Giulio Agostini
827349cbad
The commit rewrites the environment to use a stack of hash maps for managing variable scopes. This replaces the old parent-reference approach with a simpler and more efficient stack-based model. Key changes: - Rename Environment to EnvironmentStack - Store scopes in a Vec of HashMaps - Add push/pop scope operations for block handling - Update interpreter to properly manage scope lifetimes - Clean up error handling with helper functions
46 lines
1.1 KiB
Rust
46 lines
1.1 KiB
Rust
use std::collections::HashMap;
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use crate::{
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frontend::{source_registry::SourceSlice, tokens::LiteralValue},
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result::{runtime_error, LoxResult},
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};
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#[derive(Debug, Clone)]
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pub struct EnvironmentStack {
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stack: Vec<HashMap<String, LiteralValue>>,
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}
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impl EnvironmentStack {
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pub fn new() -> Self {
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EnvironmentStack {
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stack: vec![HashMap::new()],
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}
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}
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pub fn push_new_scope(&mut self) {
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self.stack.push(HashMap::new());
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}
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pub fn pop_scope(&mut self) {
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self.stack.pop();
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}
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pub fn get(&self, name: &str) -> LoxResult<LiteralValue> {
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let size = self.stack.len();
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for i in (0..size).rev() {
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if let Some(value) = self.stack[i].get(name) {
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return Ok(value.clone());
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}
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}
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runtime_error(
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SourceSlice::default(), // todo change this to the actual source slice
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format!("Undefined variable '{}'", name),
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)
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}
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pub fn set(&mut self, name: String, value: LiteralValue) {
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self.stack.last_mut().unwrap().insert(name, value);
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}
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}
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