to_proc & map

gistfile1.txt

def meth(a, b, c)
  [c, b, a]
end
ary = [1, 2, 3]
meth(*ary) # => [3, 2, 1]

class Symbol
  def to_proc2
    Proc.new { |element| element.send self }
  end
end

class Array
  def to_proc
    method_name, *args = self
    Proc.new { |obj| obj.send method_name, *args }
  end
  
  def to_proc2
    method_name = first
    args = self[1..-1]
    Proc.new { |obj| obj.send method_name, *args }
  end
end

:upcase.to_proc2.call("abc") # => "ABC"

%w[abc def ghi].map(&:upcase) # => ["ABC", "DEF", "GHI"]
%w[abc def ghi].map(&[:split, ""]) # => [["a", "b", "c"], ["d", "e", "f"], ["g", "h", "i"]]

a, *b = [1, 2, 3]
a # => 1
b # => [2, 3]