Fix source spans for scalars.

test/yaml_test.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library yaml.test;
 
 import 'package:test/test.dart';
 import 'package:yaml/yaml.dart';
 
 import 'utils.dart';
@@ skipping 36 matching lines @@
     });
 
     test("2.0", () {
       expectYamlFails("""
          %YAML 2.0
          --- text
          """);
     });
   });
 
+  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
   // from the prose.
 
   // A few examples from the spec are deliberately excluded, because they test
   // features that this implementation doesn't intend to support (character
   // encoding detection and user-defined tags). More tests are commented out,
   // because they're intended to be supported but not yet implemented.
 
@@ skipping 1772 matching lines @@
         A null: null
         Also a null: # Empty
         Not a null: ""
         Booleans: [ true, True, false, FALSE ]
         Integers: [ 0, 0o7, 0x3A, -19 ]
         Floats: [ 0., -0.0, .5, +12e03, -2E+05 ]
         Also floats: [ .inf, -.Inf, +.INF, .NAN ]''');
     });
   });
 }