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If you read the dissertation, it turns out that variables are captured by value. But even if they are captured by reference - solutions are possible such as the
by nponeccop 15y ago
If you read the dissertation, it turns out that variables are captured by value. But even if they are captured by reference - solutions are possible such as the one in C++11. The decac doesn't provide more memory safety than C, so there are no problems :) Yet another solution is to inline all higher-order functions so no closures exist at runtime.
- eli_gottlieb 15y agoActually, this issue is what spurred a major evolution in the language. I hadn't had a real region or effect system before, and now I do. Why? I needed some way to register what pointers (regions) are getting captured by an existential package (aka: a lexical closure). Since regions are now registered as part of an existential package, the regions captured by a package can be constrained to suit the region of the stack up to which a package is being returned. In short, closures now remember what pointers they capture, and you won't be allowed to return a closure over a pointer further up the stack than safe. Other than that, closures capture by value, copying the captured variable into an environment structure.