Updates to Avram Enums : ==, ===, enum constants (#566)

* Implements == on Avram Enums

* implements case equality operator on avram_enum

Also provides named constants which reflect the underlying enum values

* convert enum charm to struct

* add sad-path specs for avram enum

spec/type_extensions/enum_spec.cr

@@ -32,4 +32,44 @@ describe "Enum" do
     issue.status.to_s.should eq("Opened")
     issue.status.to_i.should eq(0)
   end
+
+  it "provides a working ==" do
+    Issue::Status.new(:closed).should eq(Issue::Status.new(:closed))
+    Issue::Status.new(:opened).should_not eq(Issue::Status.new(:closed))
+  end
+
+  it "provides enum-like constant values" do
+    Issue::Status::Closed.should eq(Issue::Status.new(:closed).enum)
+    Issue::Status.new(:closed).enum.should eq(Issue::Status::Closed)
+  end
+
+  it "implements case equality" do
+    case Issue::Status.new(:closed).value
+    when Issue::Status.new(:closed)
+      true
+    else
+      false
+    end.should be_true
+
+    case Issue::Status::Closed.value
+    when Issue::Status.new(:closed)
+      true
+    else
+      false
+    end.should be_true
+
+    case Issue::Status.new(:opened).value
+    when Issue::Status::Opened
+      true
+    else
+      false
+    end.should be_true
+
+    case Issue::Status::Opened.value
+    when Issue::Status::Opened
+      true
+    else
+      false
+    end.should be_true
+  end
 end

src/avram/charms/enum_extensions.cr

@@ -1,13 +1,26 @@
+macro redeclare_avram_enum(name)
+  {% for member in name.resolve.constants %}
+    {{ member }} = {{ name }}::{{ member }}
+  {% end %}
+end
+
 macro avram_enum(enum_name, &block)
-  enum Avram{{ enum_name }}
+  {% avram_enum = ("Avram" + enum_name.names.join("::")).id %}
+  enum {{ avram_enum }}
     {{ block.body }}
+
+    def ===(other : Int32)
+      value == other
+    end
   end
 
-  class {{ enum_name }}
+  struct {{ enum_name }}
     def self.adapter
       Lucky
     end
 
+    redeclare_avram_enum({{ avram_enum }})
+
     getter :enum
 
     # You may need to prefix with {{ @type }}
@@ -24,7 +37,7 @@ macro avram_enum(enum_name, &block)
       @enum = Avram{{ enum_name }}.from_value(enum_value.to_i)
     end
 
-    delegate to_s, to_i, to: @enum
+    delegate :===, to_s, to_i, to: @enum
 
     forward_missing_to @enum