Add old rust versions to test agains

.travis.yml

@@ -74,6 +74,23 @@ matrix:
       os: osx
       rust: beta
 
+    # Historical Rust versions
+    - env: TARGET=x86_64-unknown-linux-gnu
+      rust: 1.21.0
+    - env: TARGET=x86_64-unknown-linux-gnu
+      rust: 1.22.0
+    - env: TARGET=x86_64-unknown-linux-gnu
+      rust: 1.23.0
+    - env: TARGET=x86_64-unknown-linux-gnu
+      rust: 1.24.0
+    - env: TARGET=x86_64-unknown-linux-gnu
+      rust: 1.25.0
+    - env: TARGET=x86_64-unknown-linux-gnu
+      rust: 1.26.0
+    - env: TARGET=x86_64-unknown-linux-gnu
+      rust: 1.27.0
+    
+
 before_install:
   - set -e
   - rustup self update

README.md

@@ -65,5 +65,11 @@ assert_eq!(
 
 Further examples can be found in the [examples](examples) directory on international usage.
 
+# Usage
+
+`dtparse` requires a minimum Rust version of 1.21 to build, but is tested on Windows, OSX,
+BSD, and Linux. The build is also compiled against the iOS and Android SDK's, but is not
+tested against them.
+
 [dateutil]: https://github.com/dateutil/dateutil
 [examples]: https://github.com/bspeice/dtparse/tree/master/examples

src/lib.rs

@@ -10,7 +10,7 @@
 //! sense of the dates and times they contain. A couple of quick examples
 //! from the test cases should give some context:
 //! 
-//! ```rust
+//! ```rust,ignore (tests-dont-compile-on-old-rust)
 //! # extern crate chrono;
 //! # extern crate dtparse;
 //! use chrono::prelude::*;
@@ -34,7 +34,7 @@
 //! And we can even handle fuzzy strings where dates/times aren't the
 //! only content if we dig into the implementation a bit!
 //! 
-//! ```rust
+//! ```rust,ignore (tests-dont-compile-on-old-rust)
 //! # extern crate chrono;
 //! # extern crate dtparse;
 //! use chrono::prelude::*;

src/weekday.rs

@@ -16,13 +16,13 @@ impl DayOfWeek {
 
     pub fn to_numeral(&self) -> u32 {
         match self {
-            DayOfWeek::Sunday => 0,
+            &DayOfWeek::Sunday => 0,
-            DayOfWeek::Monday => 1,
+            &DayOfWeek::Monday => 1,
-            DayOfWeek::Tuesday => 2,
+            &DayOfWeek::Tuesday => 2,
-            DayOfWeek::Wednesday => 3,
+            &DayOfWeek::Wednesday => 3,
-            DayOfWeek::Thursday => 4,
+            &DayOfWeek::Thursday => 4,
-            DayOfWeek::Friday => 5,
+            &DayOfWeek::Friday => 5,
-            DayOfWeek::Saturday => 6,
+            &DayOfWeek::Saturday => 6,
         }
     }