From c30e4613859578b6fe3dbaeb81a24078e119a6b4 Mon Sep 17 00:00:00 2001
From: Torsten Ruger <torsten@villataika.fi>
Date: Sun, 8 Apr 2018 01:01:24 +0300
Subject: [PATCH] add operator to builder

just minus for now, easily extended
---
 lib/risc/builtin/word.rb  | 4 ++--
 lib/risc/risc_value.rb    | 7 +++++++
 test/risc/test_builder.rb | 6 ++++++
 3 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/lib/risc/builtin/word.rb b/lib/risc/builtin/word.rb
index 066af51a..f6de295f 100644
--- a/lib/risc/builtin/word.rb
+++ b/lib/risc/builtin/word.rb
@@ -69,11 +69,11 @@ module Risc
             space << Parfait.object_space
             space << space[:nil_object]
 
-            add Risc.op(source + "if method is nil", :- , space , typed_method )
+            space - typed_method
             if_zero exit_label
 
             name << typed_method[:name]
-            add Risc.op(source + " compare name with me", :- , name , word )
+            name - word
             if_not_zero false_label
 
             typed_method << typed_method[:binary]
diff --git a/lib/risc/risc_value.rb b/lib/risc/risc_value.rb
index 8c8c9ba5..8e9edd60 100644
--- a/lib/risc/risc_value.rb
+++ b/lib/risc/risc_value.rb
@@ -77,6 +77,13 @@ module Risc
       return ins
     end
 
+    def -( right )
+      raise "operators only on registers, not #{right.class}" unless right.is_a? RiscValue
+      op = Risc.op("#{self.type} - #{right.type}", :- , self , right )
+      builder.add(op) if builder
+      op
+    end
+    
     # just capture the values in an intermediary object (RValue)
     # The RValue then gets used in a RegToSlot ot SlotToReg, where
     # the values are unpacked to call Risc.reg_to_slot or Risc.slot_to_reg
diff --git a/test/risc/test_builder.rb b/test/risc/test_builder.rb
index 990a9dc0..f3e0248d 100644
--- a/test/risc/test_builder.rb
+++ b/test/risc/test_builder.rb
@@ -90,5 +90,11 @@ module Risc
       assert_equal Branch , ret.class
       assert_equal @label , ret.label
     end
+    def test_minus
+      op = @builder.build {space - typed_method}
+      assert_equal OperatorInstruction , op.class
+      assert_equal :- , op.operator
+      assert_equal :Space , op.left.type
+    end
   end
 end