Need Help with Sequence detector Code errors

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Hello All,

I am trying to create a finite state machine which detects the input sequence 1011. I have written the code however I am getting about 21 errors. I am new to VHDL so what looks syntactically correct to me may be totally wrong. I would greatly appreciative if there is anybody who could take a look at my code and offer some advice as to what is creating the errors. My code is attached. Thanks

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The simplest way to detect a sequence is to use delay to remember past values(shift register):

in a clocked process use signal temp of 4 bits then

temp(3) <= data;
temp(2) <= temp(3);
temp(1) <= temp(2);
temp(0) <= temp(1);
if temp = "1011" then
    sequence <= '1';
else
   sequence <= '0';
end if;

you can also just code

temp <= data & temp(3 downto 1);

you may reverse the shift direction depending on which way suits your sequence sense.

temp <= temp(2 downto 0) & data;