From 21b090aa9f5883c45f58a8c7bc8340adb1f9f4ce Mon Sep 17 00:00:00 2001
From: Gwenhael Le Moine <gwenhael.le.moine@gmail.com>
Date: Wed, 8 Dec 2021 13:15:33 +0100
Subject: [PATCH] implement in pure Rpl

---
 lib/core/branch.rb | 13 +++++++----
 lib/core/stack.rb  | 58 +++++++++++++++++++++++++++++-----------------
 2 files changed, 45 insertions(+), 26 deletions(-)

diff --git a/lib/core/branch.rb b/lib/core/branch.rb
index 181625c..f175678 100644
--- a/lib/core/branch.rb
+++ b/lib/core/branch.rb
@@ -5,11 +5,6 @@ module Rpl
     module Core
       module_function
 
-      # similar to if-then-end, <test-instruction> <true-instruction> ift
-      def ift( stack, dictionary )
-        ifte( stack << { type: :word, value: 'nop' }, dictionary )
-      end
-
       # similar to if-then-else-end, <test-instruction> <true-instruction> <false-instruction> ifte
       def ifte( stack, dictionary )
         stack, args = Rpl::Lang::Core.stack_extract( stack, [%i[program word], %i[program word], %i[boolean]] )
@@ -18,6 +13,14 @@ module Rpl
 
         Rpl::Lang::Core.eval( stack, dictionary )
       end
+
+      # similar to if-then-end, <test-instruction> <true-instruction> ift
+      def ift( stack, dictionary )
+        stack << { value: '« « nop » ifte »',
+                   type: :program }
+
+        Rpl::Lang::Core.eval( stack, dictionary )
+      end
     end
   end
 end
diff --git a/lib/core/stack.rb b/lib/core/stack.rb
index 262bdf4..c7b86d0 100644
--- a/lib/core/stack.rb
+++ b/lib/core/stack.rb
@@ -14,16 +14,6 @@ module Rpl
         [stack, dictionary]
       end
 
-      # drop first stack entry
-      def drop( stack, dictionary )
-        dropn( stack << { type: :numeric, base: 10, value: 1 }, dictionary )
-      end
-
-      # drop 2 first stack entries
-      def drop2( stack, dictionary )
-        dropn( stack << { type: :numeric, base: 10, value: 2 }, dictionary )
-      end
-
       # drop n first stack entries
       def dropn( stack, dictionary )
         stack, args = Rpl::Lang::Core.stack_extract( stack, [%i[numeric]] )
@@ -46,16 +36,6 @@ module Rpl
         [stack, dictionary]
       end
 
-      # duplicate first stack entry
-      def dup( stack, dictionary )
-        dupn( stack << { type: :numeric, base: 10, value: 1 }, dictionary )
-      end
-
-      # duplicate 2 first stack entries
-      def dup2( stack, dictionary )
-        dupn( stack << { type: :numeric, base: 10, value: 2 }, dictionary )
-      end
-
       # duplicate n first stack entries
       def dupn( stack, dictionary )
         stack, args = Rpl::Lang::Core.stack_extract( stack, [%i[numeric]] )
@@ -129,9 +109,45 @@ module Rpl
         [stack, dictionary]
       end
 
+      # implemented in Rpl
       # push a copy of the element in stack level 2 onto the stack
       def over( stack, dictionary )
-        pick( stack << { type: :numeric, base: 10, value: 2 }, dictionary )
+        stack << { value: '« 2 pick »',
+                   type: :program }
+
+        Rpl::Lang::Core.eval( stack, dictionary )
+      end
+
+      # drop first stack entry
+      def drop( stack, dictionary )
+        stack << { value: '« 1 dropn »',
+                   type: :program }
+
+        Rpl::Lang::Core.eval( stack, dictionary )
+      end
+
+      # drop 2 first stack entries
+      def drop2( stack, dictionary )
+        stack << { value: '« 2 dropn »',
+                   type: :program }
+
+        Rpl::Lang::Core.eval( stack, dictionary )
+      end
+
+      # duplicate first stack entry
+      def dup( stack, dictionary )
+        stack << { value: '« 1 dupn »',
+                   type: :program }
+
+        Rpl::Lang::Core.eval( stack, dictionary )
+      end
+
+      # duplicate 2 first stack entries
+      def dup2( stack, dictionary )
+        stack << { value: '« 2 dupn »',
+                   type: :program }
+
+        Rpl::Lang::Core.eval( stack, dictionary )
       end
     end
   end