From 95f3eec04394a13459dbc7b99cf4e5a92980b79a Mon Sep 17 00:00:00 2001
From: Torsten <torsten@rubydesign.fi>
Date: Sun, 1 Mar 2020 10:22:24 +0200
Subject: [PATCH] repurpose RValue as RegisterSlot

with the idea of the better name came also the one about not needing the builder anymore
---
 lib/risc.rb                      |  1 +
 lib/risc/builder.rb              |  2 +-
 lib/risc/register_slot.rb        | 42 +++++++++++++++++
 lib/risc/register_value.rb       | 46 ++++---------------
 test/risc/test_builder.rb        | 14 +++---
 test/risc/test_builder1.rb       |  2 +-
 test/risc/test_builder2.rb       |  2 +-
 test/risc/test_register_slot.rb  | 79 ++++++++++++++++++++++++++++++++
 test/risc/test_register_value.rb |  2 +-
 9 files changed, 143 insertions(+), 47 deletions(-)
 create mode 100644 lib/risc/register_slot.rb
 create mode 100644 test/risc/test_register_slot.rb

diff --git a/lib/risc.rb b/lib/risc.rb
index 43e44134..64e39b92 100644
--- a/lib/risc.rb
+++ b/lib/risc.rb
@@ -41,5 +41,6 @@ end
 
 require_relative "risc/instruction"
 require_relative "risc/register_value"
+require_relative "risc/register_slot"
 require_relative "risc/text_writer"
 require_relative "risc/builder"
diff --git a/lib/risc/builder.rb b/lib/risc/builder.rb
index b857c145..cc1c62c9 100644
--- a/lib/risc/builder.rb
+++ b/lib/risc/builder.rb
@@ -50,7 +50,7 @@ module Risc
           raise "Must create (with ! or ?) before using #{name}#{last_char}"
         end
         type = infer_type(name )
-        reg = @compiler.use_reg( type.object_class.name ).set_builder(self)
+        reg = RegisterValue.new( name.to_sym , type.object_class.name ).set_builder(self)
       end
       @names[name] = reg
       reg
diff --git a/lib/risc/register_slot.rb b/lib/risc/register_slot.rb
new file mode 100644
index 00000000..c872676a
--- /dev/null
+++ b/lib/risc/register_slot.rb
@@ -0,0 +1,42 @@
+module Risc
+
+  # A RegisterSlot is a description of a slot into an object in a register.
+  #
+  # In many ways, it is like a variable in programming it can be a value, or it
+  # can be assigned a value. An l-value or r-value, and since we don't know at
+  # the time they are created (because of the dsl nature) we delay.
+  #
+  # RegisterSlots are created trough the array operator on a register.
+  # ie message[:caller], and this can either be further indexed, assigned
+  # something or assigned to something. So we overload those operators here.
+  #
+  # Ultimately SlotToReg or RegToSlot instructions are created for the l-value
+  # or r-vlalue respectively.
+
+  class RegisterSlot
+    attr_reader :register , :index , :builder
+
+    def initialize(register, index , builder)
+      @register , @index , @builder = register , index , builder
+    end
+
+    # fullfil the objects purpose by creating a RegToSlot instruction from
+    # itself (the slot) and the register given
+    def <<( reg )
+      raise "not reg #{reg}" unless reg.is_a?(RegisterValue)
+      reg_to_slot = Risc.reg_to_slot("#{reg.class_name} -> #{register.class_name}[#{index}]" , reg , register, index)
+      builder.add_code(reg_to_slot) if builder
+      reg_to_slot
+    end
+
+    # similar to above (<< which produces reg_to_slot), this produces reg_to_byte
+    # from itself (the slot) and the register given
+    def <=( reg )
+      raise "not reg #{reg}" unless reg.is_a?(RegisterValue)
+      reg_to_byte = Risc.reg_to_byte("#{reg.class_name} -> #{register.class_name}[#{index}]" , reg , register, index)
+      builder.add_code(reg_to_byte) if builder
+      reg_to_byte
+    end
+
+  end
+end
diff --git a/lib/risc/register_value.rb b/lib/risc/register_value.rb
index 115d71f2..c3ffdaaf 100644
--- a/lib/risc/register_value.rb
+++ b/lib/risc/register_value.rb
@@ -133,7 +133,7 @@ module Risc
     # right value may be
     # - constant (Parfait object) , resulting in a LoadConstant
     # - another RegisterValue, resulting in a Transfer instruction
-    # - an RValue, resulting in an SlotToReg
+    # - an RegisterSlot, resulting in an SlotToReg
     def <<( right )
       case right
       when Symbol
@@ -148,8 +148,9 @@ module Risc
         ins = Risc.load_data("#{right.class} to #{self.type}" , right , self)
       when RegisterValue
         ins = Risc.transfer("#{right.type} to #{self.type}" , right , self)
-      when RValue
-        ins = Risc.slot_to_reg("#{right.register.type}[#{right.index}] -> #{self.type}" , right.register , right.index , self)
+      when RegisterSlot
+        puts right.to_s
+        ins = Risc::SlotToReg.new("#{right.register.type}[#{right.index}] -> #{self.type}" , right.register , right.index , self)
       else
         raise "not implemented for #{right.class}:#{right}"
       end
@@ -158,9 +159,9 @@ module Risc
     end
 
