%% 
%%  Die DANTE-Edition
%%  Ein Beispiel der LaTeX Referenz
%%  3. Auflage
%% 
%% 
%%  Copyright (C) 2013 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{193.16928pt}
\setlength\parindent{0pt}
\usepackage{xtemplate,xparse}
\ExplSyntaxOn
\DeclareObjectType { names } { 2 }

% das Interface für das Template `fullname':
\DeclareTemplateInterface { names } { fullname } { 2 }
  {
    reversed           : boolean   = false ,
    use-last-name      : boolean   = true  ,
    use-first-name     : boolean   = true  ,
    last-name-format   : tokenlist         ,
    first-name-format  : tokenlist         ,
  }
% das Interface für das Template `initial':
\DeclareTemplateInterface { names } { initial } { 2 }
  {
    reversed           : boolean   = false ,
    use-last-name      : boolean   = true  ,
    use-first-name     : boolean   = true  ,
    last-name-format   : tokenlist         ,
    first-name-format  : tokenlist         ,
    last-name-initial  : boolean   = false ,
    first-name-initial : boolean   = true  ,
  }

% erst einmal die Variablen:
\bool_new:N \l_names_reversed_bool
\bool_new:N \l_names_use_last_bool
\bool_new:N \l_names_use_first_bool
\tl_new:N   \l_names_last_format_tl
\tl_new:N   \l_names_first_format_tl

% und dann der Template-Code:
\DeclareTemplateCode { names } { fullname } { 2 }
  {
    reversed           = \l_names_reversed_bool   ,
    use-last-name      = \l_names_use_last_bool   ,
    use-first-name     = \l_names_use_first_bool  ,
    last-name-format   = \l_names_last_format_tl  ,
    first-name-format  = \l_names_first_format_tl ,
  }
  {
    \AssignTemplateKeys
    \bool_if:NTF \l_names_reversed_bool
      {
        \bool_if:NT \l_names_use_last_bool
          { { \tl_use:N \l_names_last_format_tl #2 } }
        \bool_if:nT { \l_names_use_first_bool && \l_names_use_last_bool }
          { , ~ }
        \bool_if:NT \l_names_use_first_bool
          { { \tl_use:N \l_names_first_format_tl #1 } }
      }
      {
        \bool_if:NT \l_names_use_first_bool
          { { \tl_use:N \l_names_first_format_tl #1 } }
        \bool_if:nT { \l_names_use_first_bool && \l_names_use_last_bool }
          { \tl_use:N \c_space_tl }
        \bool_if:NT \l_names_use_last_bool
          { { \tl_use:N \l_names_last_format_tl #2 } }
      }
  }

% zwei weitere Variablen:
\bool_new:N \l_names_last_initial_bool
\bool_new:N \l_names_first_initial_bool

% Hilfsfunktion:
\cs_new:Npn \names_get_initial:w #1#2 \q_stop { #1 . }

% der Template-Code:
\DeclareTemplateCode { names } { initial } { 2 }
  {
    reversed           = \l_names_reversed_bool      ,
    use-last-name      = \l_names_use_last_bool      ,
    use-first-name     = \l_names_use_first_bool     ,
    last-name-format   = \l_names_last_format_tl     ,
    first-name-format  = \l_names_first_format_tl    ,
    last-name-initial  = \l_names_last_initial_bool  ,
    first-name-initial = \l_names_first_initial_bool ,
  }
  {
    \AssignTemplateKeys
    \bool_if:NTF \l_names_reversed_bool
      {
        \bool_if:NT \l_names_use_last_bool
          {
            \group_begin:
              \tl_use:N \l_names_last_format_tl
              \bool_if:NTF \l_names_last_initial_bool
                { \names_get_initial:w #2 \q_stop }
                { #2 }
            \group_end:
          }
        \bool_if:nT { \l_names_use_first_bool && \l_names_use_last_bool }
          { , ~ }
        \bool_if:NT \l_names_use_first_bool
          {
            \group_begin:
              \tl_use:N \l_names_first_format_tl
              \bool_if:NTF \l_names_first_initial_bool
                { \names_get_initial:w #1 \q_stop }
                { #1 }
            \group_end:
          }
      }
      {
        \bool_if:NT \l_names_use_first_bool
          {
            \group_begin:
              \tl_use:N \l_names_first_format_tl
              \bool_if:NTF \l_names_first_initial_bool
                { \names_get_initial:w #1 \q_stop }
                { #1 }
            \group_end:
          }
        \bool_if:nT { \l_names_use_first_bool && \l_names_use_last_bool }
          { \tl_use:N \c_space_tl }
        \bool_if:NT \l_names_use_last_bool
          {
            \group_begin:
              \tl_use:N \l_names_last_format_tl
              \bool_if:NTF \l_names_last_initial_bool
                { \names_get_initial:w #2 \q_stop }
                { #2 }
            \group_end:
          }
      }
  }

% ein paar Instanzen, erst mal mit dem Template `fullname':
\DeclareInstance { names } { standard } { fullname } {}
\DeclareInstance { names } { it-rev } { fullname }
  {
    first-name-format = \itshape ,
    reversed          = true
  }
\DeclareInstance { names } { first-only } { fullname }
  { use-last-name = false }
% und dann mit `initial':
\DeclareInstance { names } { init-first } { initial } {}
\DeclareInstance { names } { init-it-rev } { initial }
  {
    first-name-format = \itshape ,
    reversed          = true
  }
\DeclareInstance { names } { init-all } { initial }
  { last-name-initial = true }

% eine weitere Hilfsvariable:
\tl_new:N  \l_names_instance_tl
\tl_set:Nn \l_names_instance_tl { standard }

% der interne Befehl:
\cs_new:Npn \names_typeset_name:nnn #1#2#3
  {
    \IfInstanceExistTF { names } { #1 }
      { \UseInstance { names } { #1 } }
      { \UseInstance { names } { standard } }
    { #2 } { #3 }
  }
\cs_generate_variant:Nn \names_typeset_name:nnn { V }

% der Benutzerbefehl:
\DeclareDocumentCommand \name { o > { \SplitArgument { 1 } { ~ } } m }
  {
    \group_begin:
      \IfNoValueF { #1 } { \tl_set:Nn \l_names_instance_tl { #1 } }
      \names_typeset_name:Vnn \l_names_instance_tl #2
    \group_end:
  }
\ExplSyntaxOff
%StartShownPreambleCommands
\usepackage{xtemplate,xparse}
\usepackage[T1]{fontenc}
\usepackage{libertine}
\usepackage[utf8]{inputenc}
%StopShownPreambleCommands
\begin{document}
\name{Herbert Voß} \\
\name[it-rev]{Herbert Voß} \\
\name[first-only]{Herbert Voß} \\
\name[init-first]{Herbert Voß} \\
\name[init-it-rev]{Herbert Voß} \\
\name[init-all]{Herbert Voß}
\end{document}