Context Free Grammars

Hello /prog/, recently I have been learning Context Free Grammars and there are some issues that are bugging me. I figured I might as well bring them up here in case anyone knew since the book is a bag of dicks that, in my opinion, is criminally minimalist.

Namely, is there some method by which a person can find the context-free grammar describing the complement of some other  context-free grammar? The problem of constraining particularly large complements makes simply trying to think up a grammar rather difficult because it has to both produce a staggering variation of strings while somehow avoiding a handful of rather specific cases.

Also, aside from my question, general thread for CFGs and context free languages.

What a retarded question. Clearly you don't understand grammars.

>>2
If you could illuminate precisely how I am retarded, it may help me be less so. You're likely just trolling, but any port in a storm.

>>3
any port in a storm.
Is that a metaphore for "even the anus of a gay man during a dry spell"?

>>1
The set of context free languages is not closed under complementation.

>>5
Uh-oh, that's some advanced maths going on here! I don't think the freshman that >>1 is already had this on his lectures!

>>5
I know that (a previous problem even had me prove it). Nonetheless the book gives me problems wanting the grammars describing the complement of other grammars. I figured there'd be some general rules of thumb to go by provided you have an assurance that yes, the result is in fact still context free.

I'm sorry, I should have elaborated in my opening post on that.

>>6
Fuck you and your high horse. Faggot.

>>6
Obviously English is your second language.

>>9
Truly a mark of intelligence and faggotry.

>>10
Wait, what?

Are you GAY?
Are you a NIGGER?
Are you a GAY NIGGER?

If you answered "Yes" to all of the above questions, then GNAA (GAY NIGGER ASSOCIATION OF AMERICA) might be exactly what you've been looking for!