diff --git a/src/spectator/dsl/values.cr b/src/spectator/dsl/values.cr
index 0e0aa7f..210a9c1 100644
--- a/src/spectator/dsl/values.cr
+++ b/src/spectator/dsl/values.cr
@@ -3,8 +3,13 @@ require "../lazy_wrapper"
 module Spectator::DSL
   # DSL methods for defining test values (subjects).
   module Values
+    # Defines a memoized getter.
+    # The *name* is the name of the getter method.
+    # The block is evaluated only on the first time the getter is used
+    # and the return value is saved for subsequent calls.
     macro let(name, &block)
       {% raise "Block required for 'let'" unless block %}
+      {% raise "Cannot use 'let' inside of a test block" if @def %}
 
       @%value = ::Spectator::LazyWrapper.new
 
@@ -12,49 +17,69 @@ module Spectator::DSL
         @%value.get {{block}}
       end
     end
-  end
 
-  macro let!(name, &block)
-      @%wrapper : ::Spectator::ValueWrapper?
+    # Defines a memoized getter.
+    # The *name* is the name of the getter method.
+    # The block is evaluated once before the example runs
+    # and the return value is saved.
+    macro let!(name, &block)
+      {% raise "Block required for 'let!'" unless block %}
+      {% raise "Cannot use 'let!' inside of a test block" if @def %}
 
-      def %wrapper
-        {{block.body}}
-      end
-
-      before_each do
-        @%wrapper = ::Spectator::TypedValueWrapper.new(%wrapper)
-      end
-
-      def {{name.id}}
-        @%wrapper.as(::Spectator::TypedValueWrapper(typeof(%wrapper))).value
-      end
+      let({{name}}) {{block}}
+      before_each { {{name.id}} }
     end
 
-  macro subject(&block)
-      {% if block.is_a?(Nop) %}
-        self.subject
-      {% else %}
-        let(:subject) {{block}}
+    # Explicitly defines the subject of the tests.
+    # Creates a memoized getter for the subject.
+    # The block is evaluated only the first time the subject is referenced
+    # and the return value is saved for subsequent calls.
+    macro subject(&block)
+      {% raise "Block required for 'subject'" unless block %}
+      {% raise "Cannot use 'subject' inside of a test block" if @def %}
+
+      let(subject) {{block}}
+    end
+
+    # Explicitly defines the subject of the tests.
+    # Creates a memoized getter for the subject.
+    # The subject can be referenced by using `subject` or *name*.
+    # The block is evaluated only the first time the subject is referenced
+    # and the return value is saved for subsequent calls.
+    macro subject(name, &block)
+      subject {{block}}
+
+      {% if name.id != :subject.id %}
+        def {{name.id}}
+          subject
+        end
       {% end %}
     end
 
-  macro subject(name, &block)
-      let({{name.id}}) {{block}}
+    # Explicitly defines the subject of the tests.
+    # Creates a memoized getter for the subject.
+    # The block is evaluated once before the example runs
+    # and the return value is saved for subsequent calls.
+    macro subject!(&block)
+      {% raise "Block required for 'subject!'" unless block %}
+      {% raise "Cannot use 'subject!' inside of a test block" if @def %}
 
-      def subject
-        {{name.id}}
-      end
+      let!(subject) {{block}}
     end
 
-  macro subject!(&block)
-      let!(:subject) {{block}}
-    end
+    # Explicitly defines the subject of the tests.
+    # Creates a memoized getter for the subject.
+    # The subject can be referenced by using `subject` or *name*.
+    # The block is evaluated once before the example runs
+    # and the return value is saved for subsequent calls.
+    macro subject!(name, &block)
+      subject! {{block}}
 
-  macro subject!(name, &block)
-      let!({{name.id}}) {{block}}
-
-      def subject
-        {{name.id}}
-      end
+      {% if name.id != :subject.id %}
+        def {{name.id}}
+          subject
+        end
+      {% end %}
     end
+  end
 end