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//! # 🕗 Timelang
//!
//! [![Crates.io](https://img.shields.io/crates/v/timelang)](https://crates.io/crates/timelang)
//! [![docs.rs](https://img.shields.io/docsrs/timelang?label=docs)](https://docs.rs/timelang/latest/timelang/)
//! [![Build Status](https://img.shields.io/github/actions/workflow/status/sam0x17/timelang/ci.yaml)](https://github.com/sam0x17/timelang/actions/workflows/ci.yaml?query=branch%3Amain)
//! [![MIT License](https://img.shields.io/github/license/sam0x17/timelang)](https://github.com/sam0x17/timelang/blob/main/LICENSE)
//!
//! Timelang is a simple DSL (Domain Specific Language) for representing human-readable
//! time-related expressions including specific date/times, relative expressions like "3 hours
//! from now", time ranges, and durations.
//!
//!
//! ## Getting Started
//!
//! To use timelang, you should take a look at [TimeExpression], which is the top-level entry
//! point of the AST, or some of the more specific types like [Duration], [PointInTime],
//! and [TimeRange].
//!
//! All nodes in timelang impl [FromStr] as well as [syn::parse::Parse] which is used for the
//! internal parsing logic. The standard [Display] impl is used on all node types as the
//! preferred means of outputting them to a string.
//!
//! Note that for the moment, only years, months, weeks, days, hours, and minutes are supported
//! in timelang, but seconds and more might be added later. Generally better than minute
//! resolution is not needed in many of the common use-cases for timelang.
//!
//!
//! ## Examples
//!
//! The following are all examples of valid expressions in timelang:
//! - `now` ([RelativeTime])
//! - `tomorrow` ([RelativeTime])
//! - `next tuesday` ([RelativeTime])
//! - `day after tomorrow` ([RelativeTime])
//! - `the day before yesterday` ([RelativeTime])
//! - `20/4/2021` ([Date])
//! - `11:21 AM` ([Time])
//! - `15/6/2022 at 3:58 PM` ([DateTime] / [PointInTime::Absolute])
//! - `2 hours, 37 minutes` ([Duration])
//! - `5 years, 2 months, 3 weeks and 11 minutes` ([Duration])
//! - `7 days ago` ([RelativeTime])
//! - `2 years and 10 minutes from now` ([RelativeTime])
//! - `5 days, 3 weeks, 6 minutes after 15/4/2025 at 9:27 AM` ([RelativeTime])
//! - `from 1/1/2023 at 14:07 to 15/1/2023` ([TimeRange])
//! - `from 19/3/2024 at 10:07 AM to 3 months 2 days after 3/9/2027 at 5:27 PM` ([TimeRange])
//! - `2 days and 14 hours after the day after tomorrow` ([RelativeTime])
//!
//!
//! ## Context Free Grammar
//! Here is a rough CFG (Context Free Grammar) for timelang:
//!
//! ```cfg
//! S → TimeExpression
//! TimeExpression → PointInTime | TimeRange | Duration
//! PointInTime → AbsoluteTime | RelativeTime
//! TimeRange → 'from' PointInTime 'to' PointInTime
//! Duration → Number TimeUnit ((','? 'and')? Number TimeUnit)*
//! AbsoluteTime → Date | DateTime
//! RelativeTime → Duration TimeDirection | NamedRelativeTime | 'next' RelativeTimeUnit | 'last' RelativeTimeUnit
//! NamedRelativeTime → 'now' | 'today' | 'tomorrow' | 'yesterday' | 'day after tomorrow' | 'the day after tomorrow' | 'day before yesterday' | 'the day before yesterday'
//! Date → DayOfMonth '/' Month '/' Year
//! DateTime → Date ('at')? Time
//! Time → Hour ':' Minute AmPm?
//! Hour → Number
//! Minute → Number
//! Month → Number
//! DayOfMonth → Number
//! Year → Number
//! AmPm → 'AM' | 'PM'
//! TimeUnit → 'minutes' | 'hours' | 'days' | 'weeks' | 'months' | 'years'
//! TimeDirection → 'after' AbsoluteTime | 'before' AbsoluteTime | 'after' NamedRelativeTime | 'before' NamedRelativeTime | 'before' 'next' RelativeTimeUnit | 'before' 'last' RelativeTimeUnit | 'after' 'next' RelativeTimeUnit | 'after' 'last' RelativeTimeUnit | 'ago' | 'from now'
//! RelativeTimeUnit → 'week' | 'month' | 'year' | 'monday' | 'tuesday' | 'wednesday' | 'thursday' | 'friday' | 'saturday' | 'sunday'
//! Number → [Any positive integer value]
//! ```
//!
//! It is worth noting that this CFG is slightly more permissive than the actual timelang
//! grammar, particularly when it comes to validating the permitted number ranges for various
//! times.
//!
//! ## Notes
//!
//! * At the moment [syn](https://crates.io/crates/syn) is used for parsing. This will likely be
//! swapped out for a TBD parsing crate, but it was easy to quickly get this off the ground using
//! syn. Whatever new crate we use will hopefully allow us to make timelang compatible with no
//! std.
//! * Timelang is unambiguous, meaning there is exactly one tree representation for all possible
//! timelang sentences. If you can come up with an ambiguous sentence, please let us know by
//! submitting a GitHub issue!
#![deny(missing_docs)]
use std::{
fmt::Display,
ops::{Add, Div, Mul, Sub},
str::FromStr,
};
use syn::{
parse::{Parse, ParseStream, Result},
Error, Ident, LitInt, Token,
};
#[cfg(test)]
mod tests;
/// The top-level entry-point for the timelang AST.
///
/// Typically you will want to use a more specific type like [Duration], [PointInTime], or
/// [TimeRange], but this top-level node-type is provided so that we can consider timelang to
/// be a distinct language.
