How to create a simple, reusable local lambda

[alice]

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"Closure" closing on mutable outer value?

Hi Friends! While working through "the book" on closures that change environment I become curious whether we have a way to capture mutable outer variable which is going to change between lambda invocations. E.g. fn main() { let mut a = 5; let mut f = | x | { x + a }; println!("{}", f(7)); a *= a; println!("{}", f(7)); } this won't compile due to a being borrowed on lambda definition if I get it right. Is there a way to fix it (so that first invocation prints 12 and next 3…