Check that teaser isn't too long before compiling

Rules

@@ -15,6 +15,8 @@ preprocess do
 
   articles.each {|item| item[:page_type] = 'single-post'}
   @items.each   {|item| item[:page_type] ||= 'static-page'}
+
+  validate_items
 end
 
 # Compilation ##################################################################

lib/validation.rb

@@ -0,0 +1,14 @@
+def validate_items
+  validate_teasers
+end
+
+def validate_teasers
+  @config[:validation] ||= {}
+  @config[:validation][:teaser_length] ||= 120
+  
+  @items.each do |i|
+    if i.key? :teaser and i[:teaser].length > @config[:validation][:teaser_length]
+      raise "Teaser too long for #{i.identifier}: #{i[:teaser].length} (should be #{@config[:validation][:teaser_length]})"
+    end
+  end
+end

nanoc.yaml

@@ -15,6 +15,9 @@ openid_id:      http://www.google.com/profiles/jez.cope
 
 page_size:      10
 
+validation:
+  teaser_length: 110
+
 # A list of file extensions that nanoc will consider to be textual rather than
 # binary. If an item with an extension not in this list is found,  the file
 # will be considered as binary.