Add std::str::is_whitespace

src/lib/str.rs

@@ -52,6 +52,7 @@ export bytes_ivec;
 export unsafe_from_bytes_ivec;
 export is_empty;
 export is_not_empty;
+export is_whitespace;
 export replace;
 export char_slice;
 export trim_left;
@@ -166,6 +167,18 @@ pred is_empty(s: str) -> bool { for c: u8  in s { ret false; } ret true; }
 /// Returns true if the string has length greater than 0
 pred is_not_empty(s: str) -> bool { !is_empty(s) }
 
+fn is_whitespace(s: str) -> bool {
+    let i = 0u;
+    let len = char_len(s);
+    while i < len {
+        if !char::is_whitespace(char_at(s, i)) {
+            ret false;
+        }
+        i += 1u
+    }
+    ret true;
+}
+
 // Returns the number of bytes (a.k.a. UTF-8 code units) in s.
 // Contrast with a function that would return the number of code
 // points (char's), combining character sequences, words, etc.  See

src/test/stdtest/str.rs

@@ -192,6 +192,15 @@ fn trim() {
     assert str::trim(" hey dude ") == "hey dude";
 }
 
+#[test]
+fn is_whitespace() {
+    assert str::is_whitespace("");
+    assert str::is_whitespace(" ");
+    assert str::is_whitespace("\u2009"); // Thin space
+    assert str::is_whitespace("  \n\t   ");
+    assert !str::is_whitespace("   _   ");
+}
+
 // Local Variables:
 // mode: rust;
 // fill-column: 78;