for "0" to "9" as \1
  <letter \1> : "\1"
end for

for "a" to "z" as \1
  let \2 : "\sub(\1 \sub("a" "A"))"
  <letter \1> : "\1"
  <shift letter \1> : "\2"
  <caps letter \1> : "\2"
  <shift caps letter \1> : "\1"
end for