simple-immutable

Turns a nested data structure into a immutable ruby object implementing dot and [] accessors.

Usage

Immutable = ::Simple::Immutable

data =
  {
    a: "a-value",
    "b": "b-value",
    "child": {
      name: "childname",
      grandchild: {
        name: "grandchildname"
      }
    },
    "children" => [
      "anna",
      "arthur",
      {
        "action" => {
          keep_your_mouth_shut: true
        }
      }
    ]
  }
  
imm = Immutable.create(data)

imm.a # -> 'a-value'
imm.children.class                          # -> Array
imm.children[2].action.keep_your_mouth_shut # -> true
imm.children.foo                            # NoMethodError (undefined method `foo' for #<Array:0x00007fb90f1be390>)
imm.children.first.foo                      # NoMethodError (undefined method `foo' for "anna":String)

If an attribute is not defined in the immutable (or in any sub-immutable) we raise a NameError

imm.unknown                                 # NameError (unknown immutable attribute 'unknown')

One can check for an attribute by appending a "?". If the attribute is not defined this returns +nil+ instead of raising an error.

imm.a?                                      # 'a-value'
imm.unknown?                                # nil
imm.foo?.bar?                               # also nil

When building an immutable one can provide a "fallback" hash in addition to the returned hash. If a key does not exist in the passed in data it will be fetched from the "fallback" data. This is rarely useful, but can provide effectove optimization in some cases.