\ProvidesPackage{bengalidigits}
  [2015/08/07 v.02%
   Formatting of Bengali digits]

\def\bengalidigits#1{\expandafter\@bengali@digits #1@}
\def\@bengali@digits#1{%
  \ifx @#1% terminate
  \else
    \ifcase#1০\or১\or২\or৩\or৪\or৫\or৬\or৭\or৮\or৯\fi
    \expandafter\@bengali@digits
  \fi
}
\endinput