types.rs

use std::collections::HashMap;
use std::hash::Hasher;
use std::rc::Rc;
use std::cell::{Cell, RefCell};
use std::fmt;
use std::error::Error;
use std::fmt::Display;
use std::str::FromStr;
use std::borrow::Cow;
use internals::parser::Parser;
use nom::IResult;

/// Conveys the result of a parse operation on a TOML document
#[derive(Debug, Eq, PartialEq, Clone)]
pub enum ParseResult<'a> {
  /// The entire input was parsed without error.
  Full,
  /// The entire input was parsed, but there were errors. Contains an `Rc<RefCell<Vec>>` of `ParseError`s.
  FullError(Rc<RefCell<Vec<ParseError<'a>>>>),
  /// Part of the input was parsed successfully without any errors. Contains a `Cow<str>`, with the leftover, unparsed
  /// input, the line number and column (currently column reporting is unimplemented and will always report `0`) where
  /// parsing stopped.
  Partial(Cow<'a, str>, usize, usize),
  /// Part of the input was parsed successfully with errors. Contains a `Cow<str>`, with the leftover, unparsed input,
  /// the line number and column (currently column reporting is unimplemented and will always report `0`) where parsing
  /// stopped, and an `Rc<RefCell<Vec>>` of `ParseError`s.
  PartialError(Cow<'a, str>, usize, usize, Rc<RefCell<Vec<ParseError<'a>>>>),
  /// The parser failed to parse any of the input as a complete TOML document. Contains the line number and column
  /// (currently column reporting is unimplemented and will always report `0`) where parsing stopped.
  Failure(usize, usize),
}

/// Represents a non-failure error encountered while parsing a TOML document.
#[derive(Debug, Eq, PartialEq, Clone)]
pub enum ParseError<'a> {
  /// An `Array` containing different types was encountered. Contains the `String` key that points to the `Array` and
  /// the line number and column (currently column reporting is unimplemented and will always report `0`) where the
  /// `Array` was found. The `Array` can be retrieved and/or changed by its key using `TOMLParser::get_value` and
  /// `TOMLParser::set_value` methods.
  MixedArray(String, usize, usize),
  /// A duplicate key was encountered. Contains the `String` key that was duplicated in the document, the line number
  /// and column (currently column reporting is unimplemented and will always report `0`) where the duplicate key was
  /// found, and the `Value` that the key points to.
  DuplicateKey(String, usize, usize, Value<'a>),
  /// An invalid table was encountered. Either the key\[s\] that make up the table are invalid or a duplicate table was
  /// found. Contains the `String` key of the invalid table, the line number and column (currently column reporting is
  /// unimplemented and will always report `0`) where the invalid table was found, `RefCell<HashMap<String, Value>>`
  /// that contains all the keys and values belonging to that table.
  InvalidTable(String, usize, usize, RefCell<HashMap<String, Value<'a>>>),
  /// An invalid `DateTime` was encountered. This could be a `DateTime` with:
  ///
  /// * 0 for year
  /// * 0 for month or greater than 12 for month
  /// * 0 for day or greater than, 28, 29, 30, or 31 for day depending on the month and if the year is a leap year
  /// * Greater than 23 for hour
  /// * Greater than 59 for minute
  /// * Greater than 59 for second
  /// * Greater than 23 for offset hour
  /// * Greater than 59 for offset minute
  ///
  /// Contains the `String` key of the invalid `DateTime`, the line number and column (currently column reporting is
  /// unimplemented and will always report `0`) where the invalid `DateTime` was found, and a Cow<str> containing the
  /// invalid `DateTime` string.
  InvalidDateTime(String, usize, usize, Cow<'a, str>),
  /// *Currently unimplemented*. Reserved for future use when an integer overflow is detected.
  IntegerOverflow(String, usize, usize, Cow<'a, str>),
  /// *Currently unimplemented*. Reserved for future use when an integer underflow is detected.
  IntegerUnderflow(String, usize, usize, Cow<'a, str>),
  /// *Currently unimplemented*. Reserved for future use when an invalid integer representation is detected.
  InvalidInteger(String, usize, usize, Cow<'a, str>),
  /// *Currently unimplemented*. Reserved for future use when a float value of infinity is detected.
  Infinity(String, usize, usize, Cow<'a, str>),
  /// *Currently unimplemented*. Reserved for future use when a float value of negative infinity is detected.
  NegativeInfinity(String, usize, usize, Cow<'a, str>),
  /// *Currently unimplemented*. Reserved for future use when a float string conversion to an `f64` would result in a loss
  /// of precision.
  LossOfPrecision(String, usize, usize, Cow<'a, str>),
  /// *Currently unimplemented*. Reserved for future use when an invalid float representation is detected.
  InvalidFloat(String, usize, usize, Cow<'a, str>),
  /// *Currently unimplemented*. Reserved for future use when an invalid `true` or `false` string is detected.
  InvalidBoolean(String, usize, usize, Cow<'a, str>),
  /// *Currently unimplemented*. Reserved for future use when an invalid string representation is detected.
  InvalidString(String, usize, usize, Cow<'a, str>, StrType),
  /// *Currently unimplemented*. Reserved for future use when new error types are added without resorting to a breaking
  /// change.
  GenericError(String, usize, usize, Option<Cow<'a, str>>, String),
}

// Represents the 7 different types of values that can exist in a TOML document.
#[derive(Debug, PartialEq, Eq, Clone)]
pub enum Value<'a> {
  /// An integer value. Contains a `Cow<str>` representing the integer since integers can contain underscores.
  Integer(Cow<'a, str>),
  /// A float value. Contains a `Cow<str>` representing the float since floats can be formatted many different ways and
  /// can contain underscores.
  Float(Cow<'a, str>),
  /// A boolean value. Contains a `bool` value since only `true` and `false` are allowed.
  Boolean(bool),
  /// A `DateTime` value. Contains a `DateTime` struct that has a date and optionally a time, fractional seconds, and
  /// offset from UTC.
  DateTime(DateTime<'a>),
  /// A string value. Contains a `Cow<str>` with the string contents (without quotes) and `StrType` indicating whether
  /// the string is a basic string, multi-line basic string, literal string or multi-line literal string.
  String(Cow<'a, str>, StrType),
  /// An array value. Contains an `Rc<Vec>` of `Value`s contained in the `Array`.
  Array(Rc<Vec<Value<'a>>>),
  /// An inline table value. Contains an `Rc<Vec>` of tuples that contain a `Cow<str>` representing a key, and `Value`
  /// that the key points to.
  InlineTable(Rc<Vec<(Cow<'a, str>, Value<'a>)>>)
}

/// Represents the 4 different types of strings that are allowed in TOML documents.
#[derive(Debug, Eq, PartialEq, Copy, Clone)]
pub enum StrType {
  /// String is a basic string.
  Basic,
  /// String is a multi-line basic string.
  MLBasic,
  /// String is a literal string.
  Literal,
  /// String is a multi-line literal string.
  MLLiteral,
}

/// Represents the child keys of a key in a parsed TOML document.
#[derive(Debug, Eq, PartialEq, Clone)]
pub enum Children {
  /// Contains a `Cell<usize>` with the amount of child keys the key has. The key has children that are indexed with an
  /// integer starting at 0. `Array`s and array of tables use integer for their child keys. For example:
  ///
  /// ```text
  /// Array = ["A", "B", "C", "D", "E"]
  /// [[array_of_table]]
  /// key = "val 1"
  /// [[array_of_table]]
  /// key = "val 2"
  /// [[array_of_table]]
  /// key = "val 3"
  /// ```
  ///
  /// "Array" has 5 children. The key of "D" is "Array[3]" because it is fourth element in "Array" and indexing starts
  /// at 0.
  /// "array_of_table" has 3 children. The key of "val 3" is "array_of_table[2].key" because it is in the third
  /// sub-table of "array_of_table" and indexing starts at 0.
  Count(Cell<usize>),
  /// Contains a `RefCell<Vec>` of `String`s with every sub-key of the key. The key has children that are indexed with a
  /// sub-key. Tables and inline-tables use sub-keys for their child keys. For example:
  ///
  /// ```text
  /// InlineTable = {subkey1 = "A", subkey2 = "B"}
  /// [table]
  /// a_key = "val 1"
  /// b_key = "val 2"
  /// c_key = "val 3"
  /// ```
  ///
  /// "InlineTable" has 2 children, "subkey1" and "subkey2". The key of "B" is "InlineTable.subkey2".
  /// "table" has 3 children, "a_key", "b_key", and "c_key". The key of "val 3" is "table.c_key".
  Keys(RefCell<Vec<String>>)
}

/// Contains convenience functions to combine base keys with child keys to make a full key.
impl Children {

  /// Combines string type `base_key` with a string type `child_key` to form a full key.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::TOMLParser;
  /// use tomllib::types::Children;
  /// let toml_doc = r#"
  /// [dependencies]
  /// nom = {version = "^1.2.0", features = ["regexp"]}
  /// regex = {version = "^0.1.48"}
  /// log = {version = "^0.3.5"}
  /// "#;
  /// let parser = TOMLParser::new();
  /// let (parser, result) = parser.parse(toml_doc);
  /// let deps = parser.get_children("dependencies");
  /// if let &Children::Keys(ref subkeys) = deps.unwrap() {
  ///   assert_eq!("dependencies.nom",
  ///     Children::combine_keys("dependencies", &subkeys.borrow()[0]));
  /// }
  /// ```
  pub fn combine_keys<S>(base_key: S, child_key: S) -> String where S: Into<String> {
    let mut full_key;
    let base = base_key.into();
    let child = child_key.into();
    if base != "" {
      full_key = base.clone();
      full_key.push('.');
      full_key.push_str(&child);
    } else {
      full_key = child.clone();
    }
    return full_key;
  }

