feat: ArrayOf and Enumerable types

Author: joelmoss

README.md

@@ -101,6 +101,29 @@ sig name: T.RangeOf(Integer)
 def create(name: 1...2); end
 ```
 
+#### `ArrayOf`
+
+Value **MUST** be an Array of the given type
+
+```ruby
+sig names: T.ArrayOf(String)
+def create(names: ['Joel', 'Ash']); end
+```
+
+#### `Enumerable`
+
+Value **MUST** be an Enumerable of the optional given type
+
+```ruby
+sig users: T.Enumerable
+def create(users: [1, 2]); end
+```
+
+```ruby
+sig users: T.Enumerable(User)
+def create(users: User.all); end
+```
+
 #### `Any`
 
 Value **MUST** be any of the given list of values, that is, the value must be one of the given list.

lib/delivered.rb

@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 module Delivered
+  EXPENSIVE_TYPE_CHECKS = ENV['DELIVERED_EXPENSIVE_TYPE_CHECKS'] != 'false'
+
   class ArgumentError < ArgumentError
   end
 

lib/delivered/types.rb

@@ -13,6 +13,42 @@ def ===(value)
     end
   end
 
+  class EnumerableType
+    def initialize(type)
+      @type = type
+    end
+
+    def inspect = "Enumerable(#{@type.inspect})"
+
+    if Delivered::EXPENSIVE_TYPE_CHECKS
+      def ===(value)
+        Enumerable === value && value.all? { |item| @type === item }
+      end
+    else
+      def ===(value)
+        Enumerable === value && (value.empty? || @type === value.first)
+      end
+    end
+  end
+
+  class ArrayOfType
+    def initialize(type)
+      @type = type
+    end
+
+    def inspect = "ArrayOf(#{@type.inspect})"
+
+    if Delivered::EXPENSIVE_TYPE_CHECKS
+      def ===(value)
+        Array === value && value.all? { |item| @type === item }
+      end
+    else
+      def ===(value)
+        Array === value && (value.empty? || @type === value[0])
+      end
+    end
+  end
+
   class RangeOfType
     def initialize(type)
       @type = type
@@ -68,7 +104,9 @@ module Types
     module_function
 
     def Nilable(type = nil) = NilableType.new(type)
-    def RangeOf(type = nil) = RangeOfType.new(type)
+    def Enumerable(type = nil) = EnumerableType.new(type)
+    def ArrayOf(type) = ArrayOfType.new(type)
+    def RangeOf(type) = RangeOfType.new(type)
     def RespondTo(*methods) = RespondToType.new(*methods)
     def Any(*types) = AnyType.new(*types)
     def Boolean = BooleanType.new

test/delivered/types.rb

@@ -43,6 +43,39 @@
     end
   end
 
+  describe 'ArrayOf' do
+    it 'should be an Array of given type' do
+      assert T.ArrayOf(Integer) === [1, 2]
+      assert T.ArrayOf(Integer) === []
+    end
+
+    it 'raises when not an Array' do
+      expect { 1 => ^(T.ArrayOf(Integer)) }.to raise_exception NoMatchingPatternError
+    end
+
+    it 'raises when not an Array of given type' do
+      expect { [1] => ^(T.ArrayOf(String)) }.to raise_exception NoMatchingPatternError
+      expect { ['w', 1] => ^(T.ArrayOf(String)) }.to raise_exception NoMatchingPatternError
+    end
+  end
+
+  describe 'Enumerable' do
+    it 'should be an Enumerable of given type' do
+      assert T.Enumerable === []
+      assert T.Enumerable(Integer) === [1, 2]
+      assert T.Enumerable(Integer) === []
+    end
+
+    it 'raises when not an Enumerable' do
+      expect { 1 => ^(T.Enumerable(Integer)) }.to raise_exception NoMatchingPatternError
+    end
+
+    it 'raises when not an Enumerable of given type' do
+      expect { [1] => ^(T.Enumerable(String)) }.to raise_exception NoMatchingPatternError
+      expect { ['w', 1] => ^(T.Enumerable(String)) }.to raise_exception NoMatchingPatternError
+    end
+  end
+
   describe 'RangeOf' do
     it 'should be a Range of given type' do
       assert T.RangeOf(Integer) === (1..2)