You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: kcl_cursor.rs
    path of file: ./repos/kcl/kclvm/lexer/src
    
    the code of the file until where you have to start completion: //! KCL-specific cursor implementation,
//! including comment cursor, string cursor and identifier cursor.
//!
//! Todo: The implementation should be moved to [`parser::lexer`].
//! To do that, we should make IABCCursor as dynamic traits
//! and enable implemente Cursor structs in different crate.

use crate::cur
    
    fn eat_string(&mut self, c: char) -> TokenKind {
        match c {
            'r' | 'R' => match self.peek() {
                '\'' | '\"' => {
                    // R string
                    let quote = self.bump().unwrap_or(EOF_CHAR);
                    self.eat_quoted_string(quote)
                }
                _ => Unknown,
            },
            '\'' | '\"' => self.eat_quoted_string(c),
            _ => Unknown,
        }
    }