Rename Vool to Sol

Simple is really the descriptive name for the layer
Sure, it is "virtual" but that is not as important as the fact that it is simple (or simplified)
Also objct (based really) is better, since orientated implies it is a little like that, but only orientated, not really it. Sol only has objects, nothing else
Just cause i was renaming anyway

lib/sol/if_statement.rb

@@ -0,0 +1,61 @@
+
+module Sol
+  class IfStatement < Statement
+
+    attr_reader :condition , :if_true , :if_false
+
+    def initialize( cond , if_true , if_false = nil)
+      @condition = cond
+      @if_true = if_true
+      @if_false = if_false
+    end
+
+    def to_slot( compiler )
+      true_label  = SlotMachine::Label.new( self , "true_label_#{object_id.to_s(16)}")
+      false_label = SlotMachine::Label.new( self , "false_label_#{object_id.to_s(16)}")
+      merge_label = SlotMachine::Label.new( self , "merge_label_#{object_id.to_s(16)}")
+
+      if @condition.is_a?(CallStatement)
+        head = @condition.to_slot(compiler)
+        head << check_slot(compiler , false_label)
+      else
+        head = check_slot(compiler , false_label)
+      end
+      head << true_label
+      head << if_true.to_slot(compiler)   if @if_true
+      head << SlotMachine::Jump.new(merge_label) if @if_false
+      head << false_label
+      head << if_false.to_slot(compiler)  if @if_false
+      head << merge_label                if @if_false
+      head
+    end
+
+    # create the slot lazily, so to_slot gets called first
+    def check_slot(compiler , false_label)
+      SlotMachine::TruthCheck.new(@condition.to_slot_definition(compiler) , false_label)
+    end
+
+    def each(&block)
+      block.call(condition)
+      @if_true.each(&block) if @if_true
+      @if_false.each(&block) if @if_false
+    end
+
+    def has_false?
+      @if_false != nil
+    end
+
+    def has_true?
+      @if_true != nil
+    end
+
+    def to_s(depth = 0)
+      parts =  "if (#{@condition.to_s(0)})\n"
+      parts += "  #{@if_true}\n" if @if_true
+      parts += "else\n" if(@if_false)
+      parts += "  #{@if_false}\n" if(@if_false)
+      parts += "end\n"
+      at_depth(depth , parts )
+    end
+  end
+end