bibentryfield.tex

\usepackage{keyval}
\makeatletter

%%% Definition of keys
\define@key{reuse}{currentkind}{\def\@tempa{#1}}
\define@key{reuse}{currententry}{\def\reuse@current{#1}}
\def\define@reuse@key#1{\define@key{reuse}{#1}{%
  \global\@namedef{reuse@\reuse@current @#1}{##1}}}
\define@reuse@key{title}
\define@reuse@key{isbn}
\define@reuse@key{url}
\define@reuse@key{year}
\define@reuse@key{note}

%%% The macro substituted to @book, @article, etc.
\def\reuse@find#1#{%
  \lowercase{\setkeys{reuse}{currentkind=#1}}%
  \ifcsname reuse@type@\@tempa\endcsname
    \expandafter\@gobble
  \else
    \begingroup\makeatother
    \expandafter\reuse@extract
  \fi}

%%% the macro for extracting the fields
\def\reuse@extract#1{\setkeys{reuse}{currententry=#1}\endgroup}

%%% Ignore @preamble and @string
\let\reuse@type@preamble\@empty
\let\reuse@type@string\@empty

%%% Error management
\def\reuse@error#1#2{%
  \PackageError{reuse}
    {Undefined key `#1' or empty value for `#2'}
    {The key you used is wrong or the value to `#2' has not been set}}

%%% The four user level macros
\newcommand\newbibfield[1]{\define@reuse@key{#1}}

\def\usebibentry#1#2{\@ifundefined{reuse@#1@#2}
  {\reuse@error{#1}{#2}}
  {\@nameuse{reuse@#1@#2}}}

\newcommand{\usebibentryurl}[2][|]{\@ifundefined{reuse@#2@url}
  {\reuse@error{#2}{url}}
  {\@usebibentryurl{#1}{#2}}}

\@ifpackageloaded{hyperref}{\@tempswatrue}{\@tempswafalse}
\if@tempswa
  \def\@usebibentryurl#1#2{%
    \scantokens{\url{\csname reuse@#2@url\endcsname}\endinput}}
\else
  \def\@usebibentryurl#1#2{%
    \toks@=\expandafter\expandafter\expandafter
      {\csname reuse@#2@url\endcsname}%
    \scantokens\expandafter{%
      \expandafter\url\expandafter#1\the\toks@#1\endinput}}
\fi

\newcommand{\bibinput}[1]{%
  \begingroup
  \catcode`\%=12
  \let\KV@err=\@gobble
  \let\KV@errx=\@gobble
  \let\XKV@err=\@gobble
  \begingroup\lccode`\~=`\@
    \lowercase{\endgroup\let~}\reuse@find
  \catcode`\@=\active \input{#1.bib}\endgroup}

\makeatother