Am I inferring correctly that you are saying closure consumes a constant factor of memory over struct, but otherwise doesn't necessarily hold onto unnecessarily references from the stack? Any other way besides closure & struct to create opaque compound value objects? Thanks, yinso <div>On 5/31/07, 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;"> The size of a closure is proportional to the number of free variables in the function. A struct with an equivalent number of slots uses less memory, however. Robby On 5/31/07, YC <<a href="mailto:yinso.chen@gmail.com"> yinso.chen@gmail.com</a>> wrote: > > On 5/31/07, Carl Eastlund <<a href="mailto:cce@ccs.neu.edu">cce@ccs.neu.edu</a>> wrote: > > > In principle, a closure is essentially a struct.  All that needs to be > > > stored is a code pointer and references to any free variables.  How > > > efficient this is in practice depends a lot on the particular > > > implementation.  Are you asking in general, or about PLT Scheme > > > specifically? > > I am specifically interested in PLT Scheme (general info is also of interest > but secondary). > >  Does closure hold references to the stack?  I've heard that Scheme doesn't > keep variables on the stack, but want to verify. > >  If closure is as efficient as a struct that's great - I am finding myself > leaning toward closure because it can be created anonymously and ad hoc, but > doing so with struct is a lot harder. > >  Thanks, >  yinso > > > _________________________________________________ >   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>