and last names, e.g.

Input: \domainemail{Johnson-Löffler, Jack Björn}

Output: Johnson-Löffler, Jack Björn with hyperlink "mailto:[email protected]"

Answer 1

Some parts of the code are based on another answer of mine. With \addtranslations you set up the “translation” you wish for the Unicode characters you need. Anyway, for very strange names, you can use the optional argument to \domainemail.

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{xparse}
\usepackage{hyperref}

\ExplSyntaxOn

\NewDocumentCommand{\addtranslations}{m}
 {
  \clist_map_inline:nn { #1 }
   {
    \seq_gput_right:Nn \g_casimir_search_replace_seq { ##1 }
   }
 }

\NewDocumentCommand{\domainemail}{om}
 {
  \IfNoValueTF { #1 }
   {
    \casimir_domainemail:n { #2 }
   }
   {
    \casimir_href:nn { #1 } { #2 }
   }
 }

\seq_new:N \g_casimir_search_replace_seq
\tl_new:N \l_casimir_input_tl
\cs_generate_variant:Nn \tl_lower_case:n { V }

\cs_new_protected:Nn \casimir_href:nn { \href{mailto:#[email protected]}{#2} }
\cs_generate_variant:Nn \casimir_href:nn { V }

\cs_new_protected:Nn \casimir_domainemail:n
 {
  \seq_set_from_clist:Nn \l__casimir_domainemail_temp_seq { #1 }
  \int_compare:nTF { \seq_count:N \l__casimir_domainemail_temp_seq > 1 }
   {
    \tl_set:Nx \l_casimir_input_tl
     {
      \seq_item:Nn \l__casimir_domainemail_temp_seq { 2 }
      .
      \seq_item:Nn \l__casimir_domainemail_temp_seq { 1 }
     }
    \tl_remove_all:Nn \l_casimir_input_tl { ~ }
   }
   {
    \seq_set_split:Nnn \l__casimir_domainemail_temp_seq { ~ } { #1 }
    \tl_set:Nx \l_casimir_input_tl
     {
      \seq_use:Nn \l__casimir_domainemail_temp_seq { . }
     }
   }
  \tl_set:Nx \l_casimir_input_tl { \tl_lower_case:V \l_casimir_input_tl }
  \seq_map_inline:Nn \g_casimir_search_replace_seq
   {
    \tl_replace_all:Nnn \l_casimir_input_tl ##1
   }
  \casimir_href:Vn \l_casimir_input_tl { #1 }
 }
\ExplSyntaxOff

% set up the translations

\addtranslations{
  {æ}{ae},
  {ä}{ae},
  {ö}{oe},
  {ü}{ue},
  {ß}{ss},
  {ñ}{n},
  {é}{e},
}



\begin{document}

\domainemail{Jack Johnson}

\domainemail{Johnson-Löffler, Jack Björn}

\domainemail{Äöß, Reñé Joseph}

\domainemail[strange]{Some strange name}

\end{document}

Answer 2

Adding the period is simple with \add@period#1 #2{#1.#2} using space as a delimiter of the first and the second name, typing it with a . then.

Transferring the names into lower case is more difficult, in my point of view, but I used \text_lowercase:n from expl3 which provides this facility.

\documentclass{article}
\usepackage[svgnames,dvipsnames,x11names]{xcolor}
\usepackage[colorlinks=true,allcolors=DarkBlue]{hyperref}
\usepackage{expl3}

\makeatletter
\def\add@period#1 #2{#1.#2}%
\ExplSyntaxOn
\newcommand{\addperiod}[1]{%
  \text_lowercase:n{\add@period#1}% Expandable lower case
}
\ExplSyntaxOff
\makeatother


\newcommand{\domainemail}[1]{%
  \href{mailto:\addperiod{#1}@domain.org}{#1}%
}


\begin{document}
\domainemail{Jack Johnson}
\end{document}