On Thu, Aug 18, 2011 at 9:09 AM, Harry Spier <harrysp...@hotmail.com> wrote: > Dear list members, > > Firstly thank you, for clarifying uninterned symbols. > > I've tried running the examples for reading graph structure in the reference > manual 12.6.16 in DrRacket. > > When I put (#1=100 #1# #1#) in either the definitions or interactions > window I get > > . read: #..= expressions not allowed in read-syntax mode > > I've tried '(#1=100 #1# #1#) and it gives me the same error.
Try this: > (read (open-input-string "(#1=100 #1# #1#)")) Cyclic data is not allowed in *programs*, which is what you type in at the REPL. > Also I'm not clear how #0=(1 . #0#) converts to > (let ([v (cons 1 #f)]) > (set-cdr! v v) v) It doesn't convert to that -- the cyclic data is directly constructed by the reader. Note also that pairs constructed by `cons' are immutable, and thus your code won't work (that's why the reader is necessary here). See also `shared': http://docs.racket-lang.org/reference/shared.html?q=shared#%28form._%28%28lib._racket/shared..rkt%29._shared%29%29 -- sam th sa...@ccs.neu.edu _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
