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: options.rs
    path of file: ./repos/creusot/creusot/src
    
    the code of the file until where you have to start completion: use std::{
    collections::HashMap,
    path::{Path, PathBuf},
};

#[derive(Clone)]
pub enum SpanMode {
    Relative,
    Absolute,
    Off,
}

#[derive(Clone)]
pub enum Why3Sub {
    Prove,
    Ide,
    Replay,
}

#[derive(Clone)]
pub struct Why3Command {
    pub path: PathBuf,
    pub config_file: Option<PathBuf>,
    pub sub: Why3Sub,
    pub args: String,
}

#[derive(Clone)]
pub struct Options {
    pub extern_paths: HashMap<String, String>,
    pub metadata_pat
    
    pub fn relative_to_output(&self, p: &Path) -> PathBuf {
        let mut other = std::env::current_dir().unwrap();
        match &self.output_file {
            Some(OutputFile::File(s)) => {
                if Path::new(s).is_relative() {
                    other.push(s);
                }
            }
            _ => {
                other.push("dummy.mlcfg");
            }
        };

        let two = other.components();
        let one = p.components();

        let mut same = 0;
        one.zip(two).take_while(|(l, r)| l == r).for_each(|_| same += 1);
        let output_components = other.components().count();
        let mut buf = PathBuf::new();

        (0..(output_components - same)).for_each(|_| {
            // Why3 treats the spans as relative to the session, not the source file,
            // and the session is in a subdirectory next to the mlcfg file, so we need
            // to add ..
            buf.push("..");
            // then add the relative path of the root project with respect to the output
            // directory (typically some amount of ..)
            buf.extend(&self.root_path_relative_from_output)
        });
        buf.extend(p.components().skip(same));
        // the roundtrip through [components()] gives us some basic (syntactic)
        // normalization of the path (e.g. remove /./)
        buf.components().collect()
    }