Refactor getter/property macros to work properly with Bool types

spec/std/object_spec.cr

@@ -35,6 +35,9 @@ private class TestObject
   def self.getter12_value=(@@getter12_value)
   end
 
+  @getter13_counter = 0
+  getter(getter13) { @getter13_counter += 1; false }
+
   setter setter1
   setter setter2 : Int32
   setter setter3 : Int32 = 3
@@ -58,6 +61,9 @@ private class TestObject
   property(property11) { 11 }
   property property12 : Int32 { 10 + 2 }
 
+  @property13_counter = 0
+  property(property13) { @property13_counter += 1; false }
+
   def initialize
     @getter1 = 1
     @getter2 = 2
@@ -205,6 +211,14 @@ describe Object do
       obj2 = TestObject.new
       obj2.getter12.should eq(24)
     end
+
+    # TODO: enable after 0.27.1
+    pending "defines lazy getter with block returning false" do
+      obj = TestObject.new
+      obj.@getter13_counter.should eq(0)
+      3.times { obj.getter13.should be_false }
+      obj.@getter13_counter.should eq(1)
+    end
   end
 
   describe "getter!" do
@@ -330,6 +344,14 @@ describe Object do
       obj.property12 = 13
       obj.property12.should eq(13)
     end
+
+    # TODO: enable after 0.27.1
+    pending "defines lazy property with block returning false" do
+      obj = TestObject.new
+      obj.@property13_counter.should eq(0)
+      3.times { obj.property13.should be_false }
+      obj.@property13_counter.should eq(1)
+    end
   end
 
   describe "property!" do

src/object.cr

@@ -339,7 +339,11 @@ class Object
     # ```
     # class Person
     #   def {{method_prefix}}birth_date
-    #     {{var_prefix}}birth_date ||= Time.now
+    #     if (_birth_date = {{var_prefix}}birth_date).nil?
+    #       {{var_prefix}}birth_date = Time.now
+    #     else
+    #       _birth_date
+    #     end
     #   end
     # end
     # ```
@@ -355,11 +359,19 @@ class Object
           {{var_prefix}}\{{name.var.id}} : \{{name.type}}?
 
           def {{method_prefix}}\{{name.var.id}}
-            {{var_prefix}}\{{name.var.id}} ||= \{{yield}}
+            if (_\{{name.var.id}} = {{var_prefix}}\{{name.var.id}}).nil?
+              {{var_prefix}}\{{name.var.id}} = \{{yield}}
+            else
+              _\{{name.var.id}}
+            end
           end
         \{% else %}
           def {{method_prefix}}\{{name.id}}
-            {{var_prefix}}\{{name.id}} ||= \{{yield}}
+            if (_\{{name.id}} = {{var_prefix}}\{{name.id}}).nil?
+              {{var_prefix}}\{{name.id}} = \{{yield}}
+            else
+              _\{{name.id}}
+            end
           end
         \{% end %}
       \{% else %}
@@ -790,7 +802,11 @@ class Object
     # ```
     # class Person
     #   def {{method_prefix}}birth_date
-    #     {{var_prefix}}birth_date ||= Time.now
+    #     if (_birth_date = {{var_prefix}}birth_date).nil?
+    #       {{var_prefix}}birth_date = Time.now
+    #     else
+    #       _birth_date
+    #     end
     #   end
     #
     #   def {{method_prefix}}birth_date=({{var_prefix}}birth_date)
@@ -811,11 +827,19 @@ class Object
           {{var_prefix}}\{{name.var.id}} : \{{name.type}}?
 
           def {{method_prefix}}\{{name.var.id}}
-            {{var_prefix}}\{{name.var.id}} ||= \{{yield}}
+            if (_\{{name.var.id}} = {{var_prefix}}\{{name.var.id}}).nil?
+              {{var_prefix}}\{{name.var.id}} = \{{yield}}
+            else
+              _\{{name.var.id}}
+            end
           end
         \{% else %}
           def {{method_prefix}}\{{name.id}}
-            {{var_prefix}}\{{name.id}} ||= \{{yield}}
+            if (_\{{name.id}} = {{var_prefix}}\{{name.id}}).nil?
+              {{var_prefix}}\{{name.id}} = \{{yield}}
+            else
+              _\{{name.id}}
+            end
           end
         \{% end %}
       \{% else %}