scoped_stack

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.

Example

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);

  assert_eq!(stack.get(&"a"), Some(&1));
  assert_eq!(stack.get(&"b"), Some(&2));
  assert_eq!(stack.get(&"c"), Some(&3));

  stack.push_scope();

  stack.insert("a", 4);
  stack.insert("b", 5);

  assert_eq!(stack.get(&"a"), Some(&4));
  assert_eq!(stack.get(&"b"), Some(&5));
  assert_eq!(stack.get(&"c"), Some(&3));

  stack.pop_scope();

  assert_eq!(stack.get(&"a"), Some(&1));
  assert_eq!(stack.get(&"b"), Some(&2));
  assert_eq!(stack.get(&"c"), Some(&3));
}