5H. repeat-statement (REPEAT)
-----------------------------
REPEAT, UNTIL

syntax:		REPEAT
		UNTIL <exp>

builds a repeat-until block: it will continue to loop this block until
<exp>=TRUE. Example:

REPEAT
  WriteF('Do you really, really wish to exit this program?\n')
  ReadStr(stdout,s)
UNTIL StrCmp(s,'yes please!')