A tree represents a generated value and its successive shrunk values.
Conceptually a pseudo-randomly generated value is packaged with its shrunk values. This coupling - called "integrated shrinking" - in a single type has a major benefit: most generators get shrinking "for free" by composing from smaller generators, and shrinking does not break invariants (e.g. shrinks of a positive number are always positive).
A tree of random generated values, where the root contains the value used for the test, and the sub-trees contain shrunk values (as trees, to be able to shrink several times a value) used if the test fails.
val root : 'a t -> 'aroot tree returns the root value of the tree of generated values t.
children tree returns the direct sub-trees of the tree of generated values t.
val pp :
?depth:int ->
(Format.formatter -> 'a -> unit) ->
Format.formatter ->
'a t ->
unitpp ?depth pp_a ppf tree pretty-prints the tree of generated values tree using the pretty-print formatter ppf. Values of type 'a will be printed using the given pretty-printer pp_a.
As a tree t can be potentially huge when fully evaluated, you can control the maximum depth the printer goes with depth.
None means "everything"0 means "only the root"1 means "the root and its direct shrinks"2 means "the root, its direct shrinks, and the shrinks of its shrinks"