diff options
Diffstat (limited to 'rustversion/src/date.rs')
-rw-r--r-- | rustversion/src/date.rs | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/rustversion/src/date.rs b/rustversion/src/date.rs new file mode 100644 index 0000000..631b762 --- /dev/null +++ b/rustversion/src/date.rs @@ -0,0 +1,77 @@ +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, + }) + } +} |