[obsidian] vault backup: 2023-09-02 21:37:00[
This commit is contained in:
parent
f8ca2b6efd
commit
2f10426abf
@ -54,4 +54,44 @@ impl<'a, T: Clone> Drop for EnvironmentT<'a, T> {
|
||||
self.0.truncate(self.1);
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
なんかDropのタイミングがうまく制御できずコンパイルを通せない、、、
|
||||
し、綺麗ではあるけど言うほど記述量が減るわけではない
|
||||
|
||||
ので、evalを相互再帰するヘルパー関数とかでこういう感じにした方が楽かも
|
||||
|
||||
```rust
|
||||
fn eval_with_new_env<'a>(
|
||||
e_meta: Box<WithMeta<ast::Expr>>,
|
||||
env: &'a mut Vec<(String, Value)>,
|
||||
mut names: Vec<(String, Value)>,
|
||||
) -> Result<Value, Error> {
|
||||
let len_origin = env.len();
|
||||
env.append(&mut names);
|
||||
let res = eval_ast(e_meta, env);
|
||||
env.truncate(len_origin);
|
||||
res
|
||||
}
|
||||
fn eval_ast<'a>(
|
||||
e_meta: Box<WithMeta<ast::Expr>>,
|
||||
env: &'a mut Vec<(String, Value)>,
|
||||
) -> Result<Value, Error>{
|
||||
...
|
||||
match e {
|
||||
...
|
||||
ast::Expr::Let(TypedId { id, ty: _t }, e, then) => {
|
||||
let e_v = eval_ast(e, env)?;
|
||||
match then {
|
||||
Some(t) => eval_with_new_env(t, env, vec![(id, e_v)]),
|
||||
None => Ok(Value::Unit),
|
||||
}
|
||||
}
|
||||
...
|
||||
|
||||
}
|
||||
|
||||
}
|
||||
```
|
Loading…
Reference in New Issue
Block a user