VHDL-2008 allows sequential signal and variable assignment with conditional signals. For example, a register with an enable would be written as the following:
process(clk) begin
if clk'event and clk='1' then
if enable then
my_reg <= my_input;
end if;
end if;
end process;
With VHDL-2008, this can now be written as the following:
process(clk) begin
if clk'event and clk='1' then
my_reg <= my_input when enable else my_reg;
end if;
end process;