From 5fc4d355a8aab8d6ad1adbef667ae8f84e402784 Mon Sep 17 00:00:00 2001
From: YannAhlgrim <yann@ahlgrim.net>
Date: Tue, 12 May 2026 16:43:24 +0200
Subject: [PATCH] fix u8 error

---
 src/lexer/mod.rs | 20 +++++++++++++-------
 src/main.rs      |  2 +-
 src/token/mod.rs |  4 ++--
 3 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/src/lexer/mod.rs b/src/lexer/mod.rs
index 347966a..8d321e0 100644
--- a/src/lexer/mod.rs
+++ b/src/lexer/mod.rs
@@ -3,12 +3,9 @@ use crate::token::lookup_ident;
 use super::token::ASSIGN;
 use super::token::COMMA;
 use super::token::EOF;
-use super::token::FUNCTION;
-use super::token::IDENT;
 use super::token::ILLEGAL;
 use super::token::INT;
 use super::token::LBRACE;
-use super::token::LET;
 use super::token::LPAREN;
 use super::token::PLUS;
 use super::token::RBRACE;
@@ -34,8 +31,8 @@ pub trait LexerTraits {
 pub fn new(input_str: String) -> Lexer {
     let mut l: Lexer = Lexer {
         input: input_str,
-        position: Some(0),
-        read_pos: Some(1),
+        position: Some(-1),
+        read_pos: Some(0),
         ch: Some(0),
     };
     l.read_char();
@@ -68,6 +65,7 @@ impl LexerTraits for Lexer {
         let c = char::from(lit);
 
         match c {
+            '\0' => tok = new_token(EOF, lit),
             '=' => tok = new_token(ASSIGN, lit),
             ';' => tok = new_token(SEMICOLON, lit),
             '(' => tok = new_token(LPAREN, lit),
@@ -80,10 +78,10 @@ impl LexerTraits for Lexer {
                 if c.is_alphabetic() {
                     let lit = self.read_identifier();
                     let tok_type = lookup_ident(&lit);
-                    return new_token(tok_type, lit.as_bytes()[0]);
+                    return new_token_from_str(tok_type, lit);
                 } else if c.is_ascii_digit() {
                     let lit = self.read_number();
-                    return new_token(INT, lit.as_bytes()[0]);
+                    return new_token_from_str(INT, lit);
                 } else {
                     tok = new_token(ILLEGAL, lit);
                 }
@@ -135,3 +133,11 @@ fn new_token(token_type: &str, ch: u8) -> Token {
         literal: lit,
     }
 }
+
+fn new_token_from_str(token_type: &str, lit: String) -> Token {
+    let token_type = String::from(token_type);
+    Token {
+        type_: token_type,
+        literal: lit,
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index c3714cd..28d45ec 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -14,7 +14,7 @@ fn main() {
 
     let mut l = new(input.to_string());
 
-    for (i, tok) in (0..36).map(|_| l.next_token()).enumerate() {
+    for (_i, tok) in (0..37).map(|_| l.next_token()).enumerate() {
         println!("{}: {:?}", tok.type_, tok.literal);
     }
 }
diff --git a/src/token/mod.rs b/src/token/mod.rs
index c4555d5..eae46e4 100644
--- a/src/token/mod.rs
+++ b/src/token/mod.rs
@@ -21,10 +21,10 @@ pub const RBRACE: &str = "}";
 pub const FUNCTION: &str = "FUNCTION";
 pub const LET: &str = "LET";
 
-pub fn lookup_ident(ident: &str) -> &str {
+pub fn lookup_ident(ident: &str) -> &'static str {
     match ident {
         "fn" => FUNCTION,
         "let" => LET,
-        _ => ILLEGAL,
+        _ => IDENT,
     }
 }