Implement getUnknownMessage in UnknownOption

This allows to retrive the unknown option in
question when catching the error.
This can be useful to, for example, taylor a
spesific output for common errors amongst users.

3 files changed, 18 insertions, 2 deletions

diff --git a/lib/slop/error.rb b/lib/slop/error.rb
index 55e0fe0..776b939 100644
--- a/lib/slop/error.rb
+++ b/lib/slop/error.rb
@@ -16,5 +16,14 @@ module Slop
 
   # Raised when an unknown option is parsed. Suppress
   # with the `suppress_errors` config option.
-  class UnknownOption   < Error; end
+  class UnknownOption   < Error;
+    def initialize(msg, unknownOption)
+      super(msg);
+      @unknownOption = unknownOption;
+    end
+
+    def getUnknowOption()
+      return @unknownOption;
+    end
+  end
 end
diff --git a/lib/slop/parser.rb b/lib/slop/parser.rb
index 246da9f..8474e5d 100644
--- a/lib/slop/parser.rb
+++ b/lib/slop/parser.rb
@@ -102,7 +102,7 @@ module Slop
         try_process(last, arg) # send the argument to the last flag
       else
         if flag.start_with?("-") && !suppress_errors?
-          raise UnknownOption, "unknown option `#{flag}'"
+          raise UnknownOption.new "unknown option `#{flag}'", "#{flag}"
         end
       end
     end
diff --git a/test/error_test.rb b/test/error_test.rb
index 6a33c04..7ea30fc 100644
--- a/test/error_test.rb
+++ b/test/error_test.rb
@@ -21,6 +21,13 @@ describe Slop::UnknownOption do
     opts = Slop::Options.new
     opts.string "-n", "--name"
     assert_raises(Slop::UnknownOption) { opts.parse %w(--foo) }
+
+    #Assert returns the unknown option in quetion
+    begin
+      opts.parse %w(--foo)
+    rescue Slop::UnknownOption => e
+      assert_equal(e.getUnknowOption(), "--foo");
+    end
   end
 
   it "does not raise when errors are suppressed" do