I don't recall where I first came across this word (it's been a while), but looking it up on the internet does show that there are a few different meanings for it.  The way I am describing it (hopefully clear) has closer ties with relational database; where the fields are addressable by name and by ordinals (in a data access layer).  <a href="http://en.wikipedia.org/wiki/Tuple#Usage_in_computer_science">http://en.wikipedia.org/wiki/Tuple#Usage_in_computer_science</a> - describes a few different tuple uses. Perhaps you are thinking of the ordinal-only tuple, which is quite similar to a vector? <div>On 6/1/07, Robby Findler <<a href="mailto:robby@cs.uchicago.edu">robby@cs.uchicago.edu</a>> wrote:<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> Where did you get the word "tuple" from? It doesn't seem to be ML-style tuples (which is where I am used to word from). Robby On 6/1/07, YC <<a href="mailto:yinso.chen@gmail.com">yinso.chen@gmail.com </a>> wrote: > IMO, Tuple is dissimilar from hash in that the fields are both named and > ordered (like a struct - that's why I call it an anonymous struct), where as > hashes have no guarantee on the order of the fields...  in a way tuple is > similar to alist. > > CTOR and dtor are needed for properly acquire and release external resources > - but this might not be the scheme way... I don't know for sure yet. > > yinso > > On 5/31/07, Carl Eastlund <<a href="mailto:cce@ccs.neu.edu">cce@ccs.neu.edu</a>> wrote: > > On 6/1/07, YC <<a href="mailto:yinso.chen@gmail.com">yinso.chen@gmail.com</a>> wrote: > > > Tuples differ from vectors that they are indexed both by name & numbers, > but > > > if struct is a named vector, in that sense it won't really be different, > > > except struct is opaque and hence better for building AST than vector > IMHO. > > > > Ok, you want tuples with labelled fields.  Now they sound more like > > hash tables on symbols or strings.  Are they anything beyond that? > > > > -- > > Carl Eastlund > > > > > _________________________________________________ >   For list-related administrative tasks: >   <a href="http://list.cs.brown.edu/mailman/listinfo/plt-scheme">http://list.cs.brown.edu/mailman/listinfo/plt-scheme </a> > > </blockquote></div>