callable.rb

class Symbol
  def call(*args, &block)
    if block
      -> recv { to_proc.(recv, *args, &block) }
    else
      -> recv { to_proc.(recv, *args) }
    end
  end
end

class Array
  def call(*args, &block)
    symbol, * = *self
    if block
      -> recv { symbol.to_proc.(recv, *args, &block) }
    else
      -> recv { symbol.to_proc.(recv, *args) }
    end
  end
  def to_proc
    -> callables {
      -> recv {
        callables.inject(recv) {|r, c| c.call(r) }
      }
    }.(self.map {|_| symbol, *args = *_.first ; symbol.(*args) })
  end
end

class Hash
  def call(*args, &block)
    symbol, * = *self.first
    if block
      -> recv { symbol.to_proc.(recv, *args, &block) }
    else
      -> recv { symbol.to_proc.(recv, *args) }
    end
  end
  def to_proc
    -> callables {
      -> recv {
        callables.inject(recv) {|r, c| c === r }
      }
    }.([*self].map {|symbol, *args| symbol.(*args) })
  end
end

p [*0..10].map(&:*.(2))
p [*0..10].map(&{:* => 2, :+ => 3})
p [*0..10].map(&[{:* => 3}, {:/ => 2}, {:+ => 1}])