是否可默认冻结数组与哈希？是否存在类似# frozen_string_literal: true的数组、哈希全局冻结配置？

Great question! Let's break this down clearly for you:

First off, Ruby doesn't have an official, built-in comment directive like # frozen_string_literal: true that automatically freezes all Arrays and Hashes globally—that feature is specifically designed for strings. But don't worry, there are practical ways to achieve similar behavior without manually calling .freeze on every single collection.

Option 1: Wrap collection creation in helper methods #

The simplest approach is to create your own helper functions that return frozen arrays/hashes right away. This keeps your code clean and cuts down on repetition:

# Define these helpers in a global initializer or utility module
def frozen_arr(*elements)
  Array[*elements].freeze
end

def frozen_hsh(**key_value_pairs)
  Hash[**key_value_pairs].freeze
end

# Usage example
my_arr = frozen_arr(1, 2, 3)
my_hsh = frozen_hsh(name: "Alice", age: 30)

# Both are frozen—modification attempts will throw an error
my_arr << 4 # RuntimeError: can't modify frozen Array

Option 2: Use Ruby Refinements (scoped, safe approach) #

Refinements let you modify the behavior of Array and Hash only within specific scopes (like a single file or module), so you won't accidentally break third-party libraries that depend on mutable collections. Here's how to set it up:

module FrozenCollections
  refine Array do
    def self.[](*args)
      super.freeze
    end

    def self.new(*args, &block)
      super.freeze
    end
  end

  refine Hash do
    def self.[](*args)
      super.freeze
    end

    def self.new(*args, &block)
      super.freeze
    end
  end
end

# Activate the refinement in the file/module where you want frozen collections
using FrozenCollections

# Now these are automatically frozen
fruits = ["apple", "banana"]
user = {id: 1, email: "user@example.com"}

fruits << "cherry" # RuntimeError: can't modify frozen Array

Option 3: Global monkey-patch (NOT recommended) #

You could technically override the default Array/Hash constructors to return frozen instances everywhere, but this is highly discouraged. Many Ruby gems and standard library methods expect mutable collections, and this change could cause unexpected bugs across your entire application. If you still want to see how it works (don't use this in production!):

# Warning: This affects EVERY Array/Hash in your app
class Array
  class << self
    alias_method :original_new, :new
    def new(*args, &block)
      original_new(*args, &block).freeze
    end
  end
end

class Hash
  class << self
    alias_method :original_new, :new
    def new(*args, &block)
      original_new(*args, &block).freeze
    end
  end
end

To recap: There's no official equivalent to frozen_string_literal: true for arrays and hashes, but helper methods or refinements are safe, clean ways to avoid manual .freeze calls. Stick with those instead of risky global modifications!

内容的提问来源于stack exchange，提问作者Moltenhead