pub fn peek_token(&mut self) -> Result<Token, Error> {
      let location = self.location;
      let token = self.next_token()?;
      self.location = location;
      Ok(token)
   }
/// Peeks at what the next token's going to be without advancing the lexer's position.
Peeks at what the next token's going to be without advancing the lexer's position.
Peeks at what the next token ' s going to be without advancing the lexer ' s position .
pub fn peek_token(&mut self) -> Result<Token, Error> {
      let location = self.location;
      let token = self.next_token()?;
      self.location = location;
      Ok(token)
   }
pub fn peek_token ( & mut self ) -> Result < Token , Error > { let location = self . location ; let token = self . next_token ( ) ? ; self . location = location ; Ok ( token ) }
Peeks at what the next token's going to be without advancing the lexer's position.
Peeks at what the next token ' s going to be without advancing the lexer ' s position .
&mut self