///
/// Note that [TimeExpression] is [Sized], and thus all expressions in timelang have a
/// predictable memory size and do not require any heap allocations. That said, _parsing_
/// expressions in timelang does require some temporary allocations that go away when parsing
/// is complete.
///
/// ## Examples
///
/// Specific Date:
/// ```
/// use timelang::*;
/// assert_eq!(
/// "20/4/2021".parse::<TimeExpression>().unwrap(),
/// TimeExpression::Specific(PointInTime::Absolute(AbsoluteTime::Date(Date(
/// Month::April,
/// DayOfMonth(20),
/// Year(2021)
/// ))))
/// );
/// ```
///
/// Specific DateTime:
/// ```
/// use timelang::*;
/// assert_eq!(
/// "15/6/2022 at 14:00".parse::<AbsoluteTime>().unwrap(),
/// AbsoluteTime::DateTime(DateTime(
/// Date(Month::June, DayOfMonth(15), Year(2022)),
/// Time(Hour::Hour24(14), Minute(0))
/// ))
/// );
/// ```
///
/// Time Range:
/// ```
/// use timelang::*;
/// assert_eq!(
/// "from 1/1/2023 to 15/1/2023"
/// .parse::<TimeExpression>()
/// .unwrap(),
/// TimeExpression::Range(TimeRange(
/// PointInTime::Absolute(AbsoluteTime::Date(Date(
/// Month::January,
/// DayOfMonth(1),
/// Year(2023)
/// ))),
/// PointInTime::Absolute(AbsoluteTime::Date(Date(
/// Month::January,
/// DayOfMonth(15),
/// Year(2023)
/// )))
/// ))
/// );
/// ```
///
/// Duration (multiple units with comma):
/// ```
/// use timelang::*;
/// assert_eq!(
/// "2 hours, 30 minutes".parse::<TimeExpression>().unwrap(),
/// TimeExpression::Duration(Duration {
/// hours: Number(2),
/// minutes: Number(30),
/// days: Number(0),
/// weeks: Number(0),
/// months: Number(0),
/// years: Number(0)
/// })
/// );
/// ```
///
/// Duration (multiple units with `and`):
/// ```
/// use timelang::*;
/// assert_eq!(
/// "1 year and 6 months".parse::<TimeExpression>().unwrap(),
/// TimeExpression::Duration(Duration {
/// years: Number(1),
/// months: Number(6),
/// days: Number(0),
/// weeks: Number(0),
/// hours: Number(0),
/// minutes: Number(0)
/// })
/// );
/// ```
///
/// Relative Time (using `ago`):
/// ```
/// use timelang::*;
/// assert_eq!(
/// "3 days ago".parse::<TimeExpression>().unwrap(),
/// TimeExpression::Specific(PointInTime::Relative(RelativeTime::Directional {
/// duration: Duration {
/// days: Number(3),
/// minutes: Number(0),
/// hours: Number(0),
/// weeks: Number(0),
/// months: Number(0),
/// years: Number(0)
/// },
/// dir: TimeDirection::Ago
/// }))
/// );
/// ```
///
/// Relative Time (using `from now`):
/// ```
/// use timelang::*;
/// assert_eq!(
/// "5 days, 10 hours, and 35 minutes from now"
/// .parse::<TimeExpression>()
/// .unwrap(),
/// TimeExpression::Specific(PointInTime::Relative(RelativeTime::Directional {
/// duration: Duration {
/// minutes: Number(35),
/// hours: Number(10),
/// days: Number(5),
/// weeks: Number(0),
/// months: Number(0),
/// years: Number(0)
/// },
/// dir: TimeDirection::FromNow
/// }))
/// );
/// ```
///
/// Relative Time (`after` a specific date):
/// ```
/// use timelang::*;
/// assert_eq!(
/// "2 hours, 3 minutes after 10/10/2022"
/// .parse::<TimeExpression>()
/// .unwrap(),
/// TimeExpression::Specific(PointInTime::Relative(RelativeTime::Directional {
/// duration: Duration {
/// hours: Number(2),
/// minutes: Number(3),
/// days: Number(0),
/// weeks: Number(0),
/// months: Number(0),
/// years: Number(0)
/// },
/// dir: TimeDirection::AfterAbsolute(AbsoluteTime::Date(Date(
/// Month::October,
/// DayOfMonth(10),
/// Year(2022)
/// )))
/// }))
/// );
/// ```
///
/// Relative Time (`before` a specific date/time):
/// ```
/// use timelang::*;
/// assert_eq!(
/// "1 day before 31/12/2023 at 11:13 PM"
/// .parse::<TimeExpression>()
/// .unwrap(),
/// TimeExpression::Specific(PointInTime::Relative(RelativeTime::Directional {
/// duration: Duration {
/// days: Number(1),
/// minutes: Number(0),
/// hours: Number(0),
/// weeks: Number(0),
/// months: Number(0),
/// years: Number(0)
/// },
/// dir: TimeDirection::BeforeAbsolute(AbsoluteTime::DateTime(DateTime(
/// Date(Month::December, DayOfMonth(31), Year(2023)),
/// Time(Hour::Hour12(11, AmPm::PM), Minute(13))
/// )))
/// }))
/// );
/// ```
///
/// Time Range (with specific date/times):
/// ```
/// use timelang::*;
/// assert_eq!(
/// "from 1/1/2024 at 10:00 to 2/1/2024 at 15:30"
/// .parse::<TimeExpression>()
/// .unwrap(),
/// TimeExpression::Range(TimeRange(
/// PointInTime::Absolute(AbsoluteTime::DateTime(DateTime(
/// Date(Month::January, DayOfMonth(1), Year(2024)),
/// Time(Hour::Hour24(10), Minute(0))
/// ))),
/// PointInTime::Absolute(AbsoluteTime::DateTime(DateTime(
/// Date(Month::January, DayOfMonth(2), Year(2024)),
/// Time(Hour::Hour24(15), Minute(30))
/// )))
/// ))
/// );
/// ```
///
/// Relative Time (Named):
/// ```
/// use timelang::*;
