At Sat, 21 Apr 2012 15:32:15 -0400, Chad Albers wrote: > Otherwise, I > just don't understand what the use-case is for adding the port property to > the struct. Might as well just assign one of the struct's fields to be a > port, rather than the ceremony of setting a property on the struct.
Occasionally, you have to provide a port to some library or callback, and when you eventually get a port back, you want to recognize the port as one that you created. For example, `open-output-string' produces an output port, but `get-output-string' needs to recognize exactly those ports that are produced by `open-output-string' so that it can extract an accumulated string. That use case is not common, however, and as you have sorted out, `prop:input-port' and `prop:output-port' are not substitutes for `make-input-port' and `make-output-port'. ____________________ Racket Users list: http://lists.racket-lang.org/users
