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    use std::error::Error;
    use std::fmt;
    use std::mem;

    use yaml_rust as yaml;

    use crate::map::Map;
    use crate::value::{Value, ValueKind};

    pub fn parse(
        uri: Option<&String>,
        text: &str,
    ) -> Result<Map<String, Value>, Box<dyn Error + Send + Sync>> {
        // Parse a YAML object from file
        let mut docs = yaml::YamlLoader::load_from_str(text)?;
        let root = match docs.len() {
            0 => yaml::Yaml::Hash(yaml::yaml::Hash::new()),
            1 => mem::replace(&mut docs[0], yaml::Yaml::Null),
            n => {
                return Err(Box::new(MultipleDocumentsError(n)));
            }
        };

        // TODO: Have a proper error fire if the root of a file is ever not a Table
        let value = from_yaml_value(uri, &root)?;
        match value.kind {
            ValueKind::Table(map) => Ok(map),

            _ => Ok(Map::new()),
        }
    }

    fn from_yaml_value(
        uri: Option<&String>,
        value: &yaml::Yaml,
    ) -> Result<Value, Box<dyn Error + Send + Sync>> {
        match *value {
            yaml::Yaml::String(ref value) => Ok(Value::new(uri, ValueKind::String(value.clone()))),
            yaml::Yaml::Real(ref value) => {
                // TODO: Figure out in what cases this can panic?
                value
                    .parse::<f64>()
                    .map_err(|_| {
                        Box::new(FloatParsingError(value.to_string())) as Box<(dyn Error + Send + Sync)>
                    })
                    .map(ValueKind::Float)
                    .map(|f| Value::new(uri, f))
            }
            yaml::Yaml::Integer(value) => Ok(Value::new(uri, ValueKind::I64(value))),
            yaml::Yaml::Boolean(value) => Ok(Value::new(uri, ValueKind::Boolean(value))),
            yaml::Yaml::Hash(ref table) => {
                let mut m = Map::new();
                for (key, value) in table {
                    if let Some(k) = key.as_str() {
                        m.insert(k.to_owned(), from_yaml_value(uri, value)?);
                    }
                    // TODO: should we do anything for non-string keys?
                }
                Ok(Value::new(uri, ValueKind::Table(m)))
            }
            yaml::Yaml::Array(ref array) => {
                let mut l = Vec::new();

                for value in array {
                    l.push(from_yaml_value(uri, value)?);
                }

                Ok(Value::new(uri, ValueKind::Array(l)))
            }

            // 1. Yaml NULL
            // 2. BadValue – It shouldn't be possible to hit BadValue as this only happens when
            //               using the index trait badly or on a type error but we send back nil.
            // 3. Alias – No idea what to do with this and there is a note in the lib that its
            //            not fully supported yet anyway
            _ => Ok(Value::new(uri, ValueKind::Nil)),
        }
    }

    #[derive(Debug, Copy, Clone)]
    struct MultipleDocumentsError(usize);

    impl fmt::Display for MultipleDocumentsError {
        fn fmt(&self, format: &mut fmt::Formatter) -> fmt::Result {
            write!(format, "Got {} YAML documents, expected 1", self.0)
        }
    }

    impl Error for MultipleDocumentsError {
        fn description(&self) -> &str {
            "More than one YAML document provided"
        }
    }

    #[derive(Debug, Clone)]
    struct FloatParsingError(String);

    impl fmt::Display for FloatParsingError {
        fn fmt(&self, format: &mut fmt::Formatter) -> fmt::Result {
            write!(format, "Parsing {} as floating point number failed", self.0)
        }
    }

    impl Error for FloatParsingError {
        fn description(&self) -> &str {
            "Floating point number parsing failed"
        }
    }