Parametric polymorphism: Difference between revisions

Line 758:

end

Tree(v::T) where {T} = Tree(v, nothing, nothing) # Single arg constructor

Tree(v::T) where T = Tree(v, nothing, nothing) # Single arg constructor

"""

~~Applies~~ `f` (element-wise and in-place) to the values in tree `bt`.

Apply `f` (element-wise and in-place) to the values in tree `bt`.

~~Prints~~ the tree in an s-expression ~~form~~ *for demonstrative purposes only*,

Also prints the tree like an s-expression *for demonstrative purposes only*,

new types should override the `show()` function for pretty-printing.

"""

function map!(f::Function, bt::Tree{T}) where T

bt.val = f(bt.val)

bt.val= f(bt.val)

print(" (" * string(bt.val)) # ~~Demo~~ only

print(" (" * string(bt.val)) # Demonstration only

bt.lchild !== nothing && map!(f, bt.lchild)

bt.rchild !== nothing && map!(f, bt.rchild)

print(")") # ~~Demo~~ only

print(")") # Demonstration only

end

function test_treemap()

bt = Tree(0,

inttree = Tree(0,

Tree(1,

Tree(3),

Tree(5)),

Tree(2,

Tree(4),

~~Tree(6)~~))

nothing))

map!(x -> 2x^2, bt)

map!(x -> 2x^2, inttree) # Pass an anonymous function

# (0 (2 (18) (50)) (8 (32~~) (72~~)))

# (0 (2 (18) (50)) (8 (32)))

println()

strtree = Tree("hello",

Tree("world!",

Tree("Julia"),

nothing),

Tree("foo",

Tree("bar"),

Tree("baz")))

map!(uppercase, strtree)

# (HELLO (WORLD! (JULIA)) (FOO (BAR) (BAZ)))

end</lang>