  /// Combines string type `base_key` with an integer type `child_key` to form a full key.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::TOMLParser;
  /// use tomllib::types::Children;
  /// let toml_doc = r#"
  /// keywords = ["toml", "parser", "encode", "decode", "nom"]
  /// "#;
  /// let parser = TOMLParser::new();
  /// let (parser, result) = parser.parse(toml_doc);
  /// let kw = parser.get_children("keywords");
  /// if let &Children::Count(ref subkeys) = kw.unwrap() {
  ///   assert_eq!("keywords[4]", Children::combine_keys_index("keywords", subkeys.get() - 1));
  /// }
  /// # else {
  /// #  assert!(false, "{:?}", kw.unwrap());
  /// # }
  /// ```
  pub fn combine_keys_index<S>(base_key: S, child_key: usize) -> String where S: Into<String> {
    return format!("{}[{}]", base_key.into(), child_key);
  }

  /// Combines string type `base_key` with all subkeys of an instance of `Children` to form a `Vec` of full keys
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::TOMLParser;
  /// use tomllib::types::Children;
  /// let toml_doc = r#"
  /// keywords = ["toml", "parser"]
  /// numbers = {first = 1, second = 2}
  /// "#;
  /// let parser = TOMLParser::new();
  /// let (parser, result) = parser.parse(toml_doc);
  /// let kw = parser.get_children("keywords");
  /// assert_eq!(vec!["keywords[0]".to_string(), "keywords[1]".to_string()],
  ///   kw.unwrap().combine_child_keys("keywords"));
  /// let num = parser.get_children("numbers");
  /// assert_eq!(vec!["numbers.first".to_string(), "numbers.second".to_string()],
  ///   num.unwrap().combine_child_keys("numbers"));
  /// ```
  pub fn combine_child_keys<S>(&self, base_key: S) -> Vec<String> where S: Into<String> {
    let mut all_keys = vec![];
    let base = base_key.into();
    match self {
      &Children::Count(ref c) => {
        for i in 0..c.get() {
          all_keys.push(format!("{}[{}]", base, i));
        }
      },
      &Children::Keys(ref hs_rc) => {
        for subkey in hs_rc.borrow().iter() {
          if base != "" {
            let mut full_key = base.clone();
            full_key.push('.');
            full_key.push_str(&subkey);
            all_keys.push(full_key);
          } else {
            all_keys.push(subkey.clone());
          }
        }
      },
    }
    return all_keys;
  }
}

/// Formats a `Value` for display. Uses default rust formatting for for `i64` for `Integer`s, `f64` for `Float`s, bool
/// for `Boolean`s. The default formatting for `Array`s and `InlineTable`s is No whitespace after/before
/// opening/closing braces, no whitespace before and one space after all commas, no comments on the same line as the
/// `Array` or `InlineTable`, and one space before and after an equals sign in an `InlineTable`.
impl<'a> Display for Value<'a> {
  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
    match self {
      &Value::Integer(ref v) | &Value::Float(ref v) =>
        write!(f, "{}", v),
      &Value::Boolean(ref b) => write!(f, "{}", b),
      &Value::DateTime(ref v) => write!(f, "{}", v),
      &Value::Array(ref arr) => {
        try!(write!(f, "["));
        for i in 0..arr.len() - 1 {
          try!(write!(f, "{}, ", arr[i]));
        }
        if arr.len() > 0 {
          try!(write!(f, "{}", arr[arr.len()-1]));
        }
        write!(f, "]")
      },
      &Value::String(ref s, ref t) => {
        match t {
          &StrType::Basic => write!(f, "\"{}\"", s),
          &StrType::MLBasic => write!(f, "\"\"\"{}\"\"\"", s),
          &StrType::Literal => write!(f, "'{}'", s),
          &StrType::MLLiteral =>  write!(f, "'''{}'''", s),
        }
      },
      &Value::InlineTable(ref it) => {
        try!(write!(f, "{{"));
        for i in 0..it.len() - 1 {
          try!(write!(f, "{} = {}, ", it[i].0, it[i].1));
        }
        if it.len() > 0 {
          try!(write!(f, "{} = {}", it[it.len()-1].0, it[it.len()-1].1));
        }
        write!(f, "}}")
      }
    }
  }
}

impl<'a> Value<'a> {

  /// Convenience function for creating an `Value::Integer` from an `i64`. Cannot fail since `i64` maps directly onto
  /// TOML integers.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::Value;
  ///
  /// assert_eq!(Value::Integer("100".into()), Value::int(100));
  /// ```
  pub fn int(int: i64) -> Value<'a> {
    Value::Integer(format!("{}", int).into())
  }

  /// Convenience function for creating an `Value::Integer` from an string type. Returns `Ok(Integer)` on success and
  /// `Err(TOMLError)` on failure.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::Value;
  ///
  /// assert_eq!(Value::Integer("200".into()), Value::int_from_str("200").unwrap());
  /// ```
  pub fn int_from_str<S>(int: S) -> Result<Value<'a>, TOMLError> where S: Into<String> + Clone {
    let result = Value::Integer(int.clone().into().into());
    if result.validate() {
      return Result::Ok(result);
    } else {
      return Result::Err(TOMLError::new(format!("Error parsing int. Argument: {}", int.into())));
    }
  }

  /// Convenience function for creating a `Value::Float` from a `f64`. Cannot fail since `f64` maps directly onto TOML
  /// floats.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::Value;
  ///
  /// assert_eq!(Value::Float("300.3".into()), Value::float(300.3));
  /// ```
  pub fn float(float: f64) -> Value<'a> {
    Value::Float(format!("{}", float).into())
  }

  /// Convenience function for creating a `Value::Float` from an string type. Returns `Ok(Float)` on success and
  /// `Err(TOMLError)`
  /// on failure.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::Value;
  ///
  /// assert_eq!(Value::Float("400.4".into()), Value::float_from_str("400.4").unwrap());
  /// ```
  pub fn float_from_str<S>(float: S) -> Result<Value<'a>, TOMLError> where S: Into<String> + Clone {
    let result = Value::Float(float.clone().into().into());
    if result.validate() {
      return Result::Ok(result);
    } else {
      return Result::Err(TOMLError::new(format!("Error parsing float. Argument: {}", float.into())));
    }
  }

  /// Convenience function for creating a `Value::Boolean` from a `bool`. Cannot fail since `bool` maps directly onto
  /// TOML booleans.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::Value;
  ///
  /// assert_eq!(Value::Boolean(true), Value::bool(true));
  /// ```
  pub fn bool(b: bool) -> Value<'a> {
      Value::Boolean(b)
  }
  pub fn bool_from_str<S>(b: S) -> Result<Value<'a>, TOMLError> where S: Into<String> + Clone {
    let lower = b.clone().into().to_lowercase();
    if lower == "true" {
      Result::Ok(Value::Boolean(true))
    } else if lower == "false" {
      Result::Ok(Value::Boolean(false))
    } else {
      return Result::Err(TOMLError::new(
        format!("Error parsing bool. Argument: {}", b.into())
      ))
    }
  }

  /// Convenience function for creating a `Value::DateTime` containing only a date from integer values. Returns
  /// `Ok(DateTime)` on success and `Err(TOMLError)` on failure.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::{Value, DateTime, Date};
  ///
  /// assert_eq!(Value::DateTime(DateTime::new(Date::from_str("2010", "04", "10").unwrap(), None)),
  ///   Value::date_from_int(2010, 4, 10).unwrap());
  /// ```
  pub fn date_from_int(year: usize, month: usize, day: usize) -> Result<Value<'a>, TOMLError> {
    let y = format!("{:0>4}", year);
    let m = format!("{:0>2}", month);
    let d = format!("{:0>2}", day);
    match Date::from_str(y, m, d) {
      Ok(date) => {
        Ok(Value::DateTime(DateTime::new(date, None)))
      },
      Err(error) => Err(error),
    }
  }

  /// Convenience function for creating a `Value::DateTime` containing only a date from string values. Returns
  /// `Ok(DateTime)` on success and `Err(TOMLError)` on failure.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::{Value, DateTime, Date};
  ///
  /// assert_eq!(Value::DateTime(DateTime::new(Date::from_str("2011", "05", "11").unwrap(), None)),
  ///   Value::date_from_str("2011", "05", "11").unwrap());
  /// ```
  pub fn date_from_str<S>(year: S, month: S, day: S) -> Result<Value<'a>, TOMLError> where S: Into<String> + Clone {
    match Date::from_str(year.clone().into(), month.clone().into(), day.clone().into()) {
      Ok(date) => {
        Ok(Value::DateTime(DateTime::new(date, None)))
      },
      Err(error) => Err(error),
    }
  }

  /// Convenience function for creating a `Value::DateTime` containing a date and time from integer values. Returns
  /// `Ok(DateTime)` on success and `Err(TOMLError)` on failure.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::{Value, DateTime, Date, Time};
  ///
  /// assert_eq!(Value::DateTime(DateTime::new(Date::from_str("2010", "04", "10").unwrap(),
  ///   Some(Time::from_str("01", "02", "03", None, None).unwrap()))),
  ///   Value::datetime_from_int(2010, 4, 10, 1, 2, 3).unwrap());
  /// ```
  pub fn datetime_from_int(year: usize, month: usize, day: usize, hour: usize, minute: usize, second: usize) -> Result<Value<'a>, TOMLError> {
    let y = format!("{:0>4}", year);
    let m = format!("{:0>2}", month);
    let d = format!("{:0>2}", day);
    let h = format!("{:0>2}", hour);
    let min = format!("{:0>2}", minute);
    let s = format!("{:0>2}", second);
    match Date::from_str(y, m, d) {
      Ok(date) => {
        match Time::from_str(h, min, s, None, None) {
          Ok(time) => Ok(Value::DateTime(DateTime::new(date, Some(time)))),
          Err(error) => Err(error),
        }
      },
      Err(error) => Err(error),
    }
  }

