Index<usize> for LineString to get the coordinate at that position

amandasaurus · Feb 13, 2019 · c4f27e9 · c4f27e9
1 parent 96c7846
commit c4f27e9
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diff --git a/geo-types/src/lib.rs b/geo-types/src/lib.rs
@@ -113,8 +113,13 @@ mod test {
         let _: MultiPoint<_> = vec![(0., 0.), (1., 2.)].into();
         let _: MultiPoint<_> = vec![(0., 0.), (1., 2.)].into_iter().collect();
 
-        let _: LineString<_> = vec![(0., 0.), (1., 2.)].into();
+        let mut l1: LineString<_> = vec![(0., 0.), (1., 2.)].into();
+        assert_eq!(l1[1], Coordinate{ x: 1., y: 2. });   // index into linestring
         let _: LineString<_> = vec![(0., 0.), (1., 2.)].into_iter().collect();
+
+        // index mutably into a linestring
+        l1[0] = Coordinate{ x: 1., y: 1. };
+        assert_eq!(l1, vec![(1., 1.), (1., 2.)].into());
     }
 
     #[test]

diff --git a/geo-types/src/line_string.rs b/geo-types/src/line_string.rs
@@ -1,4 +1,5 @@
 use std::iter::FromIterator;
+use std::ops::{Index, IndexMut};
 use {Coordinate, CoordinateType, Line, Point, Triangle};
 
 /// An ordered collection of two or more [`Coordinate`s](struct.Coordinate.html), representing a
@@ -174,6 +175,21 @@ impl<T: CoordinateType> IntoIterator for LineString<T> {
     }
 }
 
+impl<T: CoordinateType> Index<usize> for LineString<T> {
+    type Output = Coordinate<T>;
+
+    fn index(&self, index: usize) -> &Coordinate<T> {
+        self.0.index(index)
+    }
+}
+
+impl<T: CoordinateType> IndexMut<usize> for LineString<T> {
+    fn index_mut(&mut self, index: usize) -> &mut Coordinate<T> {
+        self.0.index_mut(index)
+    }
+}
+
+
 #[cfg(feature = "rstar")]
 impl<T> ::rstar::RTreeObject for LineString<T>
 where