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,
+        })
+    }
+}