Merge pull request #23 from alexreg/master

Added `ArrayString::from` constructor that takes string slice.

src/array_string.rs

@@ -45,6 +45,24 @@ impl<A: Array<Item=u8>> ArrayString<A> {
         }
     }
 
+    /// Create a new `ArrayString` from a string slice.
+    ///
+    /// Capacity is inferred from the type parameter.
+    ///
+    /// ```
+    /// use arrayvec::ArrayString;
+    ///
+    /// let mut string = ArrayString::<[_; 3]>::from("foo").unwrap();
+    /// assert_eq!(&string[..], "foo");
+	/// assert_eq!(string.len(), 3);
+    /// assert_eq!(string.capacity(), 3);
+    /// ```
+	pub fn from(s: &str) -> Result<Self, CapacityError<&str>> {
+		let mut arraystr = Self::new();
+		try!(arraystr.push_str(s));
+		Ok(arraystr)
+	}
+
     /// Return the capacity of the `ArrayString`.
     ///
     /// ```

tests/tests.rs

@@ -288,7 +288,6 @@ fn test_string() {
     let tmut: &mut str = &mut t;
     assert_eq!(tmut, "ab");
 
-
     // Test Error trait / try
     let t = || -> Result<(), Box<Error>> {
         let mut t = ArrayString::<[_; 2]>::new();
@@ -296,4 +295,9 @@ fn test_string() {
         Ok(())
     }();
     assert!(t.is_err());
+
+	// Test `from` constructor
+    let u = ArrayString::<[_; 11]>::from(text).unwrap();
+	assert_eq!(&u, text);
+    assert_eq!(u.len(), text.len());
 }