/// assert_eq!("now".parse::<RelativeTime>().unwrap(), RelativeTime::Named(NamedRelativeTime::Now));
/// assert_eq!(
/// "tomorrow".parse::<RelativeTime>().unwrap(),
/// RelativeTime::Named(NamedRelativeTime::Tomorrow)
/// );
/// assert_eq!(
/// "yesterday".parse::<RelativeTime>().unwrap(),
/// RelativeTime::Named(NamedRelativeTime::Yesterday)
/// );
/// assert_eq!(
/// "day before yesterday".parse::<RelativeTime>().unwrap(),
/// RelativeTime::Named(NamedRelativeTime::DayBeforeYesterday)
/// );
/// // note the optional `the`
/// assert_eq!(
/// "the day after tomorrow".parse::<RelativeTime>().unwrap(),
/// RelativeTime::Named(NamedRelativeTime::DayAfterTomorrow)
/// );
/// assert_eq!(
/// "next tuesday".parse::<RelativeTime>().unwrap(),
/// RelativeTime::Next(RelativeTimeUnit::Tuesday)
/// );
/// assert_eq!(
/// "last wednesday".parse::<RelativeTime>().unwrap(),
/// RelativeTime::Last(RelativeTimeUnit::Wednesday)
/// );
/// assert_eq!(
/// "3 days before yesterday".parse::<RelativeTime>().unwrap(),
/// RelativeTime::Directional {
/// duration: Duration {
/// minutes: Number(0),
/// hours: Number(0),
/// days: Number(3),
/// weeks: Number(0),
/// months: Number(0),
/// years: Number(0)
/// },
/// dir: TimeDirection::BeforeNamed(NamedRelativeTime::Yesterday)
/// }
/// );
/// assert_eq!(
/// "2 days and 14 hours after the day after tomorrow".parse::<RelativeTime>().unwrap(),
/// RelativeTime::Directional {
/// duration: Duration {
/// minutes: Number(0),
/// hours: Number(14),
/// days: Number(2),
/// weeks: Number(0),
/// months: Number(0),
/// years: Number(0)
/// },
/// dir: TimeDirection::AfterNamed(NamedRelativeTime::DayAfterTomorrow)
/// }
/// );
/// assert_eq!(
/// "2 weeks before last sunday".parse::<RelativeTime>().unwrap(),
/// RelativeTime::Directional {
/// duration: Duration {
/// minutes: Number(0),
/// hours: Number(0),
/// days: Number(0),
/// weeks: Number(2),
/// months: Number(0),
/// years: Number(0)
/// },
/// dir: TimeDirection::BeforeLast(RelativeTimeUnit::Sunday)
/// }
/// );
/// assert_eq!(
/// "3 years, 2 weeks after next thursday".parse::<RelativeTime>().unwrap(),
/// RelativeTime::Directional {
/// duration: Duration {
/// minutes: Number(0),
/// hours: Number(0),
/// days: Number(0),
/// weeks: Number(2),
/// months: Number(0),
/// years: Number(3)
/// },
/// dir: TimeDirection::AfterNext(RelativeTimeUnit::Thursday)
/// }
/// );
/// ```
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
pub enum TimeExpression {
/// Represents a [PointInTime] expression.
Specific(PointInTime), // (LitInt, Ident) or (LitInt, Token![/])
/// Represents a [TimeRange] expression.
Range(TimeRange), // Ident, LitInt
/// Represents a [Duration] expression.
Duration(Duration), // LitInt, Ident
}
impl Parse for TimeExpression {
fn parse(input: ParseStream) -> Result<Self> {
if !input.peek(Ident) && !input.peek(LitInt) {
return Err(Error::new(input.span(), "expected [number] or [keyword]"));
}
if input.peek(Ident) {
let ident = input.fork().parse::<Ident>()?;
if ident.to_string().to_lowercase().as_str() == "from" {
return Ok(TimeExpression::Range(input.parse()?));
}
return Ok(TimeExpression::Specific(input.parse()?));
}
if input.peek(LitInt) && input.peek2(Token![/]) {
// case 2 for PointInTime
return Ok(TimeExpression::Specific(input.parse()?));
}
// now we either have a Duration or PointInTime starting with a Duration
let fork = input.fork();
if fork.parse::<PointInTime>().is_ok() {
return Ok(TimeExpression::Specific(input.parse()?));
}
Ok(TimeExpression::Duration(input.parse()?))
}
}
impl Display for TimeExpression {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self {
TimeExpression::Specific(point) => write!(f, "{point}"),
TimeExpression::Range(tr) => write!(f, "{tr}"),
TimeExpression::Duration(dur) => write!(f, "{dur}"),
}
}
}
/// Represents a range of two valid [PointInTime]s that together define the start and end of
/// some defined period of time.
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
pub struct TimeRange(pub PointInTime, pub PointInTime);
impl Parse for TimeRange {
fn parse(input: ParseStream) -> Result<Self> {
let ident = input.parse::<Ident>()?;
if ident.to_string().to_lowercase() != "from" {
return Err(Error::new(ident.span(), "expected `from`"));
}
let t1 = input.parse::<PointInTime>()?;
let ident = input.parse::<Ident>()?;
if ident.to_string().to_lowercase() != "to" {
return Err(Error::new(ident.span(), "expected `to`"));
}
let t2 = input.parse::<PointInTime>()?;
Ok(TimeRange(t1, t2))
}
}
impl Display for TimeRange {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
write!(f, "from {} to {}", self.0, self.1)
}
}
/// Represents a specific duration of time that is not anchored at any particular point in time.
