Try this
DEFINE VARIABLE m_char AS CHARACTER NO-UNDO INIT "test testest 123456789".
DEFINE VARIABLE i AS INTEGER NO-UNDO.
DEFINE VARIABLE list AS CHARACTER NO-UNDO INIT "a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z, ".
DEFINE VARIABLE m_final AS CHARACTER NO-UNDO.
REPEAT i =...