Turns the symbol into a simple proc, which is especially useful for enumerations. Examples:

  # The same as people.collect { |p| p.name }
  people.collect(&:name)

  # The same as people.select { |p| p.manager? }.collect { |p| p.salary }
  people.select(&:manager?).collect(&:salary)

[Source]

# File activesupport/lib/active_support/core_ext/symbol.rb, line 10
    def to_proc
      Proc.new { |*args| args.shift.__send__(self, *args) }
    end