[obsidian] vault backup: 2023-09-01 18:50:32[

This commit is contained in:
Tomoya Matsuura(MacBookPro) 2023-09-01 18:50:32 +09:00
parent 1f02303cb4
commit 56b35ed5ee

View File

@ -20,14 +20,28 @@ fn eval<'a>(expr:Expr,env:&'a mut Vec<(String,Val)>)->Result<Val,Error>{
Environmentは評価全体で見ればLetやLambdaごとに分岐していく構造だけれど、局所的には1列のベクタで表現できる
こんな感じすかねえ
```rust
struct<'a,T> Environment(&'a mut Vec<T>)
impl<'a,T> Environment{
pub fn new()->Self{
Self(&mut Vec::new())
}
struct EnvironmentT<'a, T>(&'a mut Vec<(String, T)>, usize);
impl<'a, T> EnvironmentT<'a, T> {
pub fn new(vec: &'a mut Vec<(String, T)>, mut names: Vec<(String, T)>) -> Self {
let len = vec.len();
vec.append(&mut names);
Self(vec, len)
}
pub fn drop(&mut self) {
self.0.truncate(self.1);
}
pub fn lookup(&self, name: &String) -> Option<&'a T> {
let res = self
.0
.iter()
.rev()
.filter(|(n, _v)| name == n)
.collect::<Vec<_>>();
res.get(0).map(|(_, v)| v)
}
}
```