0264408
45 lines
1.1 KiB
Rust
45 lines
1.1 KiB
Rust
use super::Value;
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use std::collections::HashMap;
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use std::rc::Rc;
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use std::cell::RefCell;
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#[derive(Debug)]
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pub struct Env {
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pub values: HashMap<String, Value>,
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pub parent: Option<Rc<RefCell<Env>>>,
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}
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impl Env {
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pub fn new(parent: Option<Rc<RefCell<Env>>>) -> Self {
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Self {
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values: HashMap::new(),
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parent,
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}
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}
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pub fn define(&mut self, name: String, val: Value) {
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self.values.insert(name, val);
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}
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pub fn assign(&mut self, name: &str, val: Value) -> bool {
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if self.values.contains_key(name) {
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self.values.insert(name.to_string(), val);
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true
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} else if let Some(parent) = &self.parent {
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parent.borrow_mut().assign(name, val)
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} else {
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false
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}
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}
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pub fn get(&self, name: &str) -> Option<Value> {
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if let Some(val) = self.values.get(name) {
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Some(val.clone())
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} else if let Some(parent) = &self.parent {
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parent.borrow().get(name)
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} else {
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None
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}
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}
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}
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