% engine=luatex 

\definefontfeature
  [curs]
  [mode=node,language=dflt,script=arab,
   init=yes,medi=yes,fina=yes,isol=yes,
   liga=yes,dlig=yes,rlig=yes,clig=yes,
   mark=yes,mkmk=yes,kern=yes,curs=yes]

\definefontfeature
  [nocurs]
  [mode=node,language=dflt,script=arab,
   init=yes,medi=yes,fina=yes,isol=yes,
   liga=yes,dlig=yes,rlig=yes,clig=yes,
   mark=yes,mkmk=yes,kern=yes]

\font\CArab = SimplifiedNaskh*curs at 32pt
\font\NArab = SimplifiedNaskh*nocurs at 32pt

\setcharactermirroring[1]

\starttext
\textdir TRT\pardir TRT
\CArab
في فى قي قى فئ قئ


\NArab
في فى قي قى فئ قئ

\stoptext