Merge pull request #14 from JuliaCollections/isempty

Add isempty to BinaryTree interface

Author: juliohm

Project.toml

@@ -1,7 +1,7 @@
 name = "BinaryTrees"
 uuid = "289e92be-c05a-437b-9e67-5b0c799891f8"
 authors = ["Elias Carvalho <[email protected]> and contributors"]
-version = "0.1.1"
+version = "0.1.2"
 
 [deps]
 AbstractTrees = "1520ce14-60c1-5f80-bbc7-55ef81b5835c"

README.md

@@ -29,6 +29,9 @@ using BinaryTrees
 
 tree = AVLTree{Int,Float64}()
 
+# check if tree is empty
+BinaryTree.isempty(tree)
+
 # insert nodes into the tree
 BinaryTrees.insert!(tree, 2, 2.2) # root node
 BinaryTrees.insert!(tree, 1, 1.1) # left node
@@ -42,6 +45,9 @@ BinaryTrees.search(tree, 2) # root node
 BinaryTrees.search(tree, 1) # left node
 BinaryTrees.search(tree, 3) # right node
 
+# search previous and next node using keys
+BinaryTrees.prevnext(tree, 2)
+
 # delete nodes from the tree
 BinaryTrees.delete!(tree, 1)
 BinaryTrees.delete!(tree, 3)

src/binarytree.jl

@@ -55,6 +55,13 @@ Root node of the `tree`.
 """
 root(tree::BinaryTree) = tree.root
 
+"""
+    BinaryTrees.isempty(tree)
+
+Tell whether or not the `tree` is empty.
+"""
+isempty(tree::BinaryTree) = isnothing(root(tree))
+
 """
     BinaryTrees.search(tree, key)
 

test/runtests.jl

@@ -235,8 +235,15 @@ const BT = BinaryTrees
     @test BT.key.(BT.prevnext(tree, 5)) == (4, 6)
     @test BT.prevnext(tree, nothing) == (nothing, nothing)
 
+    # checking for emptiness
+    tree = AVLTree{Int,Int}()
+    @test BT.isempty(tree)
+    tree = AVLTree{Int,Float64}()
+    @test BT.isempty(tree)
+
     # type stability
     tree = AVLTree{Int,Int}()
+    @inferred BT.isempty(tree)
     @inferred BT.insert!(tree, 2, 20)
     @inferred BT.insert!(tree, 1, 10)
     @inferred BT.insert!(tree, 3, 30)