Support more literal types in use_yaml_discriminator

spec/std/yaml/serializable_spec.cr

@@ -347,6 +347,33 @@ class YAMLWithShape
   property shape : YAMLShape
 end
 
+enum YAMLVariableDiscriminatorEnumFoo
+  Foo = 4
+end
+
+class YAMLVariableDiscriminatorValueType
+  include YAML::Serializable
+
+  use_yaml_discriminator "type", {
+                                        0 => YAMLVariableDiscriminatorNumber,
+    "1"                                   => YAMLVariableDiscriminatorString,
+    true                                  => YAMLVariableDiscriminatorBool,
+    YAMLVariableDiscriminatorEnumFoo::Foo => YAMLVariableDiscriminatorEnum,
+  }
+end
+
+class YAMLVariableDiscriminatorNumber < YAMLVariableDiscriminatorValueType
+end
+
+class YAMLVariableDiscriminatorString < YAMLVariableDiscriminatorValueType
+end
+
+class YAMLVariableDiscriminatorBool < YAMLVariableDiscriminatorValueType
+end
+
+class YAMLVariableDiscriminatorEnum < YAMLVariableDiscriminatorValueType
+end
+
 describe "YAML::Serializable" do
   it "works with record" do
     YAMLAttrPoint.new(1, 2).to_yaml.should eq "---\nx: 1\ny: 2\n"
@@ -891,6 +918,20 @@ describe "YAML::Serializable" do
       point.x.should eq(1)
       point.y.should eq(2)
     end
+
+    it "deserializes with variable discriminator value type" do
+      object_number = YAMLVariableDiscriminatorValueType.from_yaml(%({"type": 0}))
+      object_number.should be_a(YAMLVariableDiscriminatorNumber)
+
+      object_string = YAMLVariableDiscriminatorValueType.from_yaml(%({"type": "1"}))
+      object_string.should be_a(YAMLVariableDiscriminatorString)
+
+      object_bool = YAMLVariableDiscriminatorValueType.from_yaml(%({"type": true}))
+      object_bool.should be_a(YAMLVariableDiscriminatorBool)
+
+      object_enum = YAMLVariableDiscriminatorValueType.from_yaml(%({"type": 4}))
+      object_enum.should be_a(YAMLVariableDiscriminatorEnum)
+    end
   end
 
   describe "namespaced classes" do

src/yaml/serialization.cr

@@ -401,6 +401,9 @@ module YAML
           discriminator_value = value.value
           case discriminator_value
           {% for key, value in mapping %}
+            {% if key.is_a?(Path) %}
+              {% key = key.resolve %}
+            {% end %}
             when {{key.id.stringify}}
               return {{value.id}}.new(ctx, node)
           {% end %}