assembler shenanigans. shiny ahh code.

assembler/src/lib.rs

@@ -1,5 +1,12 @@
+use core::fmt;
+
 use common::prelude::Instruction;
 
+use crate::{lexer::Token, parser::TokenType};
+
+pub mod lexer;
+pub mod parser;
+
 pub fn assemble(src: &str) -> Vec<Instruction> {
     todo!()
 }
@@ -12,3 +19,20 @@ pub fn disassemble(binary: Vec<Instruction>) -> String {
     //   sequences that are expansions of pseduo-instructions and reversing this to produce near enough the original source code.
     todo!()
 }
+
+#[derive(Debug)]
+pub enum AssembleError {
+    Generic,
+    UnexpectedToken(Token, TokenType),
+}
+
+impl fmt::Display for AssembleError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            AssembleError::Generic => write!(f, "Generic error"),
+            AssembleError::UnexpectedToken(tok, expected) => {
+                write!(f, "Unexpected token {:?}, expected {:?}", tok, expected)
+            }
+        }
+    }
+}