///
/// Note that individual components, if not specified, will be recorded as `0`. Such components
/// will not appear when the [Duration] is rendered, printed, or displayed.
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
pub struct Duration {
/// The number of minutes.
pub minutes: Number,
/// The number of hours.
pub hours: Number,
/// The number of days.
pub days: Number,
/// The number of weeks.
pub weeks: Number,
/// The number of months.
pub months: Number,
/// The number of years.
pub years: Number,
}
impl Parse for Duration {
fn parse(input: ParseStream) -> Result<Self> {
let mut minutes: Option<Number> = None;
let mut hours: Option<Number> = None;
let mut days: Option<Number> = None;
let mut weeks: Option<Number> = None;
let mut months: Option<Number> = None;
let mut years: Option<Number> = None;
while input.peek(LitInt) {
let num = input.parse::<Number>()?;
let unit = input.parse::<TimeUnit>()?;
match unit {
TimeUnit::Minutes => minutes = Some(minutes.unwrap_or(Number(0)) + num),
TimeUnit::Hours => hours = Some(hours.unwrap_or(Number(0)) + num),
TimeUnit::Days => days = Some(days.unwrap_or(Number(0)) + num),
TimeUnit::Weeks => weeks = Some(weeks.unwrap_or(Number(0)) + num),
TimeUnit::Months => months = Some(months.unwrap_or(Number(0)) + num),
TimeUnit::Years => years = Some(years.unwrap_or(Number(0)) + num),
}
if input.peek(Token![,]) {
input.parse::<Token![,]>()?;
}
if input.peek(Ident) {
let ident = input.fork().parse::<Ident>()?; // don't consume if it isn't `and`
if ident.to_string().to_lowercase() == "and" {
input.parse::<Ident>()?; // consume the `and`
}
}
}
if minutes.is_none()
&& hours.is_none()
&& days.is_none()
&& weeks.is_none()
&& months.is_none()
&& years.is_none()
{
return Err(Error::new(
input.span(),
"expected [number] followed by one of `minutes`, `hours`, `days`, `years`",
));
}
Ok(Duration {
minutes: minutes.unwrap_or(Number(0)),
hours: hours.unwrap_or(Number(0)),
days: days.unwrap_or(Number(0)),
weeks: weeks.unwrap_or(Number(0)),
months: months.unwrap_or(Number(0)),
years: years.unwrap_or(Number(0)),
})
}
}
impl Display for Duration {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
let mut before = false;
if self.years > 0 {
before = true;
}
if self.years == 1 {
write!(f, "1 year")?;
} else if self.years > 1 {
write!(f, "{} years", self.years)?;
}
if self.months > 0 {
if before {
write!(f, ", ")?;
}
before = true;
}
if self.months == 1 {
write!(f, "1 month")?;
} else if self.months > 1 {
write!(f, "{} months", self.months)?;
}
if self.weeks > 0 {
if before {
write!(f, ", ")?;
}
before = true;
}
if self.weeks == 1 {
write!(f, "1 week")?;
} else if self.weeks > 1 {
write!(f, "{} weeks", self.weeks)?;
}
if self.days > 0 {
if before {
write!(f, ", ")?;
}
before = true;
}
if self.days == 1 {
write!(f, "1 day")?;
} else if self.days > 1 {
write!(f, "{} days", self.days)?;
}
if self.hours > 0 {
if before {
write!(f, ", ")?;
}
before = true;
}
if self.hours == 1 {
write!(f, "1 hour")?;
} else if self.hours > 1 {
write!(f, "{} hours", self.hours)?;
}
if self.minutes > 0 {
if before {
write!(f, ", ")?;
}
}
if self.minutes == 1 {
write!(f, "1 minute")?;
} else if self.minutes > 1 {
write!(f, "{} minutes", self.minutes)?;
}
Ok(())
}
}
/// Represents a specific point in time, which could either be an [AbsoluteTime] (corresponding
/// with a particular [Date] or [DateTime]), or a [RelativeTime] (corresponding with an offset
/// from some [AbsoluteTime] or "now").
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
pub enum PointInTime {
/// Based on a specific [Date] or [DateTime] (fixed point) that involves no relative
/// indirection, like "3 days after 18/3/2024".
Absolute(AbsoluteTime),
/// Based on an offset from some known fixed point in time, like "next tuesday".
Relative(RelativeTime),
}
impl Parse for PointInTime {
fn parse(input: ParseStream) -> Result<Self> {
if input.peek(LitInt) && input.peek2(Token![/]) {
Ok(PointInTime::Absolute(input.parse::<AbsoluteTime>()?))
} else {
Ok(PointInTime::Relative(input.parse::<RelativeTime>()?))
}
}
}
impl Display for PointInTime {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self {
PointInTime::Absolute(abs) => write!(f, "{abs}"),
PointInTime::Relative(rel) => write!(f, "{rel}"),
}
}
}
/// Represents an absolute/fixed point in time, such as a [Date] or [DateTime].
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
pub enum AbsoluteTime {
/// A [Date], such as "23/9/2028".
Date(Date),
/// A [DateTime], such as "28/1/2025 at 5:23 PM" or "1/1/2019 20:15".
DateTime(DateTime),
}
impl Parse for AbsoluteTime {
fn parse(input: ParseStream) -> Result<Self> {
let fork = input.fork();
fork.parse::<Date>()?;
if (fork.peek(LitInt) && fork.peek2(Token![:]) && fork.peek3(LitInt))
|| (fork.peek(Ident) && fork.peek2(LitInt) && fork.peek3(Token![:]))
{
return Ok(AbsoluteTime::DateTime(input.parse()?));
}
Ok(AbsoluteTime::Date(input.parse()?))