  /// Convenience function for creating a `Value::DateTime` containing a date and time from string values. Returns
  /// `Ok(DateTime)` on success and `Err(TOMLError)` on failure.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::{Value, DateTime, Date, Time};
  ///
  /// assert_eq!(Value::DateTime(DateTime::new(Date::from_str("2011", "05", "11").unwrap(),
  ///   Some(Time::from_str("02", "03", "04", None, None).unwrap()))),
  ///   Value::datetime_from_str("2011", "05", "11", "02", "03", "04").unwrap());
  /// ```
  pub fn datetime_from_str<S>(year: S, month: S, day: S, hour: S, minute: S, second: S) -> Result<Value<'a>, TOMLError> where S: Into<String> + Clone {
    match Date::from_str(year.clone().into(), month.clone().into(), day.clone().into()) {
      Ok(date) => {
        match Time::from_str(hour.clone().into(), minute.clone().into(), second.clone().into(), None, None) {
          Ok(time) => Ok(Value::DateTime(DateTime::new(date, Some(time)))),
          Err(error) => Err(error),
        }
      },
      Err(error) => Err(error),
    }
  }

  /// Convenience function for creating a `Value::DateTime` containing a date and time with fractional seconds from
  /// integer values. Returns `Ok(DateTime)` on success and `Err(TOMLError)` on failure. Note, you can't represent
  /// leading zeros on the fractional part this way for example: `2016-03-15T08:05:22.00055` is not possible using this
  /// function.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::{Value, DateTime, Date, Time};
  ///
  /// assert_eq!(Value::DateTime(DateTime::new(Date::from_str("2010", "04", "10").unwrap(),
  ///   Some(Time::from_str("01", "02", "03", Some("5432".into()), None).unwrap()))),
  ///   Value::datetime_frac_from_int(2010, 4, 10, 1, 2, 3, 5432).unwrap());
  /// ```
  pub fn datetime_frac_from_int(year: usize, month: usize, day: usize, hour: usize, minute: usize, second: usize, frac: usize) -> Result<Value<'a>, TOMLError> {
    let y = format!("{:0>4}", year);
    let m = format!("{:0>2}", month);
    let d = format!("{:0>2}", day);
    let h = format!("{:0>2}", hour);
    let min = format!("{:0>2}", minute);
    let s = format!("{:0>2}", second);
    let f = format!("{}", frac);
    match Date::from_str(y, m, d) {
      Ok(date) => {
        match Time::from_str(h, min, s, Some(f), None) {
          Ok(time) => Ok(Value::DateTime(DateTime::new(date, Some(time)))),
          Err(error) => Err(error),
        }
      },
      Err(error) => Err(error),
    }
  }

  /// Convenience function for creating a `Value::DateTime` containing a date and time with fractional seconds from
  /// string values. Returns `Ok(DateTime)` on success and `Err(TOMLError)` on failure.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::{Value, DateTime, Date, Time};
  ///
  /// assert_eq!(Value::DateTime(DateTime::new(Date::from_str("2011", "05", "11").unwrap(),
  ///   Some(Time::from_str("02", "03", "04", Some("0043".into()), None).unwrap()))),
  ///   Value::datetime_frac_from_str("2011", "05", "11", "02", "03", "04", "0043").unwrap());
  /// ```
  pub fn datetime_frac_from_str<S>(year: S, month: S, day: S, hour: S, minute: S, second: S, frac: S) -> Result<Value<'a>, TOMLError> where S: Into<String> + Clone{
    match Date::from_str(year.clone().into(), month.clone().into(), day.clone().into()) {
      Ok(date) => {
        match Time::from_str(hour.clone().into(), minute.clone().into(), second.clone().into(), Some(frac.clone().into()), None) {
          Ok(time) => Ok(Value::DateTime(DateTime::new(date, Some(time)))),
          Err(error) => Err(error),
        }
      },
      Err(error) => Err(error),
    }
  }

  /// Convenience function for creating a `Value::DateTime` containing a date and time with a timezone offset from UTC
  /// from integer values, except for the plus/minus sign which is passed as a char `'+'` or `'-'`. Returns
  /// `Ok(DateTime)` on success and `Err(TOMLError)` on failure.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::{Value, DateTime, Date, Time, TimeOffset, TimeOffsetAmount};
  ///
  /// assert_eq!(Value::DateTime(DateTime::new(Date::from_str("2010", "04", "10").unwrap(),
  ///   Some(Time::from_str("01", "02", "03", None, Some(TimeOffset::Time(TimeOffsetAmount::from_str(
  ///     "+", "08", "00"
  ///   ).unwrap()))).unwrap()))),
  ///   Value::datetime_offset_from_int(2010, 4, 10, 1, 2, 3, '+', 8, 0).unwrap());
  /// ```
  pub fn datetime_offset_from_int(year: usize, month: usize, day: usize, hour: usize, minute: usize, second: usize, posneg: char, off_hour: usize, off_minute: usize) -> Result<Value<'a>, TOMLError> {
    let y = format!("{:0>4}", year);
    let m = format!("{:0>2}", month);
    let d = format!("{:0>2}", day);
    let h = format!("{:0>2}", hour);
    let min = format!("{:0>2}", minute);
    let s = format!("{:0>2}", second);
    let oh = format!("{:0>2}", off_hour);
    let omin = format!("{:0>2}", off_minute);
    let mut pn = "".to_string();
    pn.push(posneg);
    match Date::from_str(y, m, d) {
      Ok(date) => {
        match TimeOffsetAmount::from_str(pn, oh, omin) {
          Ok(offset) => {
            match Time::from_str(h, min, s, None, Some(TimeOffset::Time(offset))) {
              Ok(time) => Ok(Value::DateTime(DateTime::new(date, Some(time)))),
              Err(error) => Err(error),
            }
          },
          Err(error) => Result::Err(error),
        }
      },
      Err(error) => Err(error),
    }
  }

  /// Convenience function for creating a `Value::DateTime` containing a date and time with a timezone offset from UTC
  /// from string values. Returns `Ok(DateTime)` on success and `Err(TOMLError)` on failure.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::{Value, DateTime, Date, Time, TimeOffset, TimeOffsetAmount};
  ///
  /// assert_eq!(Value::DateTime(DateTime::new(Date::from_str("2011", "05", "11").unwrap(),
  ///   Some(Time::from_str("02", "03", "04", None, Some(TimeOffset::Time(TimeOffsetAmount::from_str(
  ///     "+", "09", "30"
  ///   ).unwrap()))).unwrap()))),
  ///   Value::datetime_offset_from_str("2011", "05", "11", "02", "03", "04", "+", "09", "30").unwrap());
  /// ```
  pub fn datetime_offset_from_str<S>(year: S, month: S, day: S, hour: S, minute: S, second: S, posneg: S, off_hour: S, off_minute: S) -> Result<Value<'a>, TOMLError> where S: Into<String> + Clone{
    match Date::from_str(year.clone().into(), month.clone().into(), day.clone().into()) {
      Ok(date) => {
        match TimeOffsetAmount::from_str(posneg.clone().into(), off_hour.clone().into(), off_minute.clone().into()) {
          Ok(offset) => {
            match Time::from_str(hour.clone().into(), minute.clone().into(), second.clone().into(), None, Some(
                    TimeOffset::Time(offset)
                  )) {
              Ok(time) => Ok(Value::DateTime(DateTime::new(date, Some(time)))),
              Err(error) => Err(error),
            }
          },
          Err(error) => Result::Err(error),
        }
      },
      Err(error) => Err(error),
    }
  }

  /// Convenience function for creating a `Value::DateTime` containing a date and time with a timezone of Zulu from
  /// integer values. Returns Ok(DateTime)` on success and `Err(TOMLError)` on failure.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::{Value, DateTime, Date, Time, TimeOffset};
  ///
  /// assert_eq!(Value::DateTime(DateTime::new(Date::from_str("2010", "04", "10").unwrap(),
  ///   Some(Time::from_str("01", "02", "03", None, Some(TimeOffset::Zulu)).unwrap()))),
  ///   Value::datetime_zulu_from_int(2010, 4, 10, 1, 2, 3).unwrap());
  /// ```
  pub fn datetime_zulu_from_int(year: usize, month: usize, day: usize, hour: usize, minute: usize, second: usize) -> Result<Value<'a>, TOMLError> {
    let y = format!("{:0>4}", year);
    let m = format!("{:0>2}", month);
    let d = format!("{:0>2}", day);
    let h = format!("{:0>2}", hour);
    let min = format!("{:0>2}", minute);
    let s = format!("{:0>2}", second);
    match Date::from_str(y, m, d) {
      Ok(date) => {
        match Time::from_str(h, min, s, None, Some(TimeOffset::Zulu)) {
          Ok(time) => Ok(Value::DateTime(DateTime::new(date, Some(time)))),
          Err(error) => Err(error),
        }
      },
      Err(error) => Err(error),
    }
  }

  /// Convenience function for creating a `Value::DateTime` containing a date and time with a timezone of Zulu from
  /// string values. Returns `Ok(DateTime)` on success and `Err(TOMLError)` on failure.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::{Value, DateTime, Date, Time, TimeOffset};
  ///
  /// assert_eq!(Value::DateTime(DateTime::new(Date::from_str("2011", "05", "11").unwrap(),
  ///   Some(Time::from_str("02", "03", "04", None, Some(TimeOffset::Zulu)).unwrap()))),
  ///   Value::datetime_zulu_from_str("2011", "05", "11", "02", "03", "04").unwrap());
  /// ```
  pub fn datetime_zulu_from_str<S>(year: S, month: S, day: S, hour: S, minute: S, second: S) -> Result<Value<'a>, TOMLError> where S: Into<String> + Clone {
    match Date::from_str(year.clone().into(), month.clone().into(), day.clone().into()) {
      Ok(date) => {
        match Time::from_str(hour.clone().into(), minute.clone().into(), second.clone().into(), None, Some(
                TimeOffset::Zulu
              )) {
          Ok(time) => Ok(Value::DateTime(DateTime::new(date, Some(time)))),
          Err(error) => Err(error),
        }
      },
      Err(error) => Err(error),
    }
  }

