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It is my recollection that the official Arc uses incompatible features. I can't remember where I read this, so it's entirely possible I am incorrect.
by bmitc 3y ago
It is my recollection that the official Arc uses incompatible features. I can't remember where I read this, so it's entirely possible I am incorrect.
- gus_massa 3y agoArc mutates inmutable pairs (cons), it worked initially because at the C level mutable and immutable pairs were the same struct. Now there is a primitive unsafe-set-immutable-car! [1] for cases like this. It's a weird primitive and should be used with a lot of care as explained in the docs. [1] https://docs.racket-lang.org/reference/unsafe.html#%28def._%28%28lib._racket%2Funsafe%2Fops..rkt%29._unsafe-set-immutable-car%21%29%29 https://docs.racket-lang.org/reference/unsafe.html#%28def._%...