Integrate the left input signal over time, but apply the given
correction function to it. This can be used to implement collision
detection/reaction.
The right signal of type
w is the
world value. It is
just passed to the correction function for reference and is not used
otherwise.
The correction function must be idempotent with respect to the world
value:
f w (f w x) = f w x. This is necessary and sufficient
to protect time continuity.