Lazy Tree Structure This structure can be used to represent trees and directed graphs (as infinite trees) in a lazy fashion. Like CCKList, it is a structural type.
type 'a printer = Format.formatter -> 'a -> unittype +'a t = unit -> [ `Nil | `Node of 'a * 'a t list ]val empty : 'a tval is_empty : _ t -> boolval singleton : 'a -> 'a tTree with only one label.
val fold : ('a -> 'b -> 'a) -> 'a -> 'b t -> 'aFold on values in no specified order. May not terminate if the tree is infinite.
val iter : ('a -> unit) -> 'a t -> unitval size : _ t -> intNumber of elements.
val height : _ t -> intLength of the longest path to empty leaves.
class type 'a pset = object ... endAbstract Set structure
val set_of_cmp : cmp:('a -> 'a -> int) -> unit -> 'a psetBuild a set structure given a total ordering.
Depth-first traversal of the tree.
val force : 'a t -> [ `Nil | `Node of 'a * 'b list ] as 'bforce t evaluates t completely and returns a regular tree structure.
Look for an element that maps to Some _.
Example (tree of calls for naive Fibonacci function):
let mk_fib n =
let rec fib' l r i =
if i=n then r else fib' r (l+r) (i+1)
in fib' 1 1 1;;
let rec fib n = match n with
| 0 | 1 -> CCKTree.singleton (`Cst n)
| _ -> CCKTree.node2 (`Plus (mk_fib n)) (fib (n-1)) (fib (n-2));;
let pp_node fmt = function
| `Cst n -> Format.fprintf fmt "%d" n
| `Plus n -> Format.fprintf fmt "%d" n;;
Format.printf "%a@." (CCKTree.pp pp_node) (fib 8);;A pretty-printer using S-expressions and boxes to render the tree. Empty nodes are not rendered; sharing is ignored.
module Dot : sig ... end