eNotes.txt

## TODO

test unionMerge and intersectionMerge

## Consider adding

addMerge

incl alias for add
excl alias for del
card alias for len

## Consider adding tree/map-like equivalents to:

proc filter[T](s: openArray[T]; pred: proc (x: T): bool {...}): seq[T] {...}
Returns a new sequence with all the items that fulfilled the predicate.

proc all[T](s: openArray[T]; pred: proc (x: T): bool {...}): bool
Iterates through a container and checks if every item fulfills the predicate.

proc any[T](s: openArray[T]; pred: proc (x: T): bool {...}): bool
Iterates through a container and checks if some item fulfills the predicate.

proc zip[S, T](s1: openArray[S]; s2: openArray[T]): seq[tuple[a: S, b: T]]
Returns a new sequence with a combination of the two input containers.
For convenience you can access the returned tuples through the named fields a and b. 
If one container is shorter, the remaining items in the longer container are discarded.

## Consider subclassing BBTree as BBSet with no Val field

## Determine if there is a way to use object variants or subclasses to reduce memory consumption
without making the code a lot more complex; e.g., BBTreeKind = enum One, TwoL, TwoR, Node, and 
cased out funcs for size, left, right, key, and val

## Note

From sequtils, 
template toSeq(iter: untyped): untyped
Transforms any iterator into a sequence.

## Done

These are automatic:
`in` alias for contains
`notin` alias for not contains

proc map[T, S](s: openArray[T]; op: proc (x: T): S {...}): seq[S] {...}
Returns a new sequence with the results of op applied to every item in the container s.
Since the input is not modified you can use this version of map to transform the type 
of the elements in the input container.

fold of some kind, at least foldr though the sequtils version doesn't tahe a base value

## Testing

[Suite] test int,int bbtree.nim
  [OK] empty tree is ordered, balanced, has length zero
  [OK] one entry tree is ordered, balanced, has length one
  [OK] one entry tree lookup works
  [OK] add items in increasing key order, check ordered, balanced, has length 21
  [OK] add items in decreasing key order, check ordered, balanced, has length 44
  [OK] check that some items are in the length 44 tree
  [OK] check succ and pred functions in the length 44 tree
  [OK] delete some items, check, check ordered, balanced, and length
  [OK] delete random items, check, check ordered, balanced, and length
  [OK] using add to replace values

[Suite] test opacity bbtree.nim
  [OK] opacity

[Suite] test map and fold bbtree.nim
  [OK] fold to string
  [OK] map to string

[Suite] test set funcs of bbtree.nim
  [OK] toSet
  [OK] Nim compat
  [OK] Pairs as keys
  [OK] ints as set keys

[Suite] random stress test of bbtree.nim
        ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
        CPU time 13063.857357794 s for 500000 loops, averaging 0.026127714715588 s per loop
        random q: 254981 inserts, 245019 deletes, 9962 qintree, 9962 final size
  [OK] timed random tree iterations
nim-bbtree e$