  /// Convenience function for creating a `Value::DateTime` containing a date and time with fractional seconds and a
  /// timezone of Zulu from integer values, except for the plus/minus sign which is passed as a string value `"+"` or
  /// "-"`. Returns `Ok(DateTime)` on success and `Err(TOMLError)` on failure. Note, you can't represent leading zeros
  /// on the fractional part this way for example: `2016-03-15T08:05:22.00055Z` is not possible using this function.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::{Value, DateTime, Date, Time, TimeOffset};
  ///
  /// assert_eq!(Value::DateTime(DateTime::new(Date::from_str("2010", "04", "10").unwrap(),
  ///   Some(Time::from_str("01", "02", "03", Some("5678".into()), Some(TimeOffset::Zulu)).unwrap()))),
  ///   Value::datetime_full_zulu_from_int(2010, 4, 10, 1, 2, 3, 5678).unwrap());
  /// ```
  pub fn datetime_full_zulu_from_int(year: usize, month: usize, day: usize, hour: usize, minute: usize, second: usize, frac: u64) -> Result<Value<'a>, TOMLError> {
    let y = format!("{:0>4}", year);
    let m = format!("{:0>2}", month);
    let d = format!("{:0>2}", day);
    let h = format!("{:0>2}", hour);
    let min = format!("{:0>2}", minute);
    let s = format!("{:0>2}", second);
    let f = format!("{}", frac);
    match Date::from_str(y, m, d) {
      Ok(date) => {
        match Time::from_str(h, min, s, Some(f), Some(TimeOffset::Zulu)) {
          Ok(time) => Ok(Value::DateTime(DateTime::new(date, Some(time)))),
          Err(error) => Err(error),
        }
      },
      Err(error) => Err(error),
    }
  }

  /// Convenience function for creating a `Value::DateTime` containing a date and time with fractional seconds and a
  /// timezone of Zulu from string values. Returns `Ok(DateTime)` on success and `Err(TOMLError)` on failure.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::{Value, DateTime, Date, Time, TimeOffset};
  ///
  /// assert_eq!(Value::DateTime(DateTime::new(Date::from_str("2011", "05", "11").unwrap(),
  ///   Some(Time::from_str("02", "03", "04", None, Some(TimeOffset::Zulu)).unwrap()))),
  ///   Value::datetime_zulu_from_str("2011", "05", "11", "02", "03", "04").unwrap());
  /// ```
  pub fn datetime_full_zulu_from_str<S>(year: S, month: S, day: S, hour: S, minute: S, second: S, frac: S) -> Result<Value<'a>, TOMLError> where S: Into<String> + Clone {
    match Date::from_str(year.clone().into(), month.clone().into(), day.clone().into()) {
      Ok(date) => {
        match Time::from_str(hour.clone().into(), minute.clone().into(), second.clone().into(), Some(frac.clone().into()), Some(
            TimeOffset::Zulu
          )) {
          Ok(time) => Ok(Value::DateTime(DateTime::new(date, Some(time)))),
          Err(error) => Err(error),
        }
      },
      Err(error) => Err(error),
    }
  }

  /// Convenience function for creating a `Value::DateTime` containing a date and time with fractional seconds and a
  /// timezone offset from UTC from integer values, except for the plus/minus sign which is passed as a char `"+"` or
  /// `"-"`. Returns `Ok(DateTime)` on success and `Err(TOMLError)` on failure. Note, you can't represent
  /// leading zeros on the fractional part this way for example: `2016-03-15T08:05:22.00055-11:00` is not possible using
  /// this function.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::{Value, DateTime, Date, Time, TimeOffset, TimeOffsetAmount};
  ///
  /// assert_eq!(Value::DateTime(DateTime::new(Date::from_str("2010", "04", "10").unwrap(),
  ///   Some(Time::from_str("01", "02", "03", Some("135".into()), Some(TimeOffset::Time(TimeOffsetAmount::from_str(
  ///     "-", "11", "00"
  ///   ).unwrap()))).unwrap()))),
  ///   Value::datetime_full_from_int(2010, 4, 10, 1, 2, 3, 135, '-', 11, 0).unwrap());
  /// ```
  pub fn datetime_full_from_int(year: usize, month: usize, day: usize, hour: usize, minute: usize, second: usize, frac: u64, posneg: char, off_hour: usize, off_minute: usize) -> Result<Value<'a>, TOMLError> {
    let y = format!("{:0>4}", year);
    let m = format!("{:0>2}", month);
    let d = format!("{:0>2}", day);
    let h = format!("{:0>2}", hour);
    let min = format!("{:0>2}", minute);
    let s = format!("{:0>2}", second);
    let f = format!("{}", frac);
    let oh = format!("{:0>2}", off_hour);
    let omin = format!("{:0>2}", off_minute);
    let mut pn = "".to_string();
    pn.push(posneg);
    match Date::from_str(y, m, d) {
      Ok(date) => {
        match TimeOffsetAmount::from_str(pn, oh, omin) {
          Ok(offset) => {
            match Time::from_str(h, min, s, Some(f), Some(TimeOffset::Time(offset))) {
              Ok(time) => Ok(Value::DateTime(DateTime::new(date, Some(time)))),
              Err(error) => Err(error),
            }
          },
          Err(error) => Err(error),
        }
      },
      Err(error) => Err(error),
    }
  }

  /// Convenience function for creating a `Value::DateTime` containing a date and time with fractional seconds and a
  /// timezone offset from UTC from string values. Returns `Ok(DateTime)` on success and `Err(TOMLError)` on failure.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::{Value, DateTime, Date, Time, TimeOffset, TimeOffsetAmount};
  ///
  /// assert_eq!(Value::DateTime(DateTime::new(Date::from_str("2011", "05", "11").unwrap(),
  ///   Some(Time::from_str("02", "03", "04", Some("0864".into()), Some(TimeOffset::Time(TimeOffsetAmount::from_str(
  ///     "+", "09", "30"
  ///   ).unwrap()))).unwrap()))),
  ///   Value::datetime_full_from_str("2011", "05", "11", "02", "03", "04", "0864","+", "09", "30").unwrap());
  /// ```
  pub fn datetime_full_from_str<S>(year: S, month: S, day: S, hour: S, minute: S, second: S, frac: S, posneg: S, off_hour: S, off_minute: S) -> Result<Value<'a>, TOMLError> where S: Into<String> + Clone {
    match Date::from_str(year.clone().into(), month.clone().into(), day.clone().into()) {
      Ok(date) => {
        match TimeOffsetAmount::from_str(posneg.clone().into(), off_hour.clone().into(), off_minute.clone().into()) {
          Ok(offset) => {
            match  Time::from_str(hour.clone().into(), minute.clone().into(), second.clone().into(), Some(frac.clone().into()), Some(
                TimeOffset::Time(offset)
              )) {
              Ok(time) => Ok(Value::DateTime(DateTime::new(date, Some(time)))),
              Err(error) => Err(error),
            }
          },
          Err(error) => Err(error),
        }
      },
      Err(error) => Err(error),
    }
  }

  /// Convenience function for creating a `Value::DateTime` from a sinle string value.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::{Value, DateTime, Date, Time, TimeOffset, TimeOffsetAmount};
  ///
  /// assert_eq!(Value::DateTime(DateTime::new(Date::from_str("2012", "06", "12").unwrap(),
  ///   Some(Time::from_str("02", "03", "04", Some("0864".into()), Some(TimeOffset::Time(TimeOffsetAmount::from_str(
  ///     "+", "10", "30"
  ///   ).unwrap()))).unwrap()))),
  ///   Value::datetime_parse("2012-06-12T02:03:04.0864+10:30").unwrap());
  /// ```
  pub fn datetime_parse<S>(dt: S) -> Result<Value<'a>, TOMLError> where S: Into<&'a str> {
    let datetime = dt.into();
    let p = Parser::new();
    match p.date_time(datetime) {
      (_, IResult::Done(i, o)) => {
        let result = Value::DateTime(o);
        if i.len() > 0 || !result.validate() {
          return Result::Err(TOMLError::new(format!("Error parsing string as datetime. Argument: {}", datetime)));
        } else {
          return Result::Ok(result);
        }
      },
      (_,_) => return Result::Err(TOMLError::new(format!("Error parsing string as datetime. Argument: {}", datetime))),
    }
  }

  /// Convenience function for creating a `Value::String` with `StrType::Basic`. Returns Ok() on success and Err() on
  /// failure.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::{Value, StrType};
  ///
  /// assert_eq!(Value::String("foobar".into(), StrType::Basic), Value::basic_string("foobar").unwrap());
  /// ```
  pub fn basic_string<S>(s: S) -> Result<Value<'a>, TOMLError> where S: Into<String> + Clone {
    let result = Value::String(s.clone().into().into(), StrType::Basic);
    if result.validate() {
      return Result::Ok(result);
    } else {
      return Result::Err(TOMLError::new(format!("Error parsing string as basic_string. Argument: {}", s.into())));
    }
  }

  /// Convenience function for creating a `Value::String` with `StrType::MLBasic`. Returns Ok() on success and Err() on
  /// failure.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::{Value, StrType};
  ///
  /// assert_eq!(Value::String("foo\nbar".into(), StrType::MLBasic), Value::ml_basic_string("foo\nbar").unwrap());
  /// ```
  pub fn ml_basic_string<S>(s: S) -> Result<Value<'a>, TOMLError> where S: Into<String> + Clone {
    let result = Value::String(s.clone().into().into(), StrType::MLBasic);
    if result.validate() {
      return Result::Ok(result);
    } else {
      return Result::Err(TOMLError::new(format!("Error parsing string as ml_basic_string. Argument: {}", s.into())));
    }
  }

  /// Convenience function for creating a `Value::String` with `StrType::Literal`. Returns Ok() on success and Err() on
  /// failure.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::{Value, StrType};
  ///
  /// assert_eq!(Value::String("\"foobar\"".into(), StrType::Literal), Value::literal_string("\"foobar\"").unwrap());
  /// ```
  pub fn literal_string<S>(s: S) -> Result<Value<'a>, TOMLError> where S: Into<String> + Clone {
    let result = Value::String(s.clone().into().into(), StrType::Literal);
    if result.validate() {
      return Result::Ok(result);
    } else {
      return Result::Err(TOMLError::new(format!("Error parsing string as literal_string. Argument: {}", s.into())));
    }
  }