}
}
impl Display for AbsoluteTime {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self {
AbsoluteTime::Date(date) => write!(f, "{}", date),
AbsoluteTime::DateTime(date_time) => write!(f, "{}", date_time),
}
}
}
/// Combined with "next" or "after" to denote specific [RelativeTime]s.
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
pub enum RelativeTimeUnit {
/// Week
Week,
/// Month
Month,
/// Year
Year,
/// Monday
Monday,
/// Tuesday
Tuesday,
/// Wednesday
Wednesday,
/// Thursday
Thursday,
/// Friday
Friday,
/// Saturday
Saturday,
/// Sunday
Sunday,
}
impl Parse for RelativeTimeUnit {
fn parse(input: ParseStream) -> Result<Self> {
let ident = input.parse::<Ident>()?;
match ident.to_string().to_lowercase().as_str() {
"week" => Ok(RelativeTimeUnit::Week),
"month" => Ok(RelativeTimeUnit::Month),
"year" => Ok(RelativeTimeUnit::Year),
"monday" => Ok(RelativeTimeUnit::Monday),
"tuesday" => Ok(RelativeTimeUnit::Tuesday),
"wednesday" => Ok(RelativeTimeUnit::Wednesday),
"thursday" => Ok(RelativeTimeUnit::Thursday),
"friday" => Ok(RelativeTimeUnit::Friday),
"saturday" => Ok(RelativeTimeUnit::Saturday),
"sunday" => Ok(RelativeTimeUnit::Sunday),
_ => Err(Error::new(
ident.span(),
"expected one of `week`, `month`, `year`, `monday`, `tuesday`, `wednesday`, \
`thursday`, `friday`, `saturday` or `sunday`",
)),
}
}
}
impl Display for RelativeTimeUnit {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self {
RelativeTimeUnit::Week => f.write_str("week"),
RelativeTimeUnit::Month => f.write_str("month"),
RelativeTimeUnit::Year => f.write_str("year"),
RelativeTimeUnit::Monday => f.write_str("Monday"),
RelativeTimeUnit::Tuesday => f.write_str("Tuesday"),
RelativeTimeUnit::Wednesday => f.write_str("Wednesday"),
RelativeTimeUnit::Thursday => f.write_str("Thursday"),
RelativeTimeUnit::Friday => f.write_str("Friday"),
RelativeTimeUnit::Saturday => f.write_str("Saturday"),
RelativeTimeUnit::Sunday => f.write_str("Sunday"),
}
}
}
/// Corresponds with a named relative time, such as "now", "today", "tomorrow", etc.
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
pub enum NamedRelativeTime {
/// Now
Now,
/// Today
Today,
/// Tomorrow
Tomorrow,
/// Yesterday
Yesterday,
/// The day after tomorrow
DayAfterTomorrow,
/// The day before yesterday
DayBeforeYesterday,
}
impl Parse for NamedRelativeTime {
fn parse(input: ParseStream) -> Result<Self> {
let mut ident1 = input.parse::<Ident>()?;
if let Some(variant) = match ident1.to_string().to_lowercase().as_str() {
"now" => Some(NamedRelativeTime::Now),
"today" => Some(NamedRelativeTime::Today),
"tomorrow" => Some(NamedRelativeTime::Tomorrow),
"yesterday" => Some(NamedRelativeTime::Yesterday),
_ => None,
} {
// single-ident variants
return Ok(variant);
}
if ident1 == "the" && input.peek(Ident) {
// optional "the"
ident1 = input.parse::<Ident>()?;
}
let ident2 = input.parse::<Ident>()?;
let ident3 = input.parse::<Ident>()?;
let ident1_str = ident1.to_string().to_lowercase();
let ident2_str = ident2.to_string().to_lowercase();
let ident3_str = ident3.to_string().to_lowercase();
match (
ident1_str.as_str(),
ident2_str.as_str(),
ident3_str.as_str(),
) {
("day", "after", "tomorrow") => Ok(NamedRelativeTime::DayAfterTomorrow),
("day", "before", "yesterday") => Ok(NamedRelativeTime::DayBeforeYesterday),
_ => {
if ident1_str != "day" {
return Err(Error::new(
ident1.span(),
"expected one of `day`, `now`, `today`, `tomorrow`, `yesterday`, `the`",
));
}
if ident2_str != "before" && ident2_str != "after" {
return Err(Error::new(ident2.span(), "expected `before` or `after`"));
}
if ident3_str == "tomorrow" {
Err(Error::new(ident3.span(), "expected `yesterday`"))
} else {
Err(Error::new(ident3.span(), "expected `tomorrow`"))
}
}
}
}
}
impl Display for NamedRelativeTime {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self {
NamedRelativeTime::Now => f.write_str("now"),
NamedRelativeTime::Today => f.write_str("today"),
NamedRelativeTime::Tomorrow => f.write_str("tomorrow"),
NamedRelativeTime::Yesterday => f.write_str("yesterday"),
NamedRelativeTime::DayAfterTomorrow => f.write_str("the day after tomorrow"),
NamedRelativeTime::DayBeforeYesterday => f.write_str("the day before yesterday"),
}
}
}
/// Represents a specific point in time offset by some known duration or period, such as
/// "tomorrow", "now", "next tuesday", "3 days after 2/5/2028 at 7:11 PM" etc..
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
pub enum RelativeTime {
/// e.g. "3 hours before 18/9/2024 at 4:32 PM", "7 days and 3 hours after tomorrow", "5
/// days ago", "9 years from now".
Directional {
/// The [Duration] (how long).
duration: Duration,
/// e.g. "from now", "ago", "after tomorrow".
dir: TimeDirection,
},
/// e.g. "the day before tomorrow", "now", "tomorrow", "yesterday".
Named(NamedRelativeTime),
/// e.g. "next wednesday", "next friday", "next year".
Next(RelativeTimeUnit),
/// e.g. "last month", "last tuesday", "last year".
