Added feed aggregation module.

Redesigned the CMS_BLOCK system,
   - added condition attribute. It can be set via configuration file
     with
     [blocks]
      {blockid}.region={region_name}
      {blockid}.conditions[]=is_front
      {blockid}.conditions[]=path:location-path/foo/bar
   - For backward compatibility, the CMS will check only conditions for block name prefixed by "?".
Improved the configuration library to support list and table properties.
Updated theme for now, to include the feed examples.
Added "cache" classes, to ease caching of html output for instance. (TODO: improve by providing a cache manager).

src/service/response/cms_response.e

@@ -423,6 +423,36 @@ feature -- Blocks initialization
 			Result := setup.text_item_or_default ("blocks." + a_block_id + ".region", a_default_region)
 		end
 
+	block_conditions (a_block_id: READABLE_STRING_8): detachable ARRAYED_LIST [CMS_BLOCK_EXPRESSION_CONDITION]
+				-- Condition associated with `a_block_id' in configuration, if any.
+		do
+			if attached setup.text_item ("blocks." + a_block_id + ".condition") as s then
+				create Result.make (1)
+				Result.force (create {CMS_BLOCK_EXPRESSION_CONDITION}.make (s))
+			end
+			if attached setup.text_list_item ("blocks." + a_block_id + ".conditions") as lst then
+				if Result = Void then
+					create Result.make (lst.count)
+					across
+						lst as ic
+					loop
+						Result.force (create {CMS_BLOCK_EXPRESSION_CONDITION}.make (ic.item))
+					end
+				end
+			end
+		end
+
+	is_block_included (a_block_id: READABLE_STRING_8; dft: BOOLEAN): BOOLEAN
+			-- Is block `a_block_id' included in current response?
+			-- If no preference, return `dft'.
+		do
+			if attached block_conditions (a_block_id) as l_conditions then
+				Result := across l_conditions as ic some ic.item.satisfied_for_response (Current) end
+			else
+				Result := dft
+			end
+		end
+
 feature -- Blocks regions
 
 	regions: STRING_TABLE [CMS_BLOCK_REGION]
@@ -457,10 +487,25 @@ feature -- Blocks regions
 			end
 		end
 
-feature -- Blocks 		
+feature -- Blocks
+
+	put_block (b: CMS_BLOCK; a_default_region: detachable READABLE_STRING_8; is_block_included_by_default: BOOLEAN)
+			-- Add block `b' to associated region or `a_default_region' if provided
+			-- and check optional associated condition.
+			-- If no condition then use `is_block_included_by_default' to
+			-- decide if block is included or not.
+		local
+			l_region: detachable like block_region
+		do
+			if is_block_included (b.name, is_block_included_by_default) then
+				l_region := block_region (b, a_default_region)
+				l_region.extend (b)
+			end
+		end
 
 	add_block (b: CMS_BLOCK; a_default_region: detachable READABLE_STRING_8)
 			-- Add block `b' to associated region or `a_default_region' if provided.
+			-- WARNING: ignore any block condition! USE WITH CARE!
 		local
 			l_region: detachable like block_region
 		do
@@ -473,29 +518,29 @@ feature -- Blocks
 			debug ("refactor_fixme")
 				fixme ("find a way to have this in configuration or database, and allow different order")
 			end
-			add_block (top_header_block, "top")
-			add_block (header_block, "header")
+			put_block (top_header_block, "top", True)
+			put_block (header_block, "header", True)
 			if attached message_block as m then
-				add_block (m, "content")
+				put_block (m, "content", True)
 			end
 			if attached primary_tabs_block as m then
-				add_block (m, "content")
+				put_block (m, "content", True)
 			end
-			add_block (content_block, "content")
+			add_block (content_block, "content") -- Can not be disabled!
 
 			if attached management_menu_block as l_block then
-				add_block (l_block, "sidebar_first")
+				put_block (l_block, "sidebar_first", True)
 			end
 			if attached navigation_menu_block as l_block then
-				add_block (l_block, "sidebar_first")
+				put_block (l_block, "sidebar_first", True)
 			end
 			if attached user_menu_block as l_block then
-				add_block (l_block, "sidebar_second")
+				put_block (l_block, "sidebar_second", True)
 			end
 
 			hooks.invoke_block (Current)
 			debug ("cms")
-				add_block (create {CMS_CONTENT_BLOCK}.make ("made_with", Void, "Made with <a href=%"http://www.eiffel.com/%">EWF</a>", Void), "footer")
+				put_block (create {CMS_CONTENT_BLOCK}.make ("made_with", Void, "Made with <a href=%"https://www.eiffel.org/%">EWF</a>", Void), "footer", True)
 			end
 		end