scoped_stack is a Rust library that provides a stack that can be scoped. Each ScopedStack has a HashMap of values and a child ScopedStack. When a scope is pushed, a new ScopedStack is created with the uppermost ScopedStack as its parent. When a scope is popped, the uppermost ScopedStack is removed. When a value is pushed, it is added to the uppermost ScopedStack. When a value is popped, it is removed from the uppermost ScopedStack with that key. When a value is looked up, the value from the uppermost ScopedStack with that key is returned.
```rust use scoped_stack::ScopedStack;
fn main() { let mut stack = ScopedStack::<&str, i32>::new();
stack.insert("a", 1); stack.insert("b", 2); stack.insert("c", 3);
asserteq!(stack.get(&"a"), Some(&1)); asserteq!(stack.get(&"b"), Some(&2)); assert_eq!(stack.get(&"c"), Some(&3));
stack.push_scope();
stack.insert("a", 4); stack.insert("b", 5);
asserteq!(stack.get(&"a"), Some(&4)); asserteq!(stack.get(&"b"), Some(&5)); assert_eq!(stack.get(&"c"), Some(&3));
stack.pop_scope();
asserteq!(stack.get(&"a"), Some(&1)); asserteq!(stack.get(&"b"), Some(&2)); assert_eq!(stack.get(&"c"), Some(&3)); } ```