Last(RelativeTimeUnit),
}
impl Parse for RelativeTime {
fn parse(input: ParseStream) -> Result<Self> {
let fork = input.fork();
if fork.peek(Ident) {
let ident1 = fork.parse::<Ident>().unwrap().to_string().to_lowercase();
match ident1.as_str() {
"next" | "last" => {
// next / last [unit]
input.parse::<Ident>()?;
let unit = input.parse::<RelativeTimeUnit>()?;
if ident1 == "next" {
return Ok(RelativeTime::Next(unit));
} else {
return Ok(RelativeTime::Last(unit));
}
}
"day" | "now" | "today" | "tomorrow" | "yesterday" | "the" => {
return Ok(RelativeTime::Named(input.parse::<NamedRelativeTime>()?))
}
_ => (),
}
}
let duration = input.parse::<Duration>()?;
let dir = input.parse::<TimeDirection>()?;
Ok(RelativeTime::Directional { duration, dir })
}
}
impl Display for RelativeTime {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self {
RelativeTime::Directional { duration, dir } => write!(f, "{duration} {dir}"),
RelativeTime::Next(unit) => write!(f, "next {unit}"),
RelativeTime::Last(unit) => write!(f, "last {unit}"),
RelativeTime::Named(named) => write!(f, "{named}"),
}
}
}
/// A `dd/mm/yyyy` style date.
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
pub struct Date(pub Month, pub DayOfMonth, pub Year);
impl Parse for Date {
fn parse(input: ParseStream) -> Result<Self> {
let day = input.parse::<DayOfMonth>()?;
input.parse::<Token![/]>()?;
let month = input.parse::<Month>()?;
input.parse::<Token![/]>()?;
let year = input.parse::<Year>()?;
Ok(Date(month, day, year))
}
}
impl Display for Date {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.write_fmt(format_args!("{}/{}/{}", self.1, self.0, self.2))
}
}
/// e.g. `22/4/1991 5:25 PM`, `22/4/1991 at 5:25 PM`, `22/4/1991 15:28`.
///
/// Note that "at" is optional and time can either be 12-hour (must have am/pm specified) or
/// 24-hour.
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
pub struct DateTime(pub Date, pub Time); // 22/4/1991 5:25 PM
impl Parse for DateTime {
fn parse(input: ParseStream) -> Result<Self> {
let date = input.parse::<Date>()?;
if input.peek(Ident) {
let ident = input.parse::<Ident>()?;
if ident.to_string().to_lowercase().as_str() != "at" {
return Err(Error::new(ident.span(), "expected `at`"));
}
}
let time = input.parse::<Time>()?;
Ok(DateTime(date, time))
}
}
impl Display for DateTime {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.write_fmt(format_args!("{} at {}", self.0, self.1))
}
}
/// A simple representation of the time, e.g. `13:07` or `5:07 PM`.
///
/// Both 24-hour and 12-hour are supported (must specify `AM` or `PM` when using 12-hour).
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
pub struct Time(pub Hour, pub Minute);
impl Parse for Time {
fn parse(input: ParseStream) -> Result<Self> {
let hour_lit = input.parse::<LitInt>()?;
let hour_val = hour_lit.base10_parse::<u8>()?;
input.parse::<Token![:]>()?;
let min = input.parse::<Minute>()?;
if input.peek(Ident)
&& ["am", "pm"].contains(
&input
.fork()
.parse::<Ident>()
.unwrap()
.to_string()
.to_lowercase()
.as_str(),
)
{
let am_pm = input.parse::<AmPm>()?;
if hour_val > 12 || hour_val == 0 {
return Err(Error::new(
hour_lit.span(),
"hour must be between 1 and 12 (inclusive)",
));
}
return Ok(Time(Hour::Hour12(hour_val, am_pm), min));
}
if hour_val > 24 {
return Err(Error::new(
hour_lit.span(),
"hour must be between 0 and 24 (inclusive)",
));
}
Ok(Time(Hour::Hour24(hour_val), min))
}
}
impl Display for Time {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self {
Time(Hour::Hour12(hour, am_pm), minute) => {
write!(f, "{}:{:02} {}", hour, minute, am_pm)
}
Time(Hour::Hour24(hour), minute) => write!(f, "{}:{:02}", hour, minute),
}
}
}
/// Represents a particular day of the month, which can range from 1 to 31.
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
pub struct DayOfMonth(pub u8);
impl Parse for DayOfMonth {
fn parse(input: ParseStream) -> Result<Self> {
let lit = input.parse::<LitInt>()?;
let int_val = lit.base10_parse::<u8>()?;
if int_val > 31 || int_val == 0 {
return Err(Error::new(
lit.span(),
"day must be between 1 and 31 (inclusive)",
));
}
Ok(DayOfMonth(int_val))
}
}
impl Display for DayOfMonth {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.write_fmt(format_args!("{}", self.0))
}
}
/// Represents a year, which can be any valid [`u16`].
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
pub struct Year(pub u16);
impl Parse for Year {
fn parse(input: ParseStream) -> Result<Self> {
let lit = input.parse::<LitInt>()?;
let int_val = lit.base10_parse::<u16>()?;
Ok(Year(int_val))
}
}
impl Display for Year {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.write_fmt(format_args!("{}", self.0))
}
}
/// Represents an hour of the day in either 12-hour or 24-hour format.
