| // Copyright 2018 The Fuchsia Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| /// Interface implemented by all Sledge Values. |
| /// |
| /// Values are used to store the structure and content of the fields of a |
| /// Document. |
| /// |
| /// There are two main types of Values: NodeValues, and LeafValues. |
| /// Every Sledge Document holds a reference to a NodeValue. |
| /// The NodeValues hold references to at least one other Value (either a |
| /// NodeValue or a LeafValue). |
| /// The LeafValues store the actual content of the fields. |
| /// |
| /// For example, a Document whose fields can be accessed the following way: |
| /// doc['a'].value = 1; |
| /// doc['b']['c'].value = 2.0; |
| /// doc['b']['d'].value = 'foobar'; |
| /// Will be composed of 2 NodeValues and 3 LeafValues: |
| /// doc |
| /// └─NodeValue |
| /// ├─ 'a' : LeafValue (specialized for integers) |
| /// └─ 'b' : NodeValue |
| /// ├─ 'c' : LeafValue (specialized for doubles) |
| /// └─ 'd' : LeafValue (specialized for strings) |
| abstract class