type ustring* = distinct string
converter toUString*(s: string): ustring = ustring(s)
proc `[]`*(s: ustring, i: int): ustring = s
echo "abcdefgh"[1..^2]
dHlwZSB1c3RyaW5nKiA9IGRpc3RpbmN0IHN0cmluZwoKY29udmVydGVyIHRvVVN0cmluZyooczogc3RyaW5nKTogdXN0cmluZyA9IHVzdHJpbmcocykKCnByb2MgYFtdYCooczogdXN0cmluZywgaTogaW50KTogdXN0cmluZyA9IHMKCmVjaG8gImFiY2RlZmdoIlsxLi5eMl0K