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
pub enum Hour {
/// 12-hour format, i.e. `5 PM`
Hour12(u8, AmPm),
/// 24-hour format, i.e. `18`
Hour24(u8),
}
impl Parse for Hour {
fn parse(input: ParseStream) -> Result<Self> {
let lit = input.parse::<LitInt>()?;
let int_val = lit.base10_parse::<u8>()?;
if let Ok(am_pm) = input.parse::<AmPm>() {
if int_val > 12 || int_val == 0 {
return Err(Error::new(
lit.span(),
"hour must be between 1 and 12 (inclusive)",
));
}
return Ok(Hour::Hour12(int_val, am_pm));
}
if int_val > 24 {
return Err(Error::new(
lit.span(),
"hour must be between 0 and 24 (inclusive)",
));
}
Ok(Hour::Hour24(int_val))
}
}
impl Display for Hour {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self {
Hour::Hour12(hour, am_pm) => f.write_fmt(format_args!("{hour} {am_pm}",)),
Hour::Hour24(hour) => f.write_fmt(format_args!("{hour}")),
}
}
}
/// Represents a minute of the hour, which can range from 0 to 60.
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
pub struct Minute(pub u8);
impl Parse for Minute {
fn parse(input: ParseStream) -> Result<Self> {
let lit = input.parse::<LitInt>()?;
let int_val = lit.base10_parse::<u8>()?;
if int_val > 60 {
return Err(Error::new(
lit.span(),
"minute must be between 0 and 60 (inclusive)",
));
}
Ok(Minute(int_val))
}
}
impl Display for Minute {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.write_fmt(format_args!("{:02}", self.0))
}
}
/// Represents a particular month of the year, which can range from 1-12
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
#[repr(u8)]
pub enum Month {
/// January (1)
January = 1,
/// February (2)
February,
/// March (3)
March,
/// April (4)
April,
/// May (5)
May,
/// June (6)
June,
/// July (7)
July,
/// August (8)
August,
/// September (9)
September,
/// October (10)
October,
/// November (11)
November,
/// December (12)
December,
}
impl Parse for Month {
fn parse(input: ParseStream) -> Result<Self> {
let lit = input.parse::<LitInt>()?;
let int_val = lit.base10_parse::<u8>()?;
if int_val > 12 || int_val == 0 {
return Err(Error::new(
lit.span(),
"month must be between 1 and 12 (inclusive)",
));
}
use Month::*;
Ok(match int_val {
1 => January,
2 => February,
3 => March,
4 => April,
5 => May,
6 => June,
7 => July,
8 => August,
9 => September,
10 => October,
11 => November,
12 => December,
_ => unreachable!(),
})
}
}
impl From<Month> for u8 {
fn from(value: Month) -> Self {
use Month::*;
match value {
January => 1,
February => 2,
March => 3,
April => 4,
May => 5,
June => 6,
July => 7,
August => 8,
September => 9,
October => 10,
November => 11,
December => 12,
}
}
}
impl From<&Month> for u8 {
fn from(value: &Month) -> Self {
(*value).into()
}
}
impl Display for Month {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
let as_u8: u8 = self.into();
f.write_fmt(format_args!("{}", as_u8))
}
}
/// Represents either AM or PM
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
pub enum AmPm {
/// AM
AM,
/// PM
PM,
}
impl Parse for AmPm {
fn parse(input: ParseStream) -> Result<Self> {
let ident = input.parse::<Ident>()?;
match ident.to_string().to_lowercase().as_str() {
"am" => Ok(AmPm::AM),
"pm" => Ok(AmPm::PM),
_ => Err(Error::new(ident.span(), "expected `AM` or `PM`")),
}
}
}
impl Display for AmPm {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self {
AmPm::AM => f.write_str("AM"),
AmPm::PM => f.write_str("PM"),
}
}
}
impl AsRef<str> for AmPm {
fn as_ref(&self) -> &str {
match self {
AmPm::AM => "AM",
AmPm::PM => "PM",
}
}
}
/// Represents particular units of time, such as hours, minutes, etc.
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
pub enum TimeUnit {
/// Minutes
Minutes,
/// Hours
Hours,
/// Days
Days,
/// Weeks
Weeks,
/// Months
Months,
/// Years
Years,
}
impl Parse for TimeUnit {
fn parse(input: ParseStream) -> Result<Self> {
let ident = input.parse::<Ident>()?;
use TimeUnit::*;
Ok(match ident.to_string().to_lowercase().as_str() {
"mins" | "minutes" | "minute" | "min" => Minutes,
"hours" | "hrs" | "hour" | "hr" => Hours,
"days" | "day" => Days,
"weeks" | "week" => Weeks,
"months" | "month" => Months,
"years" | "yr" | "year" => Years,
_ => {
return Err(Error::new(
ident.span(),
"expected one of `minutes`, `hours`, `days`, `weeks`, `months`, and `years`",
))
}
})
}
}
impl AsRef<str> for TimeUnit {
fn as_ref(&self) -> &str {
match self {
TimeUnit::Minutes => "minutes",
TimeUnit::Hours => "hours",
TimeUnit::Days => "days",
TimeUnit::Weeks => "minutes",
TimeUnit::Months => "months",
TimeUnit::Years => "years",
}
}
}
impl Display for TimeUnit {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.write_str(self.as_ref())
}
}
/// Enumerates the various types of relative times that can be paired with a [Duration].
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
pub enum TimeDirection {
/// e.g. `after 18/7/2025 at 3:22 PM`
AfterAbsolute(AbsoluteTime),
/// e.g. `before 18/7/2025 at 3:22 PM`
BeforeAbsolute(AbsoluteTime),
/// e.g. `after tomorrow`
AfterNamed(NamedRelativeTime),
/// e.g. `before yesterday`
BeforeNamed(NamedRelativeTime),
/// e.g. `before next tuesday`
BeforeNext(RelativeTimeUnit),
/// e.g. `before last week`
BeforeLast(RelativeTimeUnit),
/// e.g. `after next thursday`
AfterNext(RelativeTimeUnit),
/// e.g. `after last month`
AfterLast(RelativeTimeUnit),
/// Ago
Ago,
/// From now
FromNow,
}
impl Parse for TimeDirection {
fn parse(input: ParseStream) -> Result<Self> {
let ident1 = input.parse::<Ident>()?;
match ident1.to_string().to_lowercase().as_str() {
"after" => {
if input.peek(LitInt) {
Ok(TimeDirection::AfterAbsolute(input.parse()?))