  /// Convenience function for creating a `Value::String` with `StrType::MLLiteral`. Returns Ok() on success and Err()
  /// on failure.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::{Value, StrType};
  ///
  /// assert_eq!(Value::String("\"foo\nbar\"".into(), StrType::MLLiteral),
  ///   Value::ml_literal_string("\"foo\nbar\"").unwrap());
  /// ```
  pub fn ml_literal_string<S>(s: S) -> Result<Value<'a>, TOMLError> where S: Into<String> + Clone {
    let result = Value::String(s.clone().into().into(), StrType::MLLiteral);
    if result.validate() {
      return Result::Ok(result);
    } else {
      return Result::Err(TOMLError::new(format!("Error parsing string as ml_literal_string. Argument: {}", s.into())));
    }
  }

  /// Parses and validates a `Value`, returns true if the value is valid and false if it is invalid.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::{Value};
  ///
  /// assert!(!Value::Integer("_989_721_".into()).validate()); // Integers may have underscores but they must be
  ///                                                           // surrounded by digits
  /// assert!(Value::Float("7.62".into()).validate());
  /// ```
  pub fn validate(&self) -> bool{
    match self {
      &Value::Integer(ref s) => {
        let p = Parser::new();
        match p.integer(s) {
           (_, IResult::Done(_, _)) => true,
           (_,_) => false,
        }
      },
      &Value::Float(ref s) => {
        let p = Parser::new();
        match p.float(s) {
           (_, IResult::Done(_, _)) => true,
           (_,_) => false,
        }
      },
      &Value::DateTime(ref dt) => {dt.validate()},
      &Value::String(ref s, st) => {
        match st {
          StrType::Basic => {
            match Parser::quoteless_basic_string(s) {
              IResult::Done(i,_) => i.len() == 0,
              _ => false,
            }
          },
          StrType::MLBasic => {
            match Parser::quoteless_ml_basic_string(s) {
              IResult::Done(i,_) => i.len() == 0,
              _ => false,
            }
          },
          StrType::Literal => {
            match Parser::quoteless_literal_string(s) {
              IResult::Done(i,_) => i.len() == 0,
              _ => false,
            }
          },
          StrType::MLLiteral => {
            match Parser::quoteless_ml_literal_string(s) {
              IResult::Done(i,_) => i.len() == 0,
              _ => false,
            }
          },
        }
      },
      _ => true,
    }
  }
}

/// Error type returned by `Value` creation convenience functions on invalid input.
#[derive(Debug)]
pub struct TOMLError {
  message: String,
}

impl Error for TOMLError {

  /// Gives a description of the error encountered when validating input to a `Value` creation function.
  ///
  /// # Examples
  ///
  /// ```
  /// use std::error::Error;
  /// use tomllib::types::Value;
  ///
  /// if let Err(toml_err) = Value::basic_string("foo\n") {
  ///   println!("{}", toml_err.description());
  /// }
  /// # else {
  /// #   assert!(false);
  /// # }
  /// ```
  fn description(&self) -> &str {
    &self.message
  }

  /// Returns an `Error` that caused the current `Error`. Always returns `None`.
  fn cause(&self) -> Option<&Error> { None }
}

impl Display for TOMLError {
  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
    write!(f, "{}", self.message)
  }
}

impl TOMLError {
  fn new(msg: String) -> TOMLError {
    warn!("{}", msg);
    TOMLError{message: msg}
  }
}

/// Represents a plus sign or minus sign for positive and negative timezone offsets.
#[derive(Debug, Eq, PartialEq, Clone, Copy)]
pub enum PosNeg {
  /// A plus sign representing a positive timezone offset.
  Pos,
  /// A minus sign representing a negaive timezone offset.
  Neg,
}

impl Display for PosNeg {
  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
    match self {
      &PosNeg::Pos => write!(f, "+"),
      &PosNeg::Neg => write!(f, "-"),
    }

  }
}

/// Represents either a timezone of Zulu or or hour plus minute timezone offset from UTC.
#[derive(Debug, Eq, Clone)]
pub enum TimeOffset<'a> {
  // Timezone [Zulu](https://en.wikipedia.org/wiki/List_of_military_time_zones), also known as Greenwich Mean Time or
  // Coordinated Universal Time (UTC).
  Zulu,
  // Contains a `TimeOffsetAmount` with the hours and minutes offset from UTC.
  Time(TimeOffsetAmount<'a>),
}

impl<'a> PartialEq for TimeOffset<'a> {
  fn eq(&self, other: &TimeOffset<'a>) -> bool {
    match (self, other) {
      (&TimeOffset::Zulu, &TimeOffset::Zulu) => true,
      (&TimeOffset::Time(ref i), &TimeOffset::Time(ref j)) if(i == j) => true,
      _ => false
    }
  }
}

impl<'a> Display for TimeOffset<'a> {
  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
    match self {
      &TimeOffset::Zulu => write!(f, "Z"),
      &TimeOffset::Time(ref t) => write!(f, "{}", t),
    }
  }
}

impl<'a> TimeOffset<'a> {
  pub fn validate(&self) -> bool {
    match self {
      &TimeOffset::Zulu => return true,
      &TimeOffset::Time(ref amount) => return amount.validate(),
    }
  }
}

/// A positive or negative amount of hours and minutes offset from UTC.
#[derive(Debug, Eq, Clone)]
pub struct TimeOffsetAmount<'a> {
  /// Represents whether the offset is positive or negative.
  pub pos_neg: PosNeg,
  /// Represents the number of hours that time is offset from UTC.Must be 2 decimal digits between 0 23 inclusive.
  pub hour: Cow<'a, str>,
  /// Represents the number of minutes that time is offset from UTC. Must be 2 decimal digits between 0 59 inclusive.
  pub minute: Cow<'a, str>,
}

impl<'a> PartialEq for TimeOffsetAmount<'a> {
  fn eq(&self, other: &TimeOffsetAmount<'a>) -> bool {
    self.pos_neg == other.pos_neg &&
    self.hour == other.hour &&
    self.minute == other.minute
  }
}

impl<'a> Display for TimeOffsetAmount<'a> {
  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
    write!(f, "{}{}:{}", self.pos_neg, &self.hour, &self.minute)
  }
}

impl<'a> TimeOffsetAmount<'a> {

  /// Create a new `TimeOffsetAmount` from string type values. Returns `Ok()` on success and `Err()` on failure.
  ///
  /// # Examples
  /// ```
  /// use tomllib::types::TimeOffsetAmount;
  ///
  /// let offset = TimeOffsetAmount::from_str("-", "04", "00").unwrap();
  /// ```
  pub fn from_str<S>(pos_neg: S, hour: S, minute: S) -> Result<TimeOffsetAmount<'a>, TOMLError> where S: Into<String>{
    let pn = match pos_neg.into().as_ref() {
      "+" => PosNeg::Pos,
      "-" => PosNeg::Neg,
      _   => return Result::Err(TOMLError::new("pos_neg value is neither a '+' or a '-'.".to_string())),
    };
    let offset = TimeOffsetAmount{pos_neg: pn, hour: hour.into().into(), minute: minute.into().into()};
    if offset.validate() {
      return Result::Ok(offset);
    } else {
      return Result::Err(TOMLError::new("Error validating TimeOffsetAmount.".to_string()));
    }
  }

  /// Validates a created `TimeOffsetAmount`.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::{TimeOffsetAmount, PosNeg};
  ///
  /// let offset_wrong = TimeOffsetAmount{pos_neg: PosNeg::Pos, hour: "31".into(), minute: "30".into()};
  /// let offset_right = TimeOffsetAmount{pos_neg: PosNeg::Pos, hour: "07".into(), minute: "00".into()};
  /// assert!(!offset_wrong.validate());
  /// assert!(offset_right.validate());
  /// ```
  pub fn validate(&self) -> bool {
    if self.hour.len() != 2 || self.minute.len() != 2 {
      return false;
    }
    return self.validate_numbers();
   }

  fn validate_numbers(&self) -> bool {
    if let Ok(h) = usize::from_str(&self.hour) {
      if h > 23 {
        return false;
      }
    } else {
      return false;
    }
    if let Ok(m) = usize::from_str(&self.minute) {
      if m > 59 {
        return false;
      }
    } else {
      return false;
    }
    return true;
  }
}

/// Represents a date value.
// <year>-<month>-<day>
#[derive(Debug, Eq, Clone)]
pub struct Date<'a> {
  /// Represents the year of a date. Must be 4 decimal digits greater than 0".
  pub year: Cow<'a, str>,
  /// Represents the month of a date. Must be 2 decimal digits greater than 0 less than 13.
  pub month: Cow<'a, str>,
  /// Represents the day of a date. Must be 2 decimal digits greater than 0less than 28, 29, 30, or 31 depending on the
  /// month and whether the year is a leap year.
  pub day: Cow<'a, str>,
}

impl<'a> PartialEq for Date<'a> {
  fn eq(&self, other: &Date<'a>) -> bool {
    self.year == other.year &&
    self.month == other.month &&
    self.day == other.day
  }
}

impl<'a> Display for Date<'a> {
  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
    write!(f, "{}-{}-{}", self.year, self.month, self.day)
  }
}

impl<'a> Date<'a> {

  /// Create a new `Date` from string type values. Returns `Ok()` on success and `Err()` on failure.
  ///
  /// # Examples
  /// ```
  /// use tomllib::types::Date;
  ///
  /// let date = Date::from_str("1991", "09", "23").unwrap();
  /// ```
  pub fn from_str<S>(year: S, month: S, day: S) -> Result<Date<'a>, TOMLError> where S: Into<String> {
    let date = Date{year: year.into().into(), month: month.into().into(), day: day.into().into()};
    if date.validate() {
      Ok(date)
    } else {
      Err(TOMLError::new("Error validating Date.".to_string()))
    }
  }

