Constant strings

[Enrico Colombini <erix@...>]

Is there a reason why adjacent constant strings are not considered as a
single string, like in C? For example, this is not allowed in Lua:

 Show("Suppose this is a long string "
      "broken in two lines for readability")

If I use "..", does it have a cost or are the strings concatenated into a
single string only once at compile time?

  Enrico