<Tr> <Td> April 1999 </Td> <Td> Tcl 8.1 introduces full Unicode support and advanced regular expressions . </Td> </Tr> <Tr> <Td> August 1999 </Td> <Td> Tcl 8.2 introduces Tcl Extension Architecture (TEA) </Td> </Tr> <Tr> <Td> August 2000 </Td> <Td> Tcl Core Team formed, moving Tcl to a more community - oriented development model . </Td> </Tr> <Tr> <Td> September 2002 </Td> <Td> Ninth Tcl / Tk conference (Vancouver). Announcement of starkit packaging system . Tcl 8.4. 0 released . </Td> </Tr>

What are the three fundamental control structures in a high-level language