  /// Validates a created `Date`.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::Date;
  ///
  /// let date_wrong = Date{year: "76563".into(), month: "10".into(), day: "20".into()};
  /// let date_right = Date{year: "1763".into(), month: "10".into(), day: "20".into()};
  /// assert!(!date_wrong.validate());
  /// assert!(date_right.validate());
  /// ```
  pub fn validate(&self) -> bool {
    if self.year.len() != 4 || self.month.len() != 2 || self.day.len() != 2 {
      return false;
    }
    return self.validate_numbers();
  }

  fn validate_numbers(&self) -> bool {
    if let Ok(y) = usize::from_str(&self.year) {
      if y == 0 || y > 9999{
        return false;
      }
      if let Ok(m) = usize::from_str(&self.month) {
        if m < 1 || m > 12 {
          return false;
        }
        if let Ok(d) = usize::from_str(&self.day) {
          if d < 1 {
            return false;
          }
          match m {
            2 => {
              let leap_year;
              if y % 4 != 0 {
                leap_year = false;
              } else if y % 100 != 0 {
                leap_year = true;
              } else if y % 400 != 0 {
                leap_year = false;
              } else {
                leap_year = true;
              }
              if leap_year && d > 29 {
                return false;
              } else if !leap_year && d > 28 {
                return false;
              }
            },
            1 | 3 | 5 | 7 | 8 | 10 | 12 => { if d > 31 { return false; } },
            _ => { if d > 30 { return false; } },
          }
        } else {
          return false;
        }
      } else {
        return false;
      }
    } else {
      return false;
    }
    return true;
  }
}

/// Represents the time part of a `DateTime` including optional fractional seconds and timezone offset.
#[derive(Debug, Eq, Clone)]
pub struct Time<'a> {
  /// Represents the hour of the time. Must be 2 decimal digits between 0 and 23 inclusive.
  pub hour: Cow<'a, str>,
  /// Represents the minute of the time. Must be 2 decimal digits between 0 and 59 inclusive.
  pub minute: Cow<'a, str>,
  /// Represent the second of the time. Must be 2 decimal digits between 0 and 59 inclusive.
  pub second: Cow<'a, str>,
  /// Optional fraction of a second of the time. Can be an arbitrary number of decimal digits.
  pub fraction: Option<Cow<'a, str>>,
  /// Optional time zone offset.
  pub offset: Option<TimeOffset<'a>>,
}

impl<'a> PartialEq for Time<'a> {
  fn eq(&self, other: &Time<'a>) -> bool {
    self.hour == other.hour &&
    self.minute == other.minute &&
    self.second == other.second &&
    self.fraction == other.fraction &&
    self.offset == other.offset
  }
}

impl<'a> Display for Time<'a> {
  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
    match (&self.fraction, &self.offset) {
      (&Some(ref frac), &Some(ref offset))  => write!(f, "T{}:{}:{}.{}{}", self.hour, self.minute, self.second, frac, offset),
      (&Some(ref frac), &None)              => write!(f, "T{}:{}:{}.{}", self.hour, self.minute, self.second, frac),
      (&None, &Some(ref offset))            => write!(f, "T{}:{}:{}{}", self.hour, self.minute, self.second, offset),
      (&None, &None)                        => write!(f, "T{}:{}:{}", self.hour, self.minute, self.second),
    }
  }
}

impl<'a> Time<'a> {

  /// Create a new `Time` from string type values. Returns `Ok()` on success and `Err()` on failure.
  ///
  /// # Examples
  /// ```
  /// use tomllib::types::Time;
  ///
  /// let time = Time::from_str("19", "33", "02", None, None).unwrap();
  /// ```
  pub fn from_str<S>(hour: S, minute: S, second: S, fraction: Option<S>, offset: Option<TimeOffset<'a>>)
    -> Result<Time<'a>, TOMLError> where S: Into<String> {
    if let Some(s) = fraction {
      let time = Time{hour: hour.into().into(), minute: minute.into().into(), second: second.into().into(),
        fraction: Some(s.into().into()), offset: offset};
      if time.validate() {
        return Ok(time);
      } else {
        return Err(TOMLError::new("Error validating Time.".to_string()));
      }
    } else {
      let time = Time{hour: hour.into().into(), minute: minute.into().into(), second: second.into().into(),
        fraction: None, offset: offset};
      if time.validate() {
        return Ok(time);
      } else {
        return Err(TOMLError::new("Error validating Time.".to_string()));
      }
    }
  }

  /// Validates a created `Time`.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::Time;
  ///
  /// let time_wrong = Time{hour: "23".into(), minute: "79".into(), second: "20".into(),
  ///   fraction: None, offset: None};
  /// let time_right = Time{hour: "11".into(), minute: "53".into(), second: "25".into(),
  ///   fraction: None, offset: None};
  /// assert!(!time_wrong.validate());
  /// assert!(time_right.validate());
  /// ```
  pub fn validate(&self) -> bool {
    if self.hour.len() != 2 || self.minute.len() != 2 || self.second.len() != 2 {
      return false;
    }
    return self.validate_numbers();
  }

  fn validate_numbers(&self) -> bool {
    if let Ok(h) = usize::from_str(&self.hour) {
      if h > 23 {
        return false;
      }
    } else {
      return false;
    }
    if let Ok(m) = usize::from_str(&self.minute) {
      if m > 59 {
        return false;
      }
    } else {
      return false;
    }
    if let Ok(s) = usize::from_str(&self.second) {
      if s > 59 {
        return false;
      }
    } else {
      return false;
    }
    if let Some(ref frac) = self.fraction {
      if u64::from_str(frac).is_err() {
        return false;
      }
    }
    if let Some(ref off) = self.offset {
      if !off.validate() {
        return false;
      }
    }
    return true;
  }
}

/// Represents a`DateTime` including the `Date` and optional `Time`
#[derive(Debug, Eq, Clone)]
pub struct DateTime<'a> {
  pub date: Date<'a>,
  pub time: Option<Time<'a>>,
}

impl<'a> PartialEq for DateTime<'a> {
  fn eq(&self, other: &DateTime<'a>) -> bool {
    self.date == other.date &&
    self.time == other.time
  }
}

impl<'a> Display for DateTime<'a> {
  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
    match &self.time {
      &Some(ref time) => write!(f, "{}{}", self.date, time),
      &None => write!(f, "{}", self.date),
    }
  }
}

// <hour>:<minute>:<second>(.<fraction>)?
impl<'a> DateTime<'a> {
  pub fn new(date: Date<'a>, time: Option<Time<'a>>) -> DateTime<'a> {
    DateTime{date: date, time: time}
  }

  /// Validates a created `DateTime`.
  ///
  /// # Examples
  ///
  /// ```
  /// use tomllib::types::{DateTime, Date};
  ///
  /// let dt_wrong = DateTime{ date: Date{ year: "53456".into(), month: "06".into(), day: "20".into() }, time: None};
  /// let dt_right = DateTime{ date: Date{ year: "1995".into(), month: "09".into(), day: "13".into() }, time: None};
  /// assert!(!dt_wrong.validate());
  /// assert!(dt_right.validate());
  /// ```
  pub fn validate(&self) -> bool {
    if self.date.validate() {
      if let Some(ref time) = self.time {
        return time.validate();
      }
    } else {
      return false;
    }
    return true;
  }
}

#[cfg(test)]
mod test {
  use std::cell::{Cell, RefCell};
  use std::rc::Rc;
  use types::{Children, Value, Date, Time, DateTime, TimeOffset, TimeOffsetAmount, StrType};

  #[test]
  fn test_combine_keys() {
    assert_eq!("foo.bar.baz".to_string(), Children::combine_keys("foo.bar", "baz"));
  }

  #[test]
  fn test_combine_keys_index() {
    assert_eq!("foo.bar[9]".to_string(), Children::combine_keys_index("foo.bar", 9));
  }

  #[test]
  fn test_combine_child_keys() {
    let kids = Children::Keys(RefCell::new(vec!["baz".to_string(), "qux".to_string(), "plugh".to_string(),
      "thud".to_string()]));
    assert_eq!(vec!["foo.bar.baz".to_string(), "foo.bar.qux".to_string(), "foo.bar.plugh".to_string(),
      "foo.bar.thud".to_string()], kids.combine_child_keys("foo.bar".to_string()));
  }

  #[test]
  fn test_combine_child_keys_empty_base() {
    let kids = Children::Keys(RefCell::new(vec!["baz".to_string(), "qux".to_string(), "plugh".to_string(),
      "thud".to_string()]));
    assert_eq!(vec!["baz".to_string(), "qux".to_string(), "plugh".to_string(),
      "thud".to_string()], kids.combine_child_keys("".to_string()));
  }

  #[test]
  fn test_combine_child_keys_index() {
    let kids = Children::Count(Cell::new(3));
    assert_eq!(vec!["foo.bar[0]".to_string(), "foo.bar[1]".to_string(), "foo.bar[2]".to_string()],
      kids.combine_child_keys("foo.bar".to_string()));
  }

