pub fn parse_essence_file(

    path: &str,

    context: Arc<RwLock<Context<'static>>>,

) -> Result<Model, Box<ParseErrorCollection>> {

    let mut cmd = std::process::Command::new("conjure");

    let output = match cmd

        .arg("pretty")

        .arg("--output-format=astjson")

        .arg(path)

        .output()

        Ok(output) => output,

    if !output.status.success() {

        let stderr_string = String::from_utf8(output.stderr)

            .unwrap_or("stderr is not a valid UTF-8 string".to_string());

        return Err(Box::new(ParseErrorCollection::fatal(

            FatalParseError::ConjurePrettyError(stderr_string),

        )));

    }

    let astjson = match String::from_utf8(output.stdout) {

        Ok(astjson) => astjson,

    let parsed_model = model_from_json(&astjson, context)

        .map_err(|e| Box::new(ParseErrorCollection::fatal(e.into())))?;

    debug_assert_model_well_formed(&parsed_model, "via-conjure");

    Ok(parsed_model)

}