Loading a YamlSourceNode topic

YAML allows nodes to be declared using a block or flow style. You can use flow styles in block but not the other way around. Types of node include:

1. Scalar - anything that is not a map/list in Dart
2. Sequence - list in Dart. Set support not yet available
3. Mapping - map in Dart

Scalars

Any node that is not a Sequence or Mapping. By default, its type is inferred out of the box.

final node = loadYamlNode<Scalar>(source: '24');
print(yamlCollectionEquality.equals(24, node)); // True.

Sequences (Lists)

An immutable list. Allows all node types to be used.

import 'package:collection/collection.dart';

const yaml = '''
- rookie_yaml. The
- new kid
- in town
''';

final node = loadYamlNode<Sequence>(source: yaml);

// True.
print(
  yamlCollectionEquality.equals(node, [
    'rookie_yaml. The',
    'new kid',
    'in town',
  ]),
);

Mapping (Map)

An immutable map. Allows any node type as a key or value just like a Dart map.

// Let's get funky.
const mappy = {
  'name': 'rookie_yaml',
  'in_active_development': true,
  'supports':  {
    1: 'Full YAML spec',
    2: 'Custom tags and resolvers',
  }
};

// Built-in Dart types as strings are just flow nodes in yaml
final node = loadYamlNode<Mapping>(source: mappy.toString());

// True.
print(yamlCollectionEquality.equals(node, mappy));