} else {
let ident2 = input.fork().parse::<Ident>()?.to_string().to_lowercase();
match ident2.as_str() {
"next" => {
input.parse::<Ident>()?;
Ok(TimeDirection::AfterNext(input.parse()?))
}
"last" => {
input.parse::<Ident>()?;
Ok(TimeDirection::AfterLast(input.parse()?))
}
_ => Ok(TimeDirection::AfterNamed(input.parse()?)),
}
}
}
"before" => {
if input.peek(LitInt) {
Ok(TimeDirection::BeforeAbsolute(input.parse()?))
} else {
let ident2 = input.fork().parse::<Ident>()?.to_string().to_lowercase();
match ident2.as_str() {
"next" => {
input.parse::<Ident>()?;
Ok(TimeDirection::BeforeNext(input.parse()?))
}
"last" => {
input.parse::<Ident>()?;
Ok(TimeDirection::BeforeLast(input.parse()?))
}
_ => Ok(TimeDirection::BeforeNamed(input.parse()?)),
}
}
}
"ago" => Ok(TimeDirection::Ago),
"from" => {
let ident2 = input.parse::<Ident>()?;
if ident2.to_string().to_lowercase().as_str() != "now" {
return Err(Error::new(ident2.span(), "expected `now`"));
}
Ok(TimeDirection::FromNow)
}
_ => Err(Error::new(
ident1.span(),
"expected one of `after`, `before`, `ago`, `from`",
)),
}
}
}
impl Display for TimeDirection {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self {
TimeDirection::AfterAbsolute(abs_time) => write!(f, "after {abs_time}"),
TimeDirection::BeforeAbsolute(abs_time) => write!(f, "before {abs_time}"),
TimeDirection::Ago => f.write_str("ago"),
TimeDirection::FromNow => f.write_str("from now"),
TimeDirection::AfterNamed(named) => write!(f, "after {named}"),
TimeDirection::BeforeNamed(named) => write!(f, "before {named}"),
TimeDirection::BeforeNext(unit) => write!(f, "before next {unit}"),
TimeDirection::BeforeLast(unit) => write!(f, "before last {unit}"),
TimeDirection::AfterNext(unit) => write!(f, "after next {unit}"),
TimeDirection::AfterLast(unit) => write!(f, "after last {unit}"),
}
}
}
/// Represents a positive integer, stored as a [`u64`].
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
pub struct Number(pub u64);
impl From<u64> for Number {
fn from(value: u64) -> Self {
Number(value)
}
}
impl From<Number> for u64 {
fn from(value: Number) -> Self {
value.0
}
}
impl Add for Number {
type Output = Number;
fn add(self, rhs: Self) -> Self::Output {
Number(self.0 + rhs.0)
}
}
impl Sub for Number {
type Output = Number;
fn sub(self, rhs: Self) -> Self::Output {
Number(self.0 - rhs.0)
}
}
impl Mul for Number {
type Output = Number;
fn mul(self, rhs: Self) -> Self::Output {
Number(self.0 * rhs.0)
}
}
impl Div for Number {
type Output = Number;
fn div(self, rhs: Self) -> Self::Output {
Number(self.0 / rhs.0)
}
}
impl PartialEq<u64> for Number {
fn eq(&self, other: &u64) -> bool {
self.0 == *other
}
}
impl PartialOrd<u64> for Number {
fn partial_cmp(&self, other: &u64) -> Option<std::cmp::Ordering> {
self.0.partial_cmp(other)
}
}
impl Parse for Number {
fn parse(input: ParseStream) -> Result<Self> {
let lit = input.parse::<LitInt>()?;
let int_val = lit.base10_parse::<u64>()?;
Ok(Number(int_val))
}
}
impl Display for Number {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.write_fmt(format_args!("{}", self.0))
}
}
macro_rules! impl_parse_str {
($ident:ident) => {
impl FromStr for $ident {
type Err = syn::Error;
fn from_str(s: &str) -> std::prelude::v1::Result<Self, Self::Err> {
syn::parse_str(s)
}
}
};
}
impl_parse_str!(TimeExpression);
impl_parse_str!(TimeDirection);
impl_parse_str!(TimeUnit);
impl_parse_str!(TimeRange);
impl_parse_str!(AmPm);
impl_parse_str!(DayOfMonth);
impl_parse_str!(Minute);
impl_parse_str!(Month);
impl_parse_str!(Hour);
impl_parse_str!(AbsoluteTime);
impl_parse_str!(Duration);
impl_parse_str!(RelativeTime);
impl_parse_str!(PointInTime);
impl_parse_str!(Time);
impl_parse_str!(DateTime);
impl_parse_str!(RelativeTimeUnit);
impl_parse_str!(NamedRelativeTime);
#[cfg(test)]
macro_rules! assert_impl_all {
($($typ:ty),* : $($tt:tt)*) => {{
const fn _assert_impl<T>() where T: $($tt)*, {}
$(_assert_impl::<$typ>();)*
}};
}
#[test]
fn test_traits() {
assert_impl_all!(
TimeDirection,
TimeUnit,
AmPm,
DayOfMonth,
Minute,
Month,
Hour,
AbsoluteTime,
Duration,
RelativeTime,
PointInTime,
Time,
DateTime,
RelativeTimeUnit,
NamedRelativeTime,
TimeRange,
TimeExpression : Copy
+ Clone
+ PartialEq
+ Eq
+ PartialOrd
+ Ord
+ core::fmt::Debug
+ core::fmt::Display
+ Parse
+ core::hash::Hash
+ FromStr
);
}