From 0065b1fb9d4fc7a2b801aac34d7c9c3139b4c9ca Mon Sep 17 00:00:00 2001
From: Patric Bucher <patricbucher@gmail.com>
Date: Thu, 2 Nov 2023 22:21:45 +0100
Subject: [PATCH] Making use of enum_primitive_derive

This simplifies converting back from a u8 to the OpCodes enum
---
 Cargo.toml      |  2 ++
 src/vm/block.rs | 27 +++++++++------------------
 2 files changed, 11 insertions(+), 18 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 8453b46..22c2f67 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,6 +7,8 @@ edition = "2021"
 
 [dependencies]
 colored = "2.0.4"
+enum-primitive-derive = "0.2.2"
+num-traits = "0.2.17"
 
 [features]
 disassemble = []
\ No newline at end of file
diff --git a/src/vm/block.rs b/src/vm/block.rs
index 51a5ca8..5d9f9a7 100644
--- a/src/vm/block.rs
+++ b/src/vm/block.rs
@@ -1,22 +1,13 @@
 use crate::vm::constants::Constants;
-use std::convert::TryFrom;
 
-#[derive(Debug)]
-pub enum OpCode {
-    Constant,
-    Return,
-}
-
-impl TryFrom<u8> for OpCode {
-    type Error = ();
+use enum_primitive_derive::Primitive;
+use num_traits::FromPrimitive;
 
-    fn try_from(value: u8) -> Result<Self, Self::Error> {
-        match value {
-            0 => Ok(OpCode::Constant),
-            1 => Ok(OpCode::Return),
-            _ => Err(()),
-        }
-    }
+#[repr(u8)]
+#[derive(Debug, Primitive)]
+pub enum OpCode {
+    Constant = 0x00,
+    Return = 0x01,
 }
 
 #[allow(dead_code)]
@@ -64,7 +55,7 @@ impl BlockDbg for Block {
 
         let mut offset: usize = 0;
         while offset < self.instructions.len() {
-            offset += self.disassemble_instruction(offset);
+            offset = self.disassemble_instruction(offset);
         }
 
         println!("=== </{}> ===", self.name);
@@ -73,7 +64,7 @@ impl BlockDbg for Block {
     fn disassemble_instruction(&self, offset: usize) -> usize {
         print!("{:04x} ", offset);
 
-        let instruction = OpCode::try_from(self.instructions[offset]).unwrap();
+        let instruction = OpCode::from_u8(self.instructions[offset]).unwrap();
         return match instruction {
             OpCode::Constant => self.constant_instruction(OpCode::Constant, offset),
             OpCode::Return => self.simple_instruction(OpCode::Return, offset),