On 18 Sep 2024, at 17:25, Marc Nieper-Wißkirchen <marc.nie...@gmail.com> wrote:
> And the text reflects this by saying that the keys should have locations. > This means that you won't see a catastrophic failure, but you have to know > what you do (and your implementation of SRFI 254). > >> I think it is probably a bad idea, because what has location and what >> does not is implementation-dependent – beyond matters which, in R6 and > > It is partially implementation-dependent, which is an important distinction. > The RnRS define a lot of value types that have locations. In order words, it is implementation-dependent. Writing portable code that uses SRFI 254 will be a nightmare if it is not possible to pass any given object into an ephemeron or guardian. I would maybe accept a restriction on passing some very minimal set of types as keys to an ephemeron: #t, #f, '(). Anything else might have location in a given implementation. (We mustn’t forget that R7-small implementations with no fixnums, i.e. where all numbers are boxed like in CPython, may also want to support SRFI 254.) Daphne