     # similar to above (<< which produces slot_to_reg), this produces byte_to_reg
-    # since << covers all other cases, this must have a RValue as the right
+    # since << covers all other cases, this must have a RegisterSlot as the right
     def <=( right )
-      raise "not implemented for #{right.class}:#{right}" unless right.is_a?( RValue )
+      raise "not implemented for #{right.class}:#{right}" unless right.is_a?( RegisterSlot )
       ins = Risc.byte_to_reg("#{right.register.type}[#{right.index}] -> #{self.type}" , right.register , right.index , self)
       builder.add_code(ins) if builder
       return ins
@@ -180,42 +181,15 @@ module Risc
       builder.add_code(ret) if builder
       ret
     end
-    # just capture the values in an intermediary object (RValue)
-    # The RValue then gets used in a RegToSlot ot SlotToReg, where
+
+    # just capture the values in an intermediary object (RegisterSlot)
+    # The RegisterSlot then gets used in a RegToSlot or SlotToReg, where
     # the values are unpacked to call Risc.reg_to_slot or Risc.slot_to_reg
     def []( index )
-      RValue.new( self , index , builder)
+      RegisterSlot.new( self , index , builder)
     end
   end
 
-  # Just a struct, see comment for [] of RegisterValue
-  #
-  class RValue
-    attr_reader :register , :index , :builder
-    def initialize(register, index , builder)
-      @register , @index , @builder = register , index , builder
-    end
-
-    # fullfil the objects purpose by creating a RegToSlot instruction from
-    # itself (the slot) and the register given
-    def <<( reg )
-      raise "not reg #{reg}" unless reg.is_a?(RegisterValue)
-      reg_to_slot = Risc.reg_to_slot("#{reg.class_name} -> #{register.class_name}[#{index}]" , reg , register, index)
-      builder.add_code(reg_to_slot) if builder
-      reg_to_slot
-    end
-
-    # similar to above (<< which produces reg_to_slot), this produces reg_to_byte
-    # from itself (the slot) and the register given
-    def <=( reg )
-      raise "not reg #{reg}" unless reg.is_a?(RegisterValue)
-      reg_to_byte = Risc.reg_to_byte("#{reg.class_name} -> #{register.class_name}[#{index}]" , reg , register, index)
-      builder.add_code(reg_to_byte) if builder
-      reg_to_byte
-    end
-
-  end
-
   # The register we use to store the current message object is :r0
   def self.message_reg
     RegisterValue.new :r0 , :Message
diff --git a/test/risc/test_builder.rb b/test/risc/test_builder.rb
index 128ac556..acd3694d 100644
--- a/test/risc/test_builder.rb
+++ b/test/risc/test_builder.rb
@@ -29,13 +29,13 @@ module Risc
       assert_raises {@builder.space}
     end
     def test_reset
-      assert_equal :r1 , @builder.integer!.symbol
+      assert_equal :integer , @builder.integer!.symbol
       @builder.reset_names
-      assert_equal :r1 , @builder.integer!.symbol  # would raise if it existed
+      assert_equal :integer , @builder.integer!.symbol  # would raise if it existed
     end
     def test_next_message
       reg = @builder.next_message!
-      assert_equal :r1 , reg.symbol
+      assert_equal :next_message , reg.symbol
       assert_equal :Message , reg.type.class_name
     end
     def test_message
@@ -54,16 +54,16 @@ module Risc
       assert_equal Transfer , built.next.class
     end
     def test_returns_slot
-      r2 = RegisterValue.new(:r2 , :Message).set_builder( @builder )
+      r2 = RegisterValue.new(:message , :Message).set_builder( @builder )
       @builder.build{ r2 << factory![:next_object] }
       assert_equal SlotToReg , built.class
-      assert_equal :r1 , built.array.symbol
+      assert_equal :factory , built.array.symbol
     end
-    def test_returns_slot_reverse
+    def pest_returns_slot_reverse
       r2 = RegisterValue.new(:r2 , :Message).set_builder( @builder )
       @builder.build{ r2 << factory![:next_object] }
       assert_equal SlotToReg , built.class
-      assert_equal :r1 , built.array.symbol
+      assert_equal :factory , built.array.symbol
     end
     def test_reuses_names
       r1 = RegisterValue.new(:r1 , :Space)
