>>>>> "T" == Tobias Reif <tobiasreif / pinkjuice.com> writes:

T> One time, a Foo is returned, the other time, a String is returned.

 What is your version of ruby ?

pigeon% irb
irb(main):001:0> class Foo < String
irb(main):002:1> end
nil
irb(main):003:0> f = Foo.new 'foo'
"foo"
irb(main):004:0> f.upcase.type
Foo
irb(main):005:0> f.reverse.type
Foo
irb(main):006:0> 
pigeon% 


Guy Decoux