So I realise that Doom 3's console cannot understand math operations. This is a massive bummer, cause I cannot do this:
bind = set r_gamma (r_gamma + 0.05)
...in order to implement Thief's ability to change gamma on the fly.
I suppose ZDoom's console has spoiled me.
If implementing basic arithmetic is going to be a tall order, could we at least get inc and dec commands? They would simply inc/dec a cvar by a given parameter.
Eg: bind = inc r_gamma 0.05