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use crate::time;
use std::fmt::{self, Display};
use std::num::ParseIntError;
use std::str::FromStr;
use syn::parse::{Error, Parse, ParseStream};
use syn::{LitInt, Token};
#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
pub struct Date {
pub year: u16,
pub month: u8,
pub day: u8,
}
impl Display for Date {
fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
write!(
formatter,
"{:04}-{:02}-{:02}",
self.year, self.month, self.day,
)
}
}
pub struct ParseDateError;
impl From<ParseIntError> for ParseDateError {
fn from(_err: ParseIntError) -> Self {
ParseDateError
}
}
impl FromStr for Date {
type Err = ParseDateError;
fn from_str(s: &str) -> Result<Self, Self::Err> {
let mut date = s.split('-');
let year = date.next().ok_or(ParseDateError)?.parse()?;
let month = date.next().ok_or(ParseDateError)?.parse()?;
let day = date.next().ok_or(ParseDateError)?.parse()?;
match date.next() {
None => Ok(Date { year, month, day }),
Some(_) => Err(ParseDateError),
}
}
}
impl Parse for Date {
fn parse(input: ParseStream) -> syn::Result<Self> {
let span = input.cursor().token_stream();
let error = || {
Error::new_spanned(
&span,
format!("expected nightly date, like {}", time::today()),
)
};
let year: LitInt = input.parse().map_err(|_| error())?;
input.parse::<Token![-]>()?;
let month: LitInt = input.parse().map_err(|_| error())?;
input.parse::<Token![-]>()?;
let day: LitInt = input.parse().map_err(|_| error())?;
let year = year.base10_parse::<u64>().map_err(|_| error())?;
let month = month.base10_parse::<u64>().map_err(|_| error())?;
let day = day.base10_parse::<u64>().map_err(|_| error())?;
if year >= 3000 || month > 12 || day > 31 {
return Err(error());
}
Ok(Date {
year: year as u16,
month: month as u8,
day: day as u8,
})
}
}
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