Merge pull request #186 from yuankunzhang/improve-literal-date-parser

feat: improve the literal date parsers

src/items/date.rs

@@ -27,17 +27,15 @@
 //! > ‘September’.
 
 use winnow::{
-    ascii::alpha1,
-    combinator::{alt, opt, preceded, trace},
+    ascii::{alpha1, multispace1},
+    combinator::{alt, eof, opt, preceded, terminated, trace},
     error::ErrMode,
-    seq,
     stream::AsChar,
     token::take_while,
     ModalResult, Parser,
 };
 
 use super::primitive::{ctx_err, dec_uint, s};
-use crate::ParseDateTimeError;
 
 #[derive(PartialEq, Eq, Clone, Debug, Default)]
 pub struct Date {
@@ -220,27 +218,58 @@ fn us(input: &mut &str) -> ModalResult<Date> {
     }
 }
 
-/// Parse `14 November 2022`, `14 Nov 2022`, "14nov2022", "14-nov-2022", "14-nov2022", "14nov-2022"
+/// Parse `14 November 2022`, `14 Nov 2022`, "14nov2022", "14-nov-2022",
+/// "14-nov2022", "14nov-2022".
 fn literal1(input: &mut &str) -> ModalResult<Date> {
-    seq!(Date {
-        day: day,
-        _: opt(s('-')),
-        month: literal_month,
-        year: opt(preceded(opt(s('-')), year)),
-    })
-    .parse_next(input)
+    let (day, _, month, year) = (
+        s(dec_uint),
+        opt(s('-')),
+        s(literal_month),
+        opt(terminated(
+            preceded(opt(s('-')), s(take_while(1.., AsChar::is_dec_digit))),
+            // The year must be followed by a space or end of input.
+            alt((multispace1, eof)),
+        )),
+    )
+        .parse_next(input)?;
+
+    match year {
+        Some(year) => (year, month, day)
+            .try_into()
+            .map_err(|e| ErrMode::Cut(ctx_err(e))),
+        None => (month, day)
+            .try_into()
+            .map_err(|e| ErrMode::Cut(ctx_err(e))),
+    }
 }
 
-/// Parse `November 14, 2022` and `Nov 14, 2022`
+/// Parse `November 14, 2022`, `Nov 14, 2022`, and `Nov 14 2022`.
 fn literal2(input: &mut &str) -> ModalResult<Date> {
-    seq!(Date {
-        month: literal_month,
-        day: day,
-        // FIXME: GNU requires _some_ space between the day and the year,
-        // probably to distinguish with floats.
-        year: opt(preceded(s(","), year)),
-    })
-    .parse_next(input)
+    let (month, day, year) = (
+        s(literal_month),
+        s(dec_uint),
+        opt(terminated(
+            preceded(
+                // GNU quirk: for formats like `Nov 14, 2022`, there must be some
+                // space between the comma and the year. This is probably to
+                // distinguish with floats.
+                opt(s(terminated(',', multispace1))),
+                s(take_while(1.., AsChar::is_dec_digit)),
+            ),
+            // The year must be followed by a space or end of input.
+            alt((multispace1, eof)),
+        )),
+    )
+        .parse_next(input)?;
+
+    match year {
+        Some(year) => (year, month, day)
+            .try_into()
+            .map_err(|e| ErrMode::Cut(ctx_err(e))),
+        None => (month, day)
+            .try_into()
+            .map_err(|e| ErrMode::Cut(ctx_err(e))),
+    }
 }
 
 pub fn year(input: &mut &str) -> ModalResult<u32> {
@@ -268,17 +297,6 @@ pub fn year(input: &mut &str) -> ModalResult<u32> {
     .parse_next(input)
 }
 
-fn day(input: &mut &str) -> ModalResult<u32> {
-    s(dec_uint)
-        .try_map(|x| {
-            (1..=31)
-                .contains(&x)
-                .then_some(x)
-                .ok_or(ParseDateTimeError::InvalidInput)
-        })
-        .parse_next(input)
-}
-
 /// Parse the name of a month (case-insensitive)
 fn literal_month(input: &mut &str) -> ModalResult<u32> {
     s(alpha1)
@@ -462,6 +480,110 @@ mod tests {
         }
     }
 
