From c885888f4a4af5129e89f02a3097fa5bd581613e Mon Sep 17 00:00:00 2001
From: Torsten Ruger <torsten@villataika.fi>
Date: Fri, 14 Apr 2017 10:52:23 +0300
Subject: [PATCH] start implementing return for constant

---
 lib/vool/statements/return_statement.rb |  9 +++++++
 test/vool/to_mom/test_local.rb          |  2 +-
 test/vool/to_mom/test_return.rb         | 31 +++++++++++++++++++++++++
 3 files changed, 41 insertions(+), 1 deletion(-)
 create mode 100644 test/vool/to_mom/test_return.rb

diff --git a/lib/vool/statements/return_statement.rb b/lib/vool/statements/return_statement.rb
index 75bc5e89..5f33895e 100644
--- a/lib/vool/statements/return_statement.rb
+++ b/lib/vool/statements/return_statement.rb
@@ -10,5 +10,14 @@ module Vool
       @return_value.collect(arr)
       super
     end
+
+    # To return form a method in mom instructions we need to do three things:
+    # - store the given return value, this is a SlotMove / SlotConstant
+    # - restore the previous message
+    # - jump to the return address
+    def to_mom( method )
+      [Mom::SlotConstant.new([:message , :return_value] , @return_value)]
+    end
+
   end
 end
diff --git a/test/vool/to_mom/test_local.rb b/test/vool/to_mom/test_local.rb
index 599afb3f..46d06801 100644
--- a/test/vool/to_mom/test_local.rb
+++ b/test/vool/to_mom/test_local.rb
@@ -18,7 +18,7 @@ module Vool
     def test_slot_starts_at_message
       assert_equal :message , @stats.first.left[0]
     end
-    def test_slot_gets_self
+    def test_slot_gets_frame
       assert_equal :frame , @stats.first.left[1]
     end
     def test_slot_assigns_to_local
diff --git a/test/vool/to_mom/test_return.rb b/test/vool/to_mom/test_return.rb
new file mode 100644
index 00000000..27b07756
--- /dev/null
+++ b/test/vool/to_mom/test_return.rb
@@ -0,0 +1,31 @@
+require_relative "helper"
+
+module Vool
+  class TestReturnMom < MiniTest::Test
+    include MomCompile
+
+    def setup
+      Risc.machine.boot
+      @stats = compile_first_method( "return 5").first
+    end
+
+    def test_class_compiles
+      assert_equal Mom::SlotConstant , @stats.first.class , @stats
+    end
+    def test_slot_is_set
+      assert @stats.first.left
+    end
+    def test_slot_starts_at_message
+      assert_equal :message , @stats.first.left[0]
+    end
+    def test_slot_gets_self
+      assert_equal :return_value , @stats.first.left[1]
+    end
+    def test_slot_assigns_something
+      assert @stats.first.right
+    end
+    def test_slot_assigns_int
+      assert_equal IntegerStatement ,  @stats.first.right.class
+    end
+  end
+end