not sure if this is what you want or not ? but this is what i was meaning
Code:
 
Menu Channel {
  Text Conversion
  .Convertor {
    set %ttc $$?="Convert Text:"
    if ( a isin %ttc ) { set %ttc $replace(%ttc,a,1) }
    if ( b isin %ttc ) { set %ttc $replace(%ttc,b,2) }
    if ( c isin %ttc ) { set %ttc $replace(%ttc,c,3) }
    say %ttc 
  }
}

if i want to be cool i would learn my abc's
would come out like this
if i w1nt to 2e 3ool i would le1rn my 123's
hope that helps