firstly had issue finding #:: method of stream. got resolved this . now looking below method in stream def iterate[a](start: a, len: int)(f: => a): stream[a] the stream api has no mention of it. secondly in scala doc, why can't have inner classes defined in same respective parent class itself. why user has go , click @ c character on left panel search stream.conswrapper when directly read inside documentation stream itself? am missing something? scala newbie (3 months), if new user can't used it, of not able to. iterate not method of stream class, method of stream object. described here . from scaladoc page stream class linked, can go directly scaladoc page stream object clicking on "c" (for "class") icon @ top, , clicking on "o" icon. as finding operators, can click on "#" @ top of left search panel, brings this page lists operators of standard library. there can find mention of #:: operator , c...