
\ctxlua{fonts.otf.features.register_base_substitution('ss08')} % for texlive's context
\definefontfeature[virtualmath]      [virtualmath][ss08=yes]
\definefontfeature[math-text]        [virtualmath][mathalternates=yes,ssty=no]
\definefontfeature[math-script]      [virtualmath][mathalternates=yes,ssty=1,mathsize=yes]
\definefontfeature[math-scriptscript][virtualmath][mathalternates=yes,ssty=2,mathsize=yes]

\setupbodyfont[xits]

\starttext
\startbuffer[integrals]
  \ctxlua {
  local uchar = unicode.utf8.char
  for i = 0x222B, 0x2233 do
    tex.sprint([[\Umathchar"1"0`]]..uchar(i)..[[\nolimits_{x}^{y}]])
  end
  for i = 0x2A0B, 0x2A1C do
    tex.sprint([[\Umathchar"1"0`]]..uchar(i)..[[\nolimits_{x}^{y}]])
  end
  }
\stopbuffer

\startTEXpage
  \startformula
    \textstyle\getbuffer[integrals]
  \stopformula
\stopTEXpage

\startTEXpage
  \startformula
    \getbuffer[integrals]
  \stopformula
\stopTEXpage

\stoptext
