add try_from/try_into

src/lib.rs

@@ -1,6 +1,7 @@
 #[macro_use] extern crate quick_error;
 use chrono::prelude::*;
 use std::{
+    convert::TryFrom,
     time::Duration,
     str::Chars,
     iter::Peekable,
@@ -181,6 +182,14 @@ pub fn fmt(f: &str) -> Result<SimpleDateFormat, ParseError> {
     Ok(SimpleDateFormat{ parts })
 }
 
+impl TryFrom<&str> for SimpleDateFormat {
+    type Error = ParseError;
+
+    fn try_from(s: &str) -> Result<Self, Self::Error> {
+        SimpleDateFormat::new(s)
+    }
+}
+
 fn format_zone<Tz>(date_time: &DateTime<Tz>, _cnt: usize) -> String where Tz: TimeZone {
     format!("{:?}", date_time.offset())
 }

tests/lib_test.rs

@@ -1,4 +1,4 @@
-use simpledateformat::{ fmt, format_human, };
+use simpledateformat::{ SimpleDateFormat, fmt, format_human, };
 use chrono::prelude::*;
 use std::time::Duration;
 
@@ -35,3 +35,12 @@ fn test_format_human() {
     assert_eq!("2days", format_human(Duration::from_secs(2 * 24 * 60 * 60)));
     assert_eq!("2days 0hour 0min 1s", format_human(Duration::from_secs(2 * 24 * 60 * 60 + 1)));
 }
+
+#[test]
+fn test_try_from() {
+    use std::convert::TryInto;
+    let t = Utc.timestamp_millis(0);
+    let fmt = "yyyy/MM/dd HH:mm:ss.SSS z";
+    let sdf: Result<SimpleDateFormat, _> = fmt.try_into();
+    assert_eq!("1970/01/01 00:00:00.000 Z", sdf.unwrap().format(&t));
+}