From 655a14e36ef468fd16bd8ebac065f21608e49ace Mon Sep 17 00:00:00 2001
From: Gwenhael Le Moine <gwenhael.le.moine@gmail.com>
Date: Thu, 18 Nov 2021 15:58:59 +0100
Subject: [PATCH] implement SIGN

---
 lib/dictionary.rb          |  6 +++---
 lib/language/operations.rb | 31 +++++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/lib/dictionary.rb b/lib/dictionary.rb
index 01aa618..dec2a2e 100644
--- a/lib/dictionary.rb
+++ b/lib/dictionary.rb
@@ -39,13 +39,13 @@ module Rpn
       add( 'inv',     proc { |stack| Rpn::Core::Operations.inverse( stack ) } )
       add( '^',       proc { |stack| Rpn::Core::Operations.power( stack ) } )
       add( 'sqrt',    proc { |stack| Rpn::Core::Operations.sqrt( stack ) } )
-      add( 'sq',      proc { |stack| Rpn::Core.__todo( stack ) } ) # rpn_square
-      add( 'abs',     proc { |stack| Rpn::Core.__todo( stack ) } ) # absolute value
+      add( 'sq',      proc { |stack| Rpn::Core::Operations.sq( stack ) } )
+      add( 'abs',     proc { |stack| Rpn::Core::Operations.abs( stack ) } )
       add( 'dec',     proc { |stack| Rpn::Core.__todo( stack ) } ) # decimal representation
       add( 'hex',     proc { |stack| Rpn::Core.__todo( stack ) } ) # hexadecimal representation
       add( 'bin',     proc { |stack| Rpn::Core.__todo( stack ) } ) # binary representation
       add( 'base',    proc { |stack| Rpn::Core.__todo( stack ) } ) # arbitrary base representation
-      add( 'sign',    proc { |stack| Rpn::Core.__todo( stack ) } ) # 1 if number at stack level 1 is > 0, 0 if == 0, -1 if <= 0
+      add( 'sign',    proc { |stack| Rpn::Core::Operations.sign( stack ) } )
 
       # OPERATIONS ON REALS
       add( '%',       proc { |stack| Rpn::Core.__todo( stack ) } ) # percent
diff --git a/lib/language/operations.rb b/lib/language/operations.rb
index 1ed5de1..32bf0e1 100644
--- a/lib/language/operations.rb
+++ b/lib/language/operations.rb
@@ -96,6 +96,37 @@ module Rpn
         stack << { type: :numeric,
                    value: BigMath.sqrt( BigDecimal( args[0][:value] ), Rpn::Core.precision ) }
       end
+
+      # rpn_square
+      def sq( stack )
+        stack, args = Rpn::Core.stack_extract( stack, [%i[numeric]] )
+
+        stack << { type: :numeric,
+                   value: args[0][:value] * args[0][:value] }
+      end
+
+      # absolute value
+      def abs( stack )
+        stack, args = Rpn::Core.stack_extract( stack, [%i[numeric]] )
+
+        stack << { type: :numeric,
+                   value: args[0][:value].abs }
+      end
+
+      # 1 if number at stack level 1 is > 0, 0 if == 0, -1 if <= 0
+      def sign( stack )
+        stack, args = Rpn::Core.stack_extract( stack, [%i[numeric]] )
+        value = if args[0][:value].positive?
+                  1
+                elsif args[0][:value].negative?
+                  -1
+                else
+                  0
+                end
+
+        stack << { type: :numeric,
+                   value: value }
+      end
     end
   end
 end