refactor: reduce coupling

evaluator/nixjit_eval/src/value/primop.rs

@@ -0,0 +1,75 @@
+use std::rc::Rc;
+
+use derive_more::Constructor;
+
+use nixjit_error::Result;
+
+use super::Value;
+use crate::EvalContext;
+
+#[derive(Debug, Clone, Constructor)]
+pub struct PrimOp<Ctx: EvalContext> {
+    pub name: &'static str,
+    arity: usize,
+    func: fn(Vec<Value<Ctx>>, &Ctx) -> Result<Value<Ctx>>,
+}
+
+impl<Ctx: EvalContext> PrimOp<Ctx> {
+    pub fn call(&self, args: Vec<Value<Ctx>>, ctx: &Ctx) -> Result<Value<Ctx>> {
+        if args.len() > self.arity {
+            todo!()
+        }
+        if self.arity > args.len() {
+            Value::PrimOpApp(Rc::new(PrimOpApp {
+                name: self.name,
+                arity: self.arity - args.len(),
+                args,
+                func: self.func,
+            }))
+            .ok()
+        } else {
+            (self.func)(args, ctx)
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct PrimOpApp<Ctx: EvalContext> {
+    pub name: &'static str,
+    arity: usize,
+    args: Vec<Value<Ctx>>,
+    func: fn(Vec<Value<Ctx>>, &Ctx) -> Result<Value<Ctx>>,
+}
+
+impl<Ctx: EvalContext> Clone for PrimOpApp<Ctx> {
+    fn clone(&self) -> Self {
+        Self {
+            name: self.name,
+            arity: self.arity,
+            args: self.args.clone(),
+            func: self.func,
+        }
+    }
+}
+
+impl<Ctx: EvalContext> PrimOpApp<Ctx> {
+    pub fn call(self: &mut Rc<Self>, args: Vec<Value<Ctx>>, ctx: &Ctx) -> Result<Value<Ctx>> {
+        if self.arity < args.len() {
+            todo!()
+        }
+        let func = self.func;
+        let Some(ret) = ({
+            let self_mut = Rc::make_mut(self);
+            self_mut.arity -= args.len();
+            self_mut.args.extend(args);
+            if self_mut.arity == 0 {
+                Some(func(std::mem::take(&mut self_mut.args), ctx))
+            } else {
+                None
+            }
+        }) else {
+            return Value::PrimOpApp(self.clone()).ok();
+        };
+        ret
+    }
+}