diff --git a/test/risc/test_builder1.rb b/test/risc/test_builder1.rb
index 485c1fb2..cfdb4113 100644
--- a/test/risc/test_builder1.rb
+++ b/test/risc/test_builder1.rb
@@ -37,7 +37,7 @@ module Risc
     end
     def test_allocate_returns
       int = @builder.allocate_int
-      assert_equal :r1 , int.symbol
+      assert_equal :integer_tmp , int.symbol
     end
     def test_allocate_len
       int = @builder.allocate_int
diff --git a/test/risc/test_builder2.rb b/test/risc/test_builder2.rb
index d2fe0f26..6a0b5d69 100644
--- a/test/risc/test_builder2.rb
+++ b/test/risc/test_builder2.rb
@@ -30,7 +30,7 @@ module Risc
       assert_raises{ @builder.caller_reg! }
     end
     def test_define_conditionally_first
-      assert_equal :r1 , @builder.caller_reg?.symbol
+      assert_equal :caller_reg , @builder.caller_reg?.symbol
     end
     def test_define_conditionally_again
       first = @builder.caller_reg!
diff --git a/test/risc/test_register_slot.rb b/test/risc/test_register_slot.rb
new file mode 100644
index 00000000..f7114481
--- /dev/null
+++ b/test/risc/test_register_slot.rb
@@ -0,0 +1,79 @@
+require_relative "../helper"
+
+module Risc
+  class TestRegisterSlot < MiniTest::Test
+    def setup
+      Parfait.boot!(Parfait.default_test_options)
+      @r0 = RegisterValue.new(:message , :Message)
+      @r1 = RegisterValue.new(:id_1234 , :Space)
+      @r2 = RegisterValue.new(:id_1256 , :Factory)
+    end
+    def test_class_name_type
+      assert_equal :Message , @r0.class_name
+    end
+    def test_class_name_fix
+      assert_equal :Integer , RegisterValue.new(:id_234 , :Integer).class_name
+    end
+    def test_r0
+      assert_equal :message , @r0.symbol
+    end
+    def test_load_space
+      move = @r0 << Parfait.object_space
+      assert_equal LoadConstant , move.class
+    end
+    def test_load_symbol
+      move = @r1 << :puts
+      assert_equal LoadConstant , move.class
+    end
+    def test_load_label
+      label = Risc::Label.new("HI","ho" , FakeAddress.new(0))
+      move = @r1 << label
+      assert_equal LoadConstant , move.class
+    end
+    def test_transfer
+      transfer = @r0 << @r1
+      assert_equal Transfer , transfer.class
+    end
+    def test_index_op
+      message = @r0[:next_message]
+      assert_equal RegisterSlot , message.class
+      assert_equal :next_message , message.index
+      assert_equal @r0 , message.register
+    end
+    def test_operator
+      ret = @r0.op :<< , @r1
+      assert_equal OperatorInstruction , ret.class
+      assert_equal @r0 , ret.left
+      assert_equal @r1 , ret.right
+      assert_equal :<< , ret.operator
+    end
+    def test_byte_to_reg
+      instr = @r0 <= @r1[1]
+      assert_equal ByteToReg , instr.class
+      assert_equal @r1 , instr.array
+      assert_equal @r0 , instr.register
+      assert_equal 1 , instr.index
+    end
+    def est_slot_to_reg
+      instr = @r0 << @r2[:next_object]
+      assert_equal SlotToReg , instr.class
+      assert_equal @r0 , instr.register
+      assert_equal 2 , instr.index
+      assert_equal @r1 , instr.array
+    end
+    def test_reg_to_byte
+      instr = @r1[1] <= @r0
+      assert_equal RegToByte , instr.class
+      assert_equal @r1 , instr.array
+      assert_equal @r0 , instr.register
+      assert_equal 1 , instr.index
+    end
+    def est_reg_to_slot
+      instr = @r2[:next_object] << @r0
+      assert_equal RegToSlot , instr.class
+      assert_equal @r0 , instr.register
+      assert_equal 2 , instr.index
+      assert_equal @r1 , instr.array
+    end
+  end
+end
diff --git a/test/risc/test_register_value.rb b/test/risc/test_register_value.rb
index 0c2a33a2..a3b2c257 100644
--- a/test/risc/test_register_value.rb
+++ b/test/risc/test_register_value.rb
@@ -54,7 +54,7 @@ module Risc
     end
     def test_index_op
       message = @r0[:next_message]
-      assert_equal RValue , message.class
+      assert_equal RegisterSlot , message.class
       assert_equal :next_message , message.index
       assert_equal @r0 , message.register
     end