feat: less clone, avoid evaluating not depended thunk

src/env.rs

@@ -6,10 +6,10 @@ use hashbrown::HashMap;
 
 use crate::error::{Error, Result};
 use crate::stack::Stack;
-use crate::ty::internal::{EnvRef, Value};
+use crate::ty::internal::Value;
 
 #[derive(Clone)]
-pub struct VmEnv {
+pub struct Env {
     cache: Vec<HashMap<usize, Value>>,
     with: Vec<Rc<HashMap<EcoString, Value>>>,
     args: Vec<Value>,
@@ -38,7 +38,7 @@ pub enum Type {
     With,
 }
 
-impl VmEnv {
+impl Env {
     pub fn new() -> Self {
         Self {
             cache: Vec::from([HashMap::new()]),
@@ -66,7 +66,7 @@ impl VmEnv {
     pub fn lookup_cache(
         &mut self,
         idx: usize,
-        f: impl FnOnce(&mut VmEnv) -> Result<Value>,
+        f: impl FnOnce(&mut Env) -> Result<Value>,
     ) -> Result<Value> {
         for level in self.cache.iter().rev() {
             if let Some(ret) = level.get(&idx) {
@@ -99,6 +99,10 @@ impl VmEnv {
         self.args.split_off(self.args.len() - len)
     }
 
+    pub fn reserve_args(&mut self, len: usize) {
+        self.args.reserve(len);
+    }
+
     pub fn enter_args(&mut self, args: Vec<Value>) {
         self.args.extend(args);
     }