feat: error handling (WIP)

src/ty/internal/primop.rs

@@ -1,6 +1,7 @@
 use derive_more::Constructor;
 
 use crate::vm::VM;
+use crate::error::Result;
 
 use super::Value;
 
@@ -8,7 +9,7 @@ use super::Value;
 pub struct PrimOp<'vm> {
     pub name: &'static str,
     arity: u8,
-    func: fn(&'vm VM<'_>, Vec<Value<'vm>>) -> Value<'vm>,
+    func: fn(&'vm VM<'_>, Vec<Value<'vm>>) -> Result<Value<'vm>>,
 }
 
 impl PartialEq for PrimOp<'_> {
@@ -18,14 +19,14 @@ impl PartialEq for PrimOp<'_> {
 }
 
 impl<'vm> PrimOp<'vm> {
-    pub fn call(self, vm: &'vm VM<'_>, args: Vec<Value<'vm>>) -> Value<'vm> {
+    pub fn call(self, vm: &'vm VM<'_>, args: Vec<Value<'vm>>) -> Result<Value<'vm>> {
         if (args.len() as u8) < self.arity {
             Value::PartialPrimOp(PartialPrimOp {
                 name: self.name,
                 arity: self.arity - args.len() as u8,
                 args,
                 func: self.func,
-            })
+            }).ok()
         } else if args.len() as u8 == self.arity {
             (self.func)(vm, args)
         } else {
@@ -39,7 +40,7 @@ pub struct PartialPrimOp<'vm> {
     pub name: &'static str,
     arity: u8,
     args: Vec<Value<'vm>>,
-    func: fn(&'vm VM<'_>, Vec<Value<'vm>>) -> Value<'vm>,
+    func: fn(&'vm VM<'_>, Vec<Value<'vm>>) -> Result<Value<'vm>>,
 }
 
 impl PartialEq for PartialPrimOp<'_> {
@@ -49,7 +50,7 @@ impl PartialEq for PartialPrimOp<'_> {
 }
 
 impl<'vm> PartialPrimOp<'vm> {
-    pub fn call(mut self, vm: &'vm VM<'_>, args: Vec<Value<'vm>>) -> Value<'vm> {
+    pub fn call(mut self, vm: &'vm VM<'_>, args: Vec<Value<'vm>>) -> Result<Value<'vm>> {
         let len = args.len() as u8;
         self.args.extend(args);
         if len < self.arity {
@@ -58,7 +59,7 @@ impl<'vm> PartialPrimOp<'vm> {
                 arity: self.arity - len,
                 args: self.args,
                 func: self.func,
-            })
+            }).ok()
         } else if len == self.arity {
             (self.func)(vm, self.args)
         } else {