feat: functions with formal parameters

src/ty/internal/func.rs

@@ -1,8 +1,9 @@
 use ecow::EcoString;
+use itertools::Itertools;
 use rpds::HashTrieMap;
 
 use crate::bytecode::{OpCodes, ThunkIdx};
-use crate::ty::internal::Value;
+use crate::ty::internal::{Thunk, Value};
 
 use crate::vm::{LockedEnv, VM};
 
@@ -39,7 +40,38 @@ impl Func {
 
         match self.param.unwrap() {
             Ident(ident) => env.enter(HashTrieMap::new_sync().insert(ident.into(), arg)),
-            Formals { .. } => todo!()
+            Formals {
+                formals,
+                ellipsis,
+                alias,
+            } => {
+                let arg = arg.unwrap_attr_set();
+                let mut new = HashTrieMap::new_sync();
+                if !ellipsis
+                    && arg
+                        .as_inner()
+                        .iter()
+                        .map(|(k, _)| k.as_inner())
+                        .sorted()
+                        .ne(formals.iter().map(|(k, _)| k).sorted())
+                {
+                    todo!()
+                }
+                for (formal, default) in formals {
+                    // let arg = if let Some(default) = default {
+                    //     arg.select(format)
+                    // }
+                    let arg = arg
+                        .select(formal.clone().into())
+                        .or_else(|| default.map(|idx| Value::Thunk(Thunk(idx))))
+                        .unwrap();
+                    new.insert_mut(formal.into(), arg);
+                }
+                if let Some(alias) = alias {
+                    new.insert_mut(alias.into(), Value::AttrSet(arg));
+                }
+                env.enter(new);
+            }
         }
 
         vm.eval(self.opcodes, &mut env).unwrap()