44 lines
1.1 KiB
Rust
44 lines
1.1 KiB
Rust
use std::collections::HashMap;
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use std::hash::Hash;
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use std::cmp::Eq;
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#[derive(Default, Debug)]
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pub struct ScopeStack<'a, T: 'a, V: 'a> where T: Hash + Eq {
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parent: Option<&'a ScopeStack<'a, T, V>>,
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values: HashMap<T, V>,
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scope_name: Option<String>
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}
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impl<'a, T, V> ScopeStack<'a, T, V> where T: Hash + Eq {
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pub fn new(name: Option<String>) -> ScopeStack<'a, T, V> where T: Hash + Eq {
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ScopeStack {
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parent: None,
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values: HashMap::new(),
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scope_name: name
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}
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}
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pub fn insert(&mut self, key: T, value: V) where T: Hash + Eq {
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self.values.insert(key, value);
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}
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pub fn lookup(&self, key: &T) -> Option<&V> where T: Hash + Eq {
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match (self.values.get(key), self.parent) {
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(None, None) => None,
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(None, Some(parent)) => parent.lookup(key),
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(Some(value), _) => Some(value),
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}
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}
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pub fn new_scope(&'a self, name: Option<String>) -> ScopeStack<'a, T, V> where T: Hash + Eq {
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ScopeStack {
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parent: Some(self),
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values: HashMap::default(),
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scope_name: name,
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}
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}
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#[allow(dead_code)]
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pub fn get_name(&self) -> Option<&String> {
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self.scope_name.as_ref()
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}
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}
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