:: [[a]] -> [[a]] package:extrapolate

Normalizes tiers by removing up to 12 empty tiers from the end of a list of tiers.

normalizeT [xs0,xs1,...,xsN,[]]     =  [xs0,xs1,...,xsN]
normalizeT [xs0,xs1,...,xsN,[],[]]  =  [xs0,xs1,...,xsN]

The arbitrary limit of 12 tiers is necessary as this function would loop if there is an infinite trail of empty tiers.

Resets any delays in a list-of tiers. Conceptually this function makes a constructor "weightless", assuring the first tier is non-empty.

reset [[], [], ..., xs, ys, zs, ...]  =  [xs, ys, zs, ...]

reset [[], xs, ys, zs, ...]  =  [xs, ys, zs, ...]

reset [[], [], ..., [x], [y], [z], ...]  =  [[x], [y], [z], ...]

Typically used when defining Listable instances:

instance Listable <Type> where
tiers  =  ...
\/ reset (cons<N> <Constructor>)
\/ ...

Be careful: do not apply reset to recursive data structure constructors. In general this will make the list of size 0 infinite, breaking the tiers invariant (each tier must be finite).

Delays the enumeration of tiers. Conceptually this function adds to the weight of a constructor.

delay [xs, ys, zs, ... ]  =  [[], xs, ys, zs, ...]

delay [[x,...], [y,...], ...]  =  [[], [x,...], [y,...], ...]

Typically used when defining Listable instances:

instance Listable <Type> where
tiers  =  ...
\/ delay (cons<N> <Constructor>)
\/ ...