start with block_compiler

as a copy of method_compiler
re-merge later, when we know what's needed

test/vool/blocks/test_assign.rb

@@ -0,0 +1,91 @@
+require_relative "../helper"
+
+module VoolBlocks
+  class TestAssignMom < MiniTest::Test
+    include MomCompile
+
+    def setup
+      Parfait.boot!
+      Risc::Builtin.boot_functions
+      @ins = compile_first_block( "local = 5")
+    end
+
+    def test_class_compiles
+      assert_equal Mom::SlotLoad , @ins.class , @ins
+    end
+    def pest_slot_is_set
+      assert @ins.left
+    end
+    def pest_slot_starts_at_message
+      assert_equal :message , @ins.left.known_object
+    end
+    def pest_slot_gets_self
+      assert_equal :frame , @ins.left.slots[0]
+    end
+    def pest_slot_assigns_to_local
+      assert_equal :main_local , @ins.left.slots[-1]
+    end
+    def pest_slot_assigns_something
+      assert @ins.right
+    end
+    def pest_slot_assigns_int
+      assert_equal Mom::IntegerConstant ,  @ins.right.known_object.class
+    end
+  end
+
+  #otherwise as above, but assigning instance, so should get a SlotLoad
+  class TestAssignMomInstanceToLocal < MiniTest::Test
+    include MomCompile
+    def setup
+      Parfait.boot!
+      @ins = compile_first_method( "@a = 5 ; local = @a")
+    end
+    def pest_class_compiles
+      assert_equal Mom::SlotLoad , @ins.next.class , @ins
+    end
+  end
+
+  #compiling to an argument should result in different second parameter in the slot array
+  class TestAssignToArg < MiniTest::Test
+    include MomCompile
+
+    def setup
+      Parfait.boot!
+      @ins = compile_first_method( "arg = 5")
+    end
+
+    def pest_class_compiles
+      assert_equal Mom::SlotLoad , @ins.class , @ins
+    end
+    def pest_slot_is_set
+      assert @ins.left
+    end
+    def pest_slot_starts_at_message
+      assert_equal :message , @ins.left.known_object
+    end
+    def pest_slot_gets_self
+      assert_equal :arguments , @ins.left.slots[0]
+    end
+    def pest_slot_assigns_to_local
+      assert_equal :arg , @ins.left.slots[-1]
+    end
+  end
+
+  class TestAssignMomToInstance < MiniTest::Test
+    include MomCompile
+    def setup
+      Parfait.boot!
+    end
+    def pest_assigns_const
+      @ins = compile_first_method( "@a = 5")
+      assert_equal Mom::SlotLoad , @ins.class , @ins
+      assert_equal Mom::IntegerConstant , @ins.right.known_object.class , @ins
+    end
+    def pest_assigns_move
+      @ins = compile_first_method( "@a = arg")
+      assert_equal Mom::SlotLoad , @ins.class , @ins
+      assert_equal Mom::SlotDefinition , @ins.right.class , @ins
+    end
+  end
+
+end