Dan Doel wrote: ... > Which version of ruby are you using? > > I copied, pasted and got no errors with the mswin32 1.8.0 build. > > - Dan Weird, I did the same (with yesterdays cvs mswin32 build) and got the error. IMO it is erroneous Ruby code anyway - maybe the following snippet is somewhat illuminating. ---- def sum result = 0 self.each { |*elt| p elt; result += yield(*elt) } result end public :sum un_mod = [[1,2],[3,4]] mod = un_mod.clone def mod.each super {|e| yield *e } end mod.sum { |a,b| b } # runs fine p "###" un_mod.sum { |a,b| b } # gives an error. --- this results in --- [1, 2] [3, 4] "###" [[1, 2]] D:/rb75.tmp:3:in `+': nil can't be coerced into Fixnum (TypeError) from D:/rb75.tmp:3:in `sum' ... ------------ /Christoph Please send off list mail to 'my_mail / gmy.net'.gsub(/y/,'x')