+    #[test]
+    fn literal1() {
+        let reference = Date {
+            year: Some(2022),
+            month: 11,
+            day: 14,
+        };
+
+        for mut s in [
+            "14 november 2022",
+            "14 nov 2022",
+            "14-nov-2022",
+            "14-nov2022",
+            "14nov2022",
+            "14nov      2022",
+        ] {
+            let old_s = s.to_owned();
+            assert_eq!(parse(&mut s).unwrap(), reference, "Format string: {old_s}");
+        }
+
+        let reference = Date {
+            year: None,
+            month: 11,
+            day: 14,
+        };
+
+        for mut s in ["14 november", "14 nov", "14-nov", "14nov"] {
+            let old_s = s.to_owned();
+            assert_eq!(parse(&mut s).unwrap(), reference, "Format string: {old_s}");
+        }
+
+        let reference = Date {
+            year: None,
+            month: 11,
+            day: 14,
+        };
+
+        // Year must be followed by a space or end of input.
+        let mut s = "14 nov 2022a";
+        let old_s = s.to_owned();
+        assert_eq!(parse(&mut s).unwrap(), reference, "Format string: {old_s}");
+        assert_eq!(s, " 2022a");
+
+        let mut s = "14 nov-2022a";
+        let old_s = s.to_owned();
+        assert_eq!(parse(&mut s).unwrap(), reference, "Format string: {old_s}");
+        assert_eq!(s, "-2022a");
+    }
+
+    #[test]
+    fn literal2() {
+        let reference = Date {
+            year: Some(2022),
+            month: 11,
+            day: 14,
+        };
+
+        for mut s in [
+            "november 14 2022",
+            "november 14, 2022",
+            "november 14     ,     2022",
+            "nov 14 2022",
+            "nov14 2022",
+            "nov14, 2022",
+        ] {
+            let old_s = s.to_owned();
+            assert_eq!(parse(&mut s).unwrap(), reference, "Format string: {old_s}");
+        }
+
+        let reference = Date {
+            year: None,
+            month: 11,
+            day: 14,
+        };
+
+        for mut s in ["november 14", "nov 14", "nov14"] {
+            let old_s = s.to_owned();
+            assert_eq!(parse(&mut s).unwrap(), reference, "Format string: {old_s}");
+        }
+
+        let reference = Date {
+            year: None,
+            month: 11,
+            day: 14,
+        };
+
+        // There must be some space between the comma and the year.
+        let mut s = "november 14,2022";
+        let old_s = s.to_owned();
+        assert_eq!(parse(&mut s).unwrap(), reference, "Format string: {old_s}");
+        assert_eq!(s, ",2022");
+
+        // Year must be followed by a space or end of input.
+        let mut s = "november 14 2022a";
+        let old_s = s.to_owned();
+        assert_eq!(parse(&mut s).unwrap(), reference, "Format string: {old_s}");
+        assert_eq!(s, " 2022a");
+
+        let mut s = "november 14, 2022a";
+        let old_s = s.to_owned();
+        assert_eq!(parse(&mut s).unwrap(), reference, "Format string: {old_s}");
+        assert_eq!(s, ", 2022a");
+    }
+
     #[test]
     fn with_year() {
         let reference = Date {

src/items/mod.rs

@@ -97,7 +97,7 @@ pub(crate) fn at_local(
 /// item = datetime | date | time | relative | weekday | timezone | year ;
 ///
 /// datetime = date , [ "T" | "t" | whitespace ] , iso_time ;
-/// date = iso_date | us_date ;
+/// date = iso_date | us_date | literal1_date | literal2_date ;
 ///
 /// iso_date = year , [ iso_date_delim ] , month , [ iso_date_delim ] , day ;
 /// iso_date_delim = [ { whitespace } ] , "-" , [ { whitespace } ] ;
@@ -105,9 +105,28 @@ pub(crate) fn at_local(
 /// us_date = month , [ us_date_delim ] , day , [ [ us_date_delim ] , year ];
 /// us_date_delim = [ { whitespace } ] , "/" , [ { whitespace } ] ;
 ///
+/// literal1_date = day , [ literal1_date_delim ] , literal_month , [ [ literal1_date_delim ] , year ] ;
+/// literal1_date_delim = { whitespace } | [ { whitespace } ] , "-" , [ { whitespace } ] ;
+///
+/// literal2_date = literal_month , [ { whitespace } ] , day , [ [ literal2_date_delim ] , year ] ;
+/// literal2_date_delim = { whitespace } | [ { whitespace } ] , "," , [ { whitespace } ] ;
+///
 /// year = dec_int ;
 /// month = dec_int ;
 /// day = dec_int ;
+///
+/// literal_month = "january" | "jan"
+///               | "february" | "feb"
+///               | "march" | "mar"
+///               | "april" | "apr"
+///               | "may"
+///               | "june" | "jun"
+///               | "july" | "jul"
+///               | "august" | "aug"
+///               | "september" | "sept" | "sep"
+///               | "october" | "oct"
+///               | "november" | "nov"
+///               | "december" | "dec" ;
 /// ```
 pub(crate) fn parse(input: &mut &str) -> ModalResult<DateTimeBuilder> {
     trace("parse", alt((parse_timestamp, parse_items))).parse_next(input)