introduce constant class and add block to compile signature(wip, work in progress)

lib/vm/constants.rb

@@ -0,0 +1,51 @@
+module Vm
+  
+  # constants are the stuff that you embedd in the program as numbers or strings. 
+  # Another way to think about them is as Operands, they have no seperate "identity"
+  # and usually end up embedded in the instructions. ie your basic foo + 4 will encode
+  # the 4 in the instruction opcode. The 4 is not accessible anywhere else.
+  # When it should be usable in other forms, the constant must become a Value first 
+  class Constant < Value
+    
+  end
+
+
+  class IntegerConstant < Constant
+    def init int
+      @integer = int
+    end
+    attr_reader :integer
+  end
+
+  # The name really says it all.
+  # The only interesting thing is storage.
+  # Currently string are stored "inline" , ie in the code segment. 
+  # Mainly because that works an i aint no elf expert.
+  
+  class StringConstant < Constant
+    attr_reader :string
+    # currently aligned to 4 (ie padded with 0) and off course 0 at the end
+    def initialize str
+      length = str.length 
+      # rounding up to the next 4 (always adding one for zero pad)
+      pad =  ((length / 4 ) + 1 ) * 4 - length
+      raise "#{pad} #{self}" unless pad >= 1
+      @string = str + "\x00" * pad 
+    end
+
+    def load reg_num
+      Machine.instance.string_load self , reg_num
+    end
+
+    # the strings length plus padding
+    def length
+      string.length
+    end
+    
+    # just writing the string
+    def assemble(io)
+      io << string
+    end
+  end
+  
+end