Is this statement legal?

[Immocation]

I'm trying to make a JK flip-flop in VHDL, and I'm trying to make the 'hold' state sequence.

So inside my process I have a statement that roughly says

if j = '1' and k = '1'
then q <= not q

I'm getting a compiler error statement saying "Can not read output q".

I can sort of understand this... it can't assign a value to q at first because q is not defined immediately. However, I have seen this done before.

Is it legal to do this? Is there a better way?

 

[Tomasz Turek]

it should be:

if (j = '1' and k = '1')
then q <= not q