From ffe5d2ad6122ccfdd75c5b8a38ea5d771c10bddf Mon Sep 17 00:00:00 2001
From: Scott Richmond <kredati@users.noreply.github.com>
Date: Wed, 18 Jun 2025 16:47:53 -0400
Subject: [PATCH] panic on wrong number of args to functions

---
 src/value.rs | 15 ++++++++++++++-
 src/vm.rs    |  6 ++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/src/value.rs b/src/value.rs
index 190f343..b260fa7 100644
--- a/src/value.rs
+++ b/src/value.rs
@@ -45,6 +45,13 @@ impl LFn {
         }
     }
 
+    pub fn accepts(&self, arity: u8) -> bool {
+        match self {
+            LFn::Defined { chunks, .. } => chunks.iter().any(|(a, _)| *a == arity),
+            LFn::Declared { .. } => unreachable!(),
+        }
+    }
+
     pub fn name(&self) -> &'static str {
         match self {
             LFn::Declared { name } | LFn::Defined { name, .. } => name,
@@ -52,7 +59,6 @@ impl LFn {
     }
 
     pub fn chunk(&self, arity: u8) -> &Chunk {
-        // println!("Getting chunk of {arity} from {:?}", self);
         match self {
             LFn::Declared { .. } => unreachable!(),
             LFn::Defined { chunks, .. } => &chunks.iter().find(|(a, _)| *a == arity).unwrap().1,
@@ -268,4 +274,11 @@ impl Value {
             Partial(..) => "fn",
         }
     }
+
+    pub fn as_fn(&self) -> &LFn {
+        match self {
+            Value::Fn(inner) => inner.as_ref(),
+            _ => unreachable!(),
+        }
+    }
 }
diff --git a/src/vm.rs b/src/vm.rs
index 8555a78..503e63b 100644
--- a/src/vm.rs
+++ b/src/vm.rs
@@ -790,6 +790,12 @@ impl Vm {
 
                     match val {
                         Value::Fn(_) => {
+                            if !val.as_fn().accepts(arity) {
+                                return self.panic_with(format!(
+                                    "wrong number of arguments to {} passing {arity} args",
+                                    val.show()
+                                ));
+                            }
                             let mut frame = CallFrame {
                                 function: val,
                                 arity,