Fix source spans for scalars.

Closes #13

R=pquitslund@google.com, rnystrom@google.com

Review URL: https://codereview.chromium.org//1329183002 .

CHANGELOG.md

@@ -1,3 +1,8 @@
+## 2.1.5
+
+* Fix a bug with 2.1.4 where source span information was being discarded for
+  scalar values.
+
 ## 2.1.4
 
 * Substantially improve performance.

lib/src/yaml_node.dart

@@ -166,7 +166,7 @@ class YamlScalar extends YamlNode {
   /// Users of the library should not use this constructor.
   YamlScalar.internal(this.value, ScalarEvent scalar)
       : style = scalar.style {
-    _span = span;
+    _span = scalar.span;
   }
 
   /// Users of the library should not use this constructor.

pubspec.yaml

@@ -1,5 +1,5 @@
 name: yaml
-version: 2.1.4
+version: 2.1.5
 author: "Dart Team <misc@dartlang.org>"
 homepage: https://github.com/dart-lang/yaml
 description: A parser for YAML.

test/yaml_test.dart

@@ -54,6 +54,43 @@ main() {
     });
   });
 
+  test("includes source span information", () {
+    var yaml = loadYamlNode(r"""
+- foo:
+    bar
+- 123
+""");
+
+    expect(yaml.span.start.line, equals(0));
+    expect(yaml.span.start.column, equals(0));
+    expect(yaml.span.end.line, equals(3));
+    expect(yaml.span.end.column, equals(0));
+
+    var map = yaml.nodes.first;
+    expect(map.span.start.line, equals(0));
+    expect(map.span.start.column, equals(2));
+    expect(map.span.end.line, equals(2));
+    expect(map.span.end.column, equals(0));
+
+    var key = map.nodes.keys.first;
+    expect(key.span.start.line, equals(0));
+    expect(key.span.start.column, equals(2));
+    expect(key.span.end.line, equals(0));
+    expect(key.span.end.column, equals(5));
+
+    var value = map.nodes.values.first;
+    expect(value.span.start.line, equals(1));
+    expect(value.span.start.column, equals(4));
+    expect(value.span.end.line, equals(1));
+    expect(value.span.end.column, equals(7));
+
+    var scalar = yaml.nodes.last;
+    expect(scalar.span.start.line, equals(2));
+    expect(scalar.span.start.column, equals(2));
+    expect(scalar.span.end.line, equals(2));
+    expect(scalar.span.end.column, equals(5));
+  });
+
   // The following tests are all taken directly from the YAML spec
   // (http://www.yaml.org/spec/1.2/spec.html). Most of them are code examples
   // that are directly included in the spec, but additional tests are derived