\starttext

\unexpanded\def\dotestchar#1#2#3%
  {\dontleavehmode
   \begingroup
   \tt
   (%
   \uchexnumbers{#3}%
   :%
   \begingroup
   \definedfont[name:#1*default]#2%
   \endgroup
   ,%
   \begingroup
   \definedfont[name:#1*default]#2\char#3%
   \endgroup
   ,%
   \begingroup
   \definefontfeature[default#3][default][variant=#3]%
   \definedfont[name:#1*default#3]#2%
   \endgroup
   )%
   \endgroup}

\unexpanded\def\testchar#1#2%
  {\dostepwiserecurse{"E0100}{"E010F}{1}{\dotestchar{#1}{#2}{##1}\space}%
  %\dostepwiserecurse {"FE00} {"FE01}{1}{\dotestchar{#1}{#2}{##1}\space}%
  }

\testchar{SourceHanSansSCMedium}{曜}\blank
\testchar{SourceHanSansSCMedium}{邉}\blank % 37001
\testchar{SourceHanSansSCMedium}{邊}\blank % 37002

\stoptext
