structs_and_arrays.rb

# From the docs of Kernel.array
#   First tries to call to_ary on arg, then to_a.
#   http://ruby-doc.org/core-2.2.3/Kernel.html#method-i-Array

# Ok, so does a struct respond to to_ary?

Monkey = Struct.new(:name, :favorite_color)
m = Monkey.new("George", "Yellow")
m.respond_to?(:to_ary)
#=> false

# So, does it respond to to_a?

m.respond_to?(:to_a)
#=> true

# And what is the behavior of struct's .to_a?
#   Returns the values for this struct as an Array.
#   http://ruby-doc.org/core-2.2.3/Struct.html#method-i-to_a

# So...

m.to_a
#=> ["George", "Yellow"]

# and

Array(m)
#=> ["George", "Yellow"]

# maybe not the principle of least surprise, but it makes sense when you dig in.

# What about non-structs?

Array(1)
#=> [1]

# so, to_ary?

1.respond_to(:to_ary?)
#=> false

# Ok, to_a?

1.respond_to(:to_a?)
#=> false

# ...ok...so?
# https://github.com/ruby/ruby/blob/f830ace8a831a954db7a6aae280a530651a5b58a/object.c#L3133
# ¯\_(ツ)_/¯