Add a "skip whitespace" iterator that also ignores source locations.

Author: SimonSapin

ast.rs

@@ -3,6 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use std::str::ToStr;
+use std::vec;
 
 
 #[deriving(Eq)]
@@ -114,3 +115,30 @@ pub enum ErrorReason {
 impl ToStr for ErrorReason {
     fn to_str(&self) -> ~str { fmt!("%?", self) }
 }
+
+
+pub trait SkipWhitespaceIterable<'self> {
+    pub fn skip_whitespace(self) -> SkipWhitespaceIterator<'self>;
+}
+
+impl<'self> SkipWhitespaceIterable<'self> for &'self [(ComponentValue, SourceLocation)] {
+    pub fn skip_whitespace(self) -> SkipWhitespaceIterator<'self> {
+        SkipWhitespaceIterator{ iter: self.iter() }
+    }
+}
+
+struct SkipWhitespaceIterator<'self> {
+    iter: vec::VecIterator<'self, (ComponentValue, SourceLocation)>,
+}
+
+impl<'self> Iterator<&'self ComponentValue> for SkipWhitespaceIterator<'self> {
+    fn next(&mut self) -> Option<&'self ComponentValue> {
+        loop {
+            match self.iter.next() {
+                Some(&(WhiteSpace, _)) => (),
+                Some(&(ref component_value, _)) => return Some(component_value),
+                None => return None
+            }
+        }
+    }
+}

color.rs

@@ -87,9 +87,7 @@ fn parse_color_function(name: &str, arguments: &[(ComponentValue, SourceLocation
         else if "hsla" == lower_name { (false, true) }
         else { return None };
 
-    let mut iter = do arguments.iter().filter_map |&(ref c, _)| {
-        if c != &WhiteSpace { Some(c) } else { None }
-    };
+    let mut iter = arguments.skip_whitespace();
     macro_rules! expect_comma(
         () => ( if iter.next() != Some(&Comma) { return None } );
     )