On Sat, May 27, 2023 at 4:31 AM Alex Shinn <[email protected]> wrote:


> The expensive path is array-copy of an array-map or other generalized
> array.
>

True, but because array-map is lazy there is never any guarantee that
getting an element of an array constructed by array-map returns the same
value every time (e.g. it could return a random number), and so *actual*
safety, as opposed to formal call/cc-safety, is never guaranteed whether
you make an intermediate list or not.  A "sufficiently smart compiler"
could transform the idiom (array-copy (array-map ...)) to use array-copy!
instead.

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