From 4c7e50f9328aca4e294b41fce0832bf6ac4a939a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Felix=20Bu=CC=88nemann?= <buenemann@louis.info>
Date: Sat, 19 Dec 2015 19:40:46 +0100
Subject: Implement CASE Conditional Expression

---
 lib/arel/visitors/depth_first.rb | 10 +++++++++-
 lib/arel/visitors/to_sql.rb      | 29 +++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+), 1 deletion(-)

(limited to 'lib/arel/visitors')

diff --git a/lib/arel/visitors/depth_first.rb b/lib/arel/visitors/depth_first.rb
index 22704dd038..2f71455580 100644
--- a/lib/arel/visitors/depth_first.rb
+++ b/lib/arel/visitors/depth_first.rb
@@ -16,6 +16,7 @@ module Arel
       def unary o
         visit o.expr
       end
+      alias :visit_Arel_Nodes_Else              :unary
       alias :visit_Arel_Nodes_Group             :unary
       alias :visit_Arel_Nodes_Grouping          :unary
       alias :visit_Arel_Nodes_Having            :unary
@@ -53,6 +54,12 @@ module Arel
         visit o.distinct
       end
 
+      def visit_Arel_Nodes_Case o
+        visit o.case
+        visit o.conditions
+        visit o.default
+      end
+
       def nary o
         o.children.each { |child| visit child}
       end
@@ -86,8 +93,9 @@ module Arel
       alias :visit_Arel_Nodes_Regexp             :binary
       alias :visit_Arel_Nodes_RightOuterJoin     :binary
       alias :visit_Arel_Nodes_TableAlias         :binary
-      alias :visit_Arel_Nodes_Values             :binary
       alias :visit_Arel_Nodes_Union              :binary
+      alias :visit_Arel_Nodes_Values             :binary
+      alias :visit_Arel_Nodes_When               :binary
 
       def visit_Arel_Nodes_StringJoin o
         visit o.left
diff --git a/lib/arel/visitors/to_sql.rb b/lib/arel/visitors/to_sql.rb
index ce1fdf80ce..598bf2d984 100644
--- a/lib/arel/visitors/to_sql.rb
+++ b/lib/arel/visitors/to_sql.rb
@@ -708,6 +708,35 @@ module Arel
         visit o.right, collector
       end
 
+      def visit_Arel_Nodes_Case o, collector
+        collector << "CASE "
+        if o.case
+          visit o.case, collector
+          collector << " "
+        end
+        o.conditions.each do |condition|
+          visit condition, collector
+          collector << " "
+        end
+        if o.default
+          visit o.default, collector
+          collector << " "
+        end
+        collector << "END"
+      end
+
+      def visit_Arel_Nodes_When o, collector
+        collector << "WHEN "
+        visit o.left, collector
+        collector << " THEN "
+        visit o.right, collector
+      end
+
+      def visit_Arel_Nodes_Else o, collector
+        collector << "ELSE "
+        visit o.expr, collector
+      end
+
       def visit_Arel_Nodes_UnqualifiedColumn o, collector
         collector << "#{quote_column_name o.name}"
         collector
-- 
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