assume utf-8

rust/src/compiler.rs

@@ -6,7 +6,7 @@ pub fn compile(source: &str) -> Result<()> {
 
     let mut line = None;
     loop {
-        let token = scanner.scan()?;
+        let token = scanner.scan();
         if Some(token.line) != line {
             print!("{:4} ", token.line);
             line = Some(token.line);

rust/src/scanner.rs

@@ -15,7 +15,7 @@ impl<'a> Scanner<'a> {
         }
     }
 
-    pub fn scan(&mut self) -> Result<Token> {
+    pub fn scan(&mut self) -> Token {
         self.skip_whitespace();
 
         if self.peek().is_none() {
@@ -69,20 +69,20 @@ impl<'a> Scanner<'a> {
         }
     }
 
-    fn make_token(&self, kind: TokenKind) -> Result<Token> {
+    fn make_token(&self, kind: TokenKind) -> Token {
-        Ok(Token {
+        Token {
             kind,
-            value: std::str::from_utf8(&self.source[..self.current])?,
+            value: std::str::from_utf8(&self.source[..self.current]).unwrap(),
             line: self.line,
-        })
+        }
     }
 
-    fn error_token(&self, message: &'static str) -> Result<Token> {
+    fn error_token(&self, message: &'static str) -> Token {
-        Ok(Token {
+        Token {
             kind: TokenKind::Error,
             value: message,
             line: self.line,
-        })
+        }
     }
 
     fn advance(&mut self) -> char {
@@ -135,7 +135,7 @@ impl<'a> Scanner<'a> {
         self.source.get(self.current + 1).map(|&x| x as char)
     }
 
-    fn string(&mut self) -> Result<Token> {
+    fn string(&mut self) -> Token {
         while matches!(self.peek(), Some(c) if c != '"') {
             if self.peek() == Some('\n') {
                 self.line += 1;
@@ -152,7 +152,7 @@ impl<'a> Scanner<'a> {
         self.make_token(TokenKind::String)
     }
 
-    fn number(&mut self) -> Result<Token> {
+    fn number(&mut self) -> Token {
         while matches!(self.peek(), Some(c) if c.is_ascii_digit()) {
             self.advance();
         }
@@ -168,7 +168,7 @@ impl<'a> Scanner<'a> {
         self.make_token(TokenKind::Number)
     }
 
-    fn identifier(&mut self) -> Result<Token> {
+    fn identifier(&mut self) -> Token {
         while matches!(self.peek(), Some(c) if is_alpha(c) || c.is_ascii_digit()) {
             self.advance();
         }
@@ -318,7 +318,7 @@ mod tests {
     }
 
     fn assert_scan(scanner: &mut Scanner, kind: TokenKind) {
-        let token = scanner.scan().unwrap();
+        let token = scanner.scan();
         assert_eq!(token.kind, kind);
     }
 }