  #[test]
  fn test_value_display() {
    let val_int = Value::Integer("7778877".into());
    let val_float = Value::Float("1929.345".into());
    let val_true = Value::Boolean(true);
    let val_false = Value::Boolean(false);
    let val_datetime = Value::DateTime(DateTime::new(Date::new_str("9999", "12", "31"), Some(Time::new_str(
      "23", "59", "59", Some("9999999"), Some(TimeOffset::Time(TimeOffsetAmount::new_str(
        "-", "00", "00"
      )))
    ))));
    let val_basic_str = Value::String("foobar1".into(), StrType::Basic);
    let val_literal_str = Value::String("foobar2".into(), StrType::Literal);
    let val_ml_basic_str = Value::String("foobar3".into(), StrType::MLBasic);
    let val_ml_literal_str = Value::String("foobar4".into(), StrType::MLLiteral);
    let val_array = Value::Array(Rc::new(vec![Value::Integer("3000".into()),
      Value::Array(Rc::new(vec![Value::Integer("40000".into()), Value::Float("50.5".into())])),
      Value::String("barbaz".into(), StrType::Literal)]));
    let val_inline_table = Value::InlineTable(Rc::new(vec![
      ("foo".into(), Value::Boolean(true)), ("bar".into(), Value::InlineTable(Rc::new(vec![
        ("baz".into(), Value::Boolean(false)), ("qux".into(), Value::Integer("2016".into())),
      ]))), ("plugh".into(), Value::Float("3333.444".into()))
    ]));

    assert_eq!("7778877", &format!("{}", val_int));
    assert_eq!("1929.345", &format!("{}", val_float));
    assert_eq!("true", &format!("{}", val_true));
    assert_eq!("false", &format!("{}", val_false));
    assert_eq!("9999-12-31T23:59:59.9999999-00:00", &format!("{}", val_datetime));
    assert_eq!("\"foobar1\"", &format!("{}", val_basic_str));
    assert_eq!("'foobar2'", &format!("{}", val_literal_str));
    assert_eq!("\"\"\"foobar3\"\"\"", &format!("{}", val_ml_basic_str));
    assert_eq!("'''foobar4'''", &format!("{}", val_ml_literal_str));
    assert_eq!("[3000, [40000, 50.5], 'barbaz']", &format!("{}", val_array));
    assert_eq!("{foo = true, bar = {baz = false, qux = 2016}, plugh = 3333.444}",
      &format!("{}", val_inline_table));
  }

  #[test]
  fn test_create_int() {
    assert_eq!(Value::Integer("9223372036854775807".into()), Value::int(9223372036854775807));
  }

  #[test]
  fn test_create_int_from_str() {
    assert_eq!(Value::Integer("-9223372036854775808".into()), Value::int_from_str("-9223372036854775808").unwrap());
  }

  #[test]
  fn test_create_int_from_str_fail() {
    assert!(Value::int_from_str("q-9223$37(203)[]M807").is_err());
  }

  #[test]
  fn test_create_float() {
    assert_eq!(Value::Float("179769000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000".into()), Value::float(1.79769e+308));
  }

  #[test]
  fn test_create_float_from_str() {
    assert_eq!(Value::Float("2.22507e-308".into()), Value::float_from_str("2.22507e-308").unwrap());
  }

  #[test]
  fn test_create_float_from_str_fail() {
    assert!(Value::float_from_str("q2.3e++10eipi").is_err());
  }

  #[test]
  fn test_create_bool() {
    assert_eq!(Value::Boolean(false), Value::bool(false));
  }

  #[test]
  fn test_create_bool_from_str() {
    assert_eq!(Value::Boolean(true), Value::bool_from_str("TrUe").unwrap());
  }

  #[test]
  fn test_create_bool_from_str_fail() {
    assert!(Value::bool_from_str("TFraulese").is_err());
  }

  #[test]
  fn test_create_date_from_int() {
    assert_eq!(Value::DateTime(DateTime::new(Date::new_str("2012", "01", "03"), None)),
      Value::date_from_int(2012, 1, 3).unwrap());
  }

  #[test]
  fn test_create_date_from_int_fail() {
    assert!(Value::date_from_int(0, 2, 20).is_err());
    assert!(Value::date_from_int(2016, 0, 20).is_err());
    assert!(Value::date_from_int(2016, 1, 0).is_err());
    assert!(Value::date_from_int(2016, 1, 32).is_err());
    assert!(Value::date_from_int(2016, 4, 31).is_err());
    assert!(Value::date_from_int(2016, 2, 30).is_err());
    assert!(Value::date_from_int(2015, 2, 29).is_err());
    assert!(Value::date_from_int(1900, 2, 29).is_err());
    assert!(Value::date_from_int(2000, 2, 30).is_err());
  }

  #[test]
  fn test_create_date_from_str() {
    assert_eq!(Value::DateTime(DateTime::new(Date::new_str("2012", "01", "03"), None)),
      Value::date_from_str("2012", "01", "03").unwrap());
  }

  #[test]
  fn test_create_date_from_str_fail() {
    assert!(Value::date_from_str("12345", "01", "01").is_err());
    assert!(Value::date_from_str("2016", "012", "01").is_err());
    assert!(Value::date_from_str("2016", "01", "012").is_err());
    assert!(Value::date_from_str("201q", "01", "01").is_err());
    assert!(Value::date_from_str("2016", "0q", "01").is_err());
    assert!(Value::date_from_str("2016", "01", "0q").is_err());
    assert!(Value::date_from_str("201", "01", "01").is_err());
    assert!(Value::date_from_str("2016", "1", "01").is_err());
    assert!(Value::date_from_str("2016", "01", "1").is_err());
  }

  #[test]
  fn test_create_datetime_from_int() {
    assert_eq!(Value::DateTime(DateTime::new(Date::new_str("2012", "01", "03"), Some(Time::new_str(
      "03", "30", "30", None, None
    )))), Value::datetime_from_int(2012, 1, 3, 3, 30, 30).unwrap());
  }

  #[test]
  fn test_create_datetime_from_int_fail() {
    assert!(Value::datetime_from_int(2012, 1, 3, 24, 30, 30).is_err());
    assert!(Value::datetime_from_int(2012, 1, 3, 3, 60, 30).is_err());
    assert!(Value::datetime_from_int(2012, 1, 3, 3, 30, 60).is_err());
  }

  #[test]
  fn test_create_datetime_from_str() {
    assert_eq!(Value::DateTime(DateTime::new(Date::new_str("2012", "01", "03"), Some(Time::new_str(
      "03", "30", "30", None, None
    )))), Value::datetime_from_str("2012", "01", "03", "03", "30", "30").unwrap());
  }

  #[test]
  fn test_create_datetime_from_str_fail() {
    assert!(Value::datetime_from_str("2012", "01", "03", "3", "30", "30").is_err());
    assert!(Value::datetime_from_str("2012", "01", "03", "03", "3", "30").is_err());
    assert!(Value::datetime_from_str("2012", "01", "03", "03", "30", "3").is_err());
    assert!(Value::datetime_from_str("2012", "01", "03", "033", "30", "30").is_err());
    assert!(Value::datetime_from_str("2012", "01", "03", "03", "303", "303").is_err());
    assert!(Value::datetime_from_str("2012", "01", "03", "0q", "30", "30").is_err());
    assert!(Value::datetime_from_str("2012", "01", "03", "03", "3q", "30").is_err());
    assert!(Value::datetime_from_str("2012", "01", "03", "03", "30", "3q").is_err());
  }

  #[test]
  fn test_create_datetime_frac_from_int() {
    assert_eq!(Value::DateTime(DateTime::new(Date::new_str("2012", "01", "03"), Some(Time::new_str(
      "03", "30", "30", Some("3030"), None
    )))), Value::datetime_frac_from_int(2012, 1, 3, 3, 30, 30, 3030).unwrap());
  }

  #[test]
  fn test_create_datetime_frac_from_int_fail() {
    assert!(Value::datetime_frac_from_int(2012, 1, 0, 3, 30, 30, 3030).is_err());
  }

  #[test]
  fn test_create_datetime_frac_from_str() {
    assert_eq!(Value::DateTime(DateTime::new(Date::new_str("2012", "01", "03"), Some(Time::new_str(
      "03", "30", "30", Some("3030"), None
    )))), Value::datetime_frac_from_str("2012", "01", "03", "03", "30", "30", "3030").unwrap());
  }

  #[test]
  fn test_create_datetime_frac_from_str_fail() {
    assert!(Value::datetime_frac_from_str("2012", "01", "03", "03", "30", "30", "q3030").is_err());
  }

  #[test]
  fn test_create_datetime_offset_from_int() {
    assert_eq!(Value::DateTime(DateTime::new(Date::new_str("2012", "01", "03"), Some(Time::new_str(
      "03", "30", "30", None, Some(TimeOffset::Time(TimeOffsetAmount::new_str(
        "+", "07", "45"
      )))
    )))), Value::datetime_offset_from_int(2012, 1, 3, 3, 30, 30, '+', 7, 45).unwrap());
  }

  #[test]
  fn test_create_datetime_offset_from_int_fail() {
    assert!(Value::datetime_offset_from_int(2012, 1, 3, 3, 30, 30, 'q', 7, 45).is_err());
    assert!(Value::datetime_offset_from_int(2012, 1, 3, 3, 30, 30, '+', 24, 45).is_err());
    assert!(Value::datetime_offset_from_int(2012, 1, 3, 3, 30, 30, '+', 7, 60).is_err());
  }

  #[test]
  fn test_create_datetime_offset_from_str() {
    assert_eq!(Value::DateTime(DateTime::new(Date::new_str("2012", "01", "03"), Some(Time::new_str(
      "03", "30", "30", None, Some(TimeOffset::Time(TimeOffsetAmount::new_str(
        "+", "07", "45"
      )))
    )))), Value::datetime_offset_from_str("2012", "01", "03", "03", "30", "30", "+", "07", "45").unwrap());
  }

  #[test]
  fn test_create_datetime_offset_from_str_fail() {
    assert!(Value::datetime_offset_from_str("2012", "01", "03", "03", "30", "30", "+", "077", "45").is_err());
    assert!(Value::datetime_offset_from_str("2012", "01", "03", "03", "30", "30", "+", "07", "455").is_err());
    assert!(Value::datetime_offset_from_str("2012", "01", "03", "03", "30", "30", "+", "7", "45").is_err());
    assert!(Value::datetime_offset_from_str("2012", "01", "03", "03", "30", "30", "+", "07", "5").is_err());
    assert!(Value::datetime_offset_from_str("2012", "01", "03", "03", "30", "30", "q", "07", "45").is_err());
  }

  #[test]
  fn test_create_datetime_zulu_from_int() {
    assert_eq!(Value::DateTime(DateTime::new(Date::new_str("2012", "01", "03"), Some(Time::new_str(
      "03", "30", "30", None, Some(TimeOffset::Zulu)
    )))), Value::datetime_zulu_from_int(2012, 1, 3, 3, 30, 30).unwrap());
  }

  #[test]
  fn test_create_datetime_zulu_from_int_fail() {
    assert!(Value::datetime_zulu_from_int(2012, 1, 0, 3, 30, 30).is_err());
  }

  #[test]
  fn test_create_datetime_zulu_from_str() {
    assert_eq!(Value::DateTime(DateTime::new(Date::new_str("2012", "01", "03"), Some(Time::new_str(
      "03", "30", "30", None, Some(TimeOffset::Zulu)
    )))), Value::datetime_zulu_from_str("2012", "01", "03", "03", "30", "30").unwrap());
  }

  #[test]
  fn test_create_datetime_zulu_from_str_fail() {
    assert!(Value::datetime_zulu_from_str("q2012", "01", "03", "03", "30", "30").is_err());
  }

  #[test]
  fn test_create_datetime_full_zulu_from_int() {
    assert_eq!(Value::DateTime(DateTime::new(Date::new_str("2012", "01", "03"), Some(Time::new_str(
      "03", "30", "30", Some("3030"), Some(TimeOffset::Zulu)
    )))), Value::datetime_full_zulu_from_int(2012, 1, 3, 3, 30, 30, 3030).unwrap());
  }

  #[test]
  fn test_create_datetime_full_zulu_from_int_fail() {
    assert!(Value::datetime_full_zulu_from_int(2012, 1, 0, 3, 30, 30, 3030).is_err());
  }

  #[test]
  fn test_create_datetime_full_zulu_from_str() {
    assert_eq!(Value::DateTime(DateTime::new(Date::new_str("2012", "01", "03"), Some(Time::new_str(
      "03", "30", "30", Some("3030"), Some(TimeOffset::Zulu)
    )))), Value::datetime_full_zulu_from_str("2012", "01", "03", "03", "30", "30", "3030").unwrap());
  }

  #[test]
  fn test_create_datetime_full_zulu_from_str_fail() {
    assert!(Value::datetime_full_zulu_from_str("q2012", "01", "03", "03", "30", "30", "3030").is_err());
  }

  #[test]
  fn test_create_datetime_full_from_int() {
    assert_eq!(Value::DateTime(DateTime::new(Date::new_str("2012", "01", "03"), Some(Time::new_str(
      "03", "30", "30", Some("3030"), Some(TimeOffset::Time(TimeOffsetAmount::new_str(
        "+", "07", "45"
      )))
    )))), Value::datetime_full_from_int(2012, 1, 3, 3, 30, 30, 3030, '+', 7, 45).unwrap());
  }

  #[test]
  fn test_create_datetime_full_from_int_fail() {
    assert!(Value::datetime_full_from_int(2012, 1, 0, 3, 30, 30, 3030, '+', 7, 45).is_err());
    assert!(Value::datetime_full_from_int(2012, 13, 0, 3, 30, 30, 3030, '+', 7, 45).is_err());
    assert!(Value::datetime_full_from_int(2012, 1, 0, 3, 61, 30, 3030, '+', 7, 45).is_err());
    assert!(Value::datetime_full_from_int(2012, 1, 0, 3, 30, 30, 3030, '+', 25, 45).is_err());
    assert!(Value::datetime_full_from_int(2012, 1, 0, 3, 30, 30, 3030, 'q', 7, 45).is_err());
  }

  #[test]
  fn test_create_datetime_full_from_str() {
    assert_eq!(Value::DateTime(DateTime::new(Date::new_str("2012", "01", "03"), Some(Time::new_str(
      "03", "30", "30", Some("3030"), Some(TimeOffset::Time(TimeOffsetAmount::new_str(
        "+", "07", "45"
      )))
    )))), Value::datetime_full_from_str("2012", "01", "03", "03", "30", "30", "3030", "+", "07", "45").unwrap());
  }

  #[test]
  fn test_create_datetime_full_from_str_fail() {
    assert!(Value::datetime_full_from_str("2012", "01", "03", "03", "30", "30", "q3030", "+", "07", "45").is_err());
    assert!(Value::datetime_full_from_str("2012", "01", "03", "03", "30", "30", "3030", "q", "07", "45").is_err());
  }

  #[test]
  fn test_datetime_parse() {
    assert_eq!(Value::DateTime(DateTime::new(Date::new_str("2012", "01", "03"), Some(Time::new_str(
      "03", "30", "30", Some("3030"), Some(TimeOffset::Time(TimeOffsetAmount::new_str(
        "+", "07", "45"
      )))
    )))), Value::datetime_parse("2012-01-03T03:30:30.3030+07:45").unwrap());

    assert_eq!(Value::DateTime(DateTime::new(Date::new_str("2012", "01", "03"), Some(Time::new_str(
      "03", "30", "30", Some("3030"), Some(TimeOffset::Zulu)
    )))), Value::datetime_parse("2012-01-03T03:30:30.3030Z").unwrap());

    assert_eq!(Value::DateTime(DateTime::new(Date::new_str("2012", "01", "03"), Some(Time::new_str(
      "03", "30", "30", None, Some(TimeOffset::Zulu)
    )))), Value::datetime_parse("2012-01-03T03:30:30Z").unwrap());

    assert_eq!(Value::DateTime(DateTime::new(Date::new_str("2012", "01", "03"), Some(Time::new_str(
      "03", "30", "30", None, Some(TimeOffset::Time(TimeOffsetAmount::new_str(
        "+", "07", "45"
      )))
    )))), Value::datetime_parse("2012-01-03T03:30:30+07:45").unwrap());

    assert_eq!(Value::DateTime(DateTime::new(Date::new_str("2012", "01", "03"), Some(Time::new_str(
      "03", "30", "30", None, None
    )))), Value::datetime_parse("2012-01-03T03:30:30").unwrap());

    assert_eq!(Value::DateTime(DateTime::new(Date::new_str("2012", "01", "03"), None
    )), Value::datetime_parse("2012-01-03").unwrap());
  }

  #[test]
  fn test_datetime_parse_fail() {
    assert!(Value::datetime_parse("012-01-03T03:30:30.3030+07:45").is_err());
    assert!(Value::datetime_parse("2012-1-03T03:30:30.3030+07:45").is_err());
    assert!(Value::datetime_parse("2012-01-3T03:30:30.3030+07:45").is_err());
    assert!(Value::datetime_parse("2012-01-03T3:30:30.3030+07:45").is_err());
    assert!(Value::datetime_parse("2012-01-03T03:0:30.3030+07:45").is_err());
    assert!(Value::datetime_parse("2012-01-03T03:30:0.3030+07:45").is_err());
    assert!(Value::datetime_parse("2012-01-03T03:30:30.+07:45").is_err());
    assert!(Value::datetime_parse("2012-01-03T03:30:30.303007:45").is_err());
    assert!(Value::datetime_parse("2012-01-03T03:30:30.3030+7:45").is_err());
    assert!(Value::datetime_parse("2012-01-03T03:30:30.3030+07:5").is_err());
    assert!(Value::datetime_parse("20123-01-03T03:30:30.3030+07:45").is_err());
    assert!(Value::datetime_parse("2012-013-03T03:30:30.3030+07:45").is_err());
    assert!(Value::datetime_parse("2012-01-033T03:30:30.3030+07:45").is_err());
    assert!(Value::datetime_parse("2012-01-03T033:30:30.3030+07:45").is_err());
    assert!(Value::datetime_parse("2012-01-03T03:303:30.3030+07:45").is_err());
    assert!(Value::datetime_parse("2012-01-03T03:30:303.3030+07:45").is_err());
    assert!(Value::datetime_parse("2012-01-03T03:30:30.3030+073:45").is_err());
    assert!(Value::datetime_parse("2012-01-03T03:30:30.3030+07:453").is_err());
    assert!(Value::datetime_parse("2012q01-03T03:30:30.3030+07:45").is_err());
    assert!(Value::datetime_parse("2012-01q03T03:30:30.3030+07:45").is_err());
    assert!(Value::datetime_parse("2012-01-03q03:30:30.3030+07:45").is_err());
    assert!(Value::datetime_parse("2012-01-03T03q30:30.3030+07:45").is_err());
    assert!(Value::datetime_parse("2012-01-03T03:30q30.3030+07:45").is_err());
    assert!(Value::datetime_parse("2012-01-03T03:30:30q3030+07:45").is_err());
    assert!(Value::datetime_parse("2012-01-03T03:30:30.3030q07:45").is_err());
    assert!(Value::datetime_parse("2012-01-03T03:30:30.3030+07q45").is_err());
  }

  #[test]
  fn test_create_basic_string() {
    assert_eq!(Value::String("foobar".into(), StrType::Basic), Value::basic_string("foobar").unwrap());
  }

  #[test]
  fn test_create_basic_string_fail() {
    assert!(Value::basic_string("foo\nbar").is_err());
  }

  #[test]
  fn test_create_ml_basic_string() {
    assert_eq!(Value::String("foobar".into(), StrType::MLBasic), Value::ml_basic_string("foobar").unwrap());
  }

  #[test]
  fn test_create_ml_basic_string_fail() {
    assert!(Value::ml_basic_string(r#"foo\qbar"#).is_err());
  }

  #[test]
  fn test_create_literal_string() {
    assert_eq!(Value::String("foobar".into(), StrType::Literal), Value::literal_string("foobar").unwrap());
  }

  #[test]
  fn test_create_literal_string_fail() {
    assert!(Value::literal_string(r#"foo
bar"#).is_err());
  }

  #[test]
  fn test_create_ml_literal_string() {
    assert_eq!(Value::String("foobar".into(), StrType::MLLiteral), Value::ml_literal_string("foobar").unwrap());
  }

  #[test]
  fn test_create_ml_literal_string_fail() {
    // This string contains an invisible 0xC char between foo and bar. It's visible in
    // Sublime Text, but not in VS Code
    assert!(Value::ml_literal_string("foobar").is_err());
  }

}