feat: add type, add == for comparison

Author: initdc

.rubocop.yml

@@ -7,6 +7,9 @@ plugins:
 Metrics/BlockLength:
   Enabled: false
 
+Metrics/MethodLength:
+  Enabled: false
+
 RSpec/MultipleExpectations:
   Enabled: false
 
@@ -15,4 +18,3 @@ RSpec/ExampleLength:
 
 RSpec/MissingExpectationTargetMethod:
   Enabled: false
-

lib/rs/option.rb

@@ -8,6 +8,7 @@ module Rs
   module Option
     class ArgumentError < StandardError; end
     class UnwrapNone < StandardError; end
+    class TypeError < StandardError; end
 
     def some?
       @some
@@ -64,20 +65,50 @@ def unwrap_or_else(&block)
 class Some
   include Rs::Option
 
-  def initialize(value)
+  attr_reader :type
+  attr_reader :some
+
+  private attr_reader :value
+
+  def initialize(value, type: nil)
     if value == nil
       raise(Rs::Option::ArgumentError, "Some value cannot be nil")
     end
 
-    @value = value
+    if type
+      if value.class != type
+        raise(Rs::Option::TypeError, "Value type #{value.class} does not match #{type}")
+      end
+
+      @type = type
+    else
+      @type = value.class
+    end
+
     @some = true
+    @value = value
+  end
+
+  def ==(other)
+    other.is_a?(Some) && @type == other.type && @value == other.unwrap
   end
 end
 
 class None
   include Rs::Option
 
+  attr_reader :type
+  attr_reader :some
+
+  private attr_reader :value
+
   def initialize
+    @type = NilClass
     @some = false
+    @value = nil
+  end
+
+  def ==(other)
+    other.is_a? None
   end
 end

lib/rs/result.rb

@@ -11,6 +11,7 @@ module Result
     class ArgumentError < StandardError; end
     class UnwrapOnErr < StandardError; end
     class UnwrapErrOnOk < StandardError; end
+    class TypeError < StandardError; end
 
     def ok?
       @ok
@@ -90,20 +91,60 @@ def unwrap_err
 
 class Ok
   include Rs::Result
-  def initialize(value)
+
+  attr_reader :type
+  attr_reader :ok
+
+  private attr_reader :value
+
+  def initialize(value, type: nil)
     if value == nil
       raise(Rs::Result::ArgumentError, "Ok value cannot be nil")
     end
 
-    @value = value
+    if type
+      if value.class != type
+        raise(Rs::Result::TypeError, "Value type #{value.class} does not match #{type}")
+      end
+
+      @type = type
+    else
+      @type = value.class
+    end
+
     @ok = true
+    @value = value
+  end
+
+  def ==(other)
+    other.is_a?(Ok) && @type == other.type && @value == other.unwrap
   end
 end
 
 class Err
   include Rs::Result
-  def initialize(error)
-    @value = error
+
+  attr_reader :type
+  attr_reader :ok
+
+  private attr_reader :value
+
+  def initialize(error, type: nil)
+    if type
+      if error.class != type
+        raise(Rs::Result::TypeError, "Error type #{error.class} does not match #{type}")
+      end
+
+      @type = type
+    else
+      @type = error.class
+    end
+
     @ok = false
+    @value = error
+  end
+
+  def ==(other)
+    other.is_a?(Err) && @type == other.type && @value == other.unwrap_err
   end
 end

spec/rs/option_spec.rb

@@ -85,4 +85,37 @@
     expect(x.unwrap_or).to be_nil
     expect(y.unwrap_or).to eq 12
   end
+
+  it "pattern_matching" do
+    def divide(numerator, denominator)
+      if denominator == 0
+        None.new
+      else
+        Some.new(numerator / denominator)
+      end
+    end
+
+    result = divide(3, 1)
+    case result
+    when Some
+      x = result.unwrap
+    else
+      x = "Cannot divide by 0"
+    end
+    expect(x).to eq 3
+  end
+
+  it "type ==" do
+    a = Some.new(1)
+    b = Some.new(1.0)
+    c = Some.new(1.0, type: Float)
+    d = Some.new("a")
+    e = None.new
+
+    expect(a == b).to be false
+    expect(a == c).to be false
+    expect(b == c).to be true
+    expect(a == d).to be false
+    expect(a == e).to be false
+  end
 end

spec/rs/result_spec.rb

@@ -133,4 +133,28 @@ def parse_year(str)
     expect(Ok.new(2).unwrap_or_else { |x| x.size }).to eq 2
     expect(Err.new("foo").unwrap_or_else { |x| x.size }).to eq 3
   end
+
+  it "type ==" do
+    a = Ok.new(1)
+    b = Ok.new(1.0)
+    c = Ok.new(1.0, type: Float)
+    d = Ok.new("a")
+
+    e = Err.new(1)
+    f = Err.new(1.0)
+    g = Err.new(1.0, type: Float)
+    h = Err.new("a")
+    i = Err.new(nil)
+
+    expect(a == b).to be false
+    expect(a == c).to be false
+    expect(b == c).to be true
+    expect(a == d).to be false
+
+    expect(e == f).to be false
+    expect(e == g).to be false
+    expect(f == g).to be true
+    expect(e == h).to be false
+    expect(e == i).to be false
+  end
 end