Ignore some instance variables

lib/better_errors.rb

@@ -32,8 +32,13 @@ class << self
 
     # @private
     alias_method :binding_of_caller_available?, :binding_of_caller_available
+
+    # The ignored instance variables.
+    # @return [Array]
+    attr_accessor :ignored_instance_variables
   end
-
+  @ignored_instance_variables = []
+
   # Returns a proc, which when called with a filename and line number argument,
   # returns a URL to open the filename and line in the selected editor.
   # 

lib/better_errors/stack_frame.rb

@@ -95,11 +95,15 @@ def local_variables
 
     def instance_variables
       return {} unless frame_binding
-      Hash[frame_binding.eval("instance_variables").map { |x|
+      Hash[visible_instance_variables.map { |x|
         [x, frame_binding.eval(x.to_s)]
       }]
     end
-
+
+    def visible_instance_variables
+      frame_binding.eval("instance_variables") - BetterErrors.ignored_instance_variables
+    end
+
     def to_s
       "#{pretty_path}:#{line}:in `#{name}'"
     end

spec/better_errors/error_page_spec.rb

@@ -48,6 +48,15 @@ module BetterErrors
         html.should include("inst_d")
         html.should include(":value_for_inst_d")
       end
+
+      it "should show filter instance variables" do
+        BetterErrors.stub(:ignored_instance_variables).and_return([ :@inst_d ])
+        html = error_page.do_variables("index" => 0)[:html]
+        html.should include("inst_c")
+        html.should include(":value_for_inst_c")
+        html.should_not include('<td class="name">@inst_d</td>')
+        html.should_not include("<pre>:value_for_inst_d</pre>")
+      end
     end
 
     it "should not die if the source file is not a real filename" do