Add support for unless

ifs without a true branch would crash before
Somewhat more verbose but unified

.reek

@@ -13,13 +13,15 @@ FeatureEnvy:
     - "Arm::Translator"
     - "Vm::ToCode"
 TooManyMethods:
+  max_methods: 30
   exclude:
     - "Vool::Compiler"
     - "RubyX::RubyCompiler"
+    - "Ruby::RubyCompiler"
     - "Risc::Interpreter"
     - "Risc::TextWriter"
     - "Arm::Translator"
-    - "Vm::ToCode"
+    - "Util::List"
 UtilityFunction:
   exclude:
     - "Vool::Compiler"

.travis.yml

@@ -1,10 +1,11 @@
+before_install:
+  - sudo apt-get install -y qemu
 language: ruby
-sudo: false
 before_install: gem install bundler --version '2.0.1'
 script:
   - ruby test/test_all.rb
   - bundle exec codeclimate-test-reporter
 rvm:
-  - 2.4.5
-  - 2.5.3
-  - 2.6.1
+  - 2.4.6
+  - 2.5.5
+  - 2.6.3

lib/vool/if_statement.rb

@@ -11,36 +11,23 @@ module Vool
     end
 
     def to_mom( compiler )
-      if_false ? full_if(compiler) : simple_if(compiler)
-    end
-
-    def simple_if(compiler)
-      true_label  = Mom::Label.new( self,"true_label_#{object_id.to_s(16)}")
-      merge_label = Mom::Label.new( self,"merge_label_#{object_id.to_s(16)}")
-
-      head = Mom::TruthCheck.new(condition.slot_definition(compiler) , merge_label)
-      head << true_label
-      head << if_true.to_mom(compiler)
-      head << merge_label
-    end
-
-    def full_if(compiler)
       true_label  = Mom::Label.new( self , "true_label_#{object_id.to_s(16)}")
       false_label = Mom::Label.new( self , "false_label_#{object_id.to_s(16)}")
       merge_label = Mom::Label.new( self , "merge_label_#{object_id.to_s(16)}")
 
       head = Mom::TruthCheck.new(condition.slot_definition(compiler) , false_label)
       head << true_label
-      head << if_true.to_mom(compiler)
-      head << Mom::Jump.new(merge_label)
+      head << if_true.to_mom(compiler)   if @if_true
+      head << Mom::Jump.new(merge_label) if @if_false
       head << false_label
-      head << if_false.to_mom(compiler)
-      head << merge_label
+      head << if_false.to_mom(compiler)  if @if_false
+      head << merge_label                if @if_false
+      head
     end
 
     def each(&block)
       block.call(condition)
-      @if_true.each(&block)
+      @if_true.each(&block) if @if_true
       @if_false.each(&block) if @if_false
     end
 

test/mom/test_if_no_else.rb

@@ -24,7 +24,6 @@ module Risc
       produced = produce_body
       check = produced.next(4)
       assert_equal IsZero , check.class
-      assert check.label.name.start_with?("merge_label") , check.label.name
     end
     def test_false_label
       produced = produce_body

test/mom/test_if_no_if.rb

@@ -0,0 +1,56 @@
+require_relative "helper"
+
+module Risc
+  class TestIfNoIf < MiniTest::Test
+    include Statements
+
+    def setup
+      super
+      @input = "unless(@a) ; arg = 5 ; end"
+      @expect = [SlotToReg, SlotToReg, LoadConstant, OperatorInstruction, IsZero, #4
+                 LoadConstant, OperatorInstruction, IsZero, Label, Branch, #9
+                 Label, LoadConstant, SlotToReg, RegToSlot, Label] #14
+   end
+
+    def test_if_instructions
+      assert_nil msg = check_nil , msg
+    end
+
+    def test_false_load
+      produced = produce_body
+      assert_equal Parfait::FalseClass , produced.next(2).constant.class
+    end
+    def test_isnotzero
+      produced = produce_body
+      check = produced.next(4)
+      assert_equal IsZero , check.class
+      assert check.label.name.start_with?("false_") , check.label.name
+    end
+    def test_false_label
+      produced = produce_body
+      assert_equal Label , produced.next(10).class
+    end
+    def test_false_check
+      produced = produce_body
+      assert_equal produced.next(10).name , produced.next(4).label.name
+    end
+    def test_nil_load
+      produced = produce_body
+      assert_equal Parfait::NilClass , produced.next(5).constant.class
+    end
+    def est_nil_check
+      produced = produce_body
+      assert_equal Label , produced.next(4).label.class
+      assert_equal produced.next(12) , produced.next(4).label
+    end
+    def test_true_label
+      produced = produce_body
+      assert produced.next(8).name.start_with?("true_label")
+    end
+    def test_merge_label
+      produced = produce_body
+      assert produced.next(14).name.start_with?("merge_label")
+    end
+
+  end
+end

test/vool/test_if_no_if.rb

@@ -0,0 +1,31 @@
+
+require_relative "helper"
+
+module Vool
+  class TestIfNoIf < MiniTest::Test
+    include VoolCompile
+
+    def setup
+      Parfait.boot!(Parfait.default_test_options)
+      @compiler = compile_first_method( "unless(@a) ; @a = 5 ; end")
+      @ins = @compiler.mom_instructions.next
+    end
+
+    def test_condition_compiles_to_check
+      assert_equal TruthCheck , @ins.class , @ins
+    end
+    def test_condition_is_slot
+      assert_equal SlotDefinition , @ins.condition.class , @ins
+    end
+    def test_label_after_check
+      assert_equal Label , @ins.next.class , @ins
+    end
+    def test_label_last
+      assert_equal Label , @ins.last.class , @ins
+    end
+    def test_array
+      check_array  [TruthCheck, Label, Jump, Label, SlotLoad ,
+                    Label, Label, ReturnSequence, Label] , @ins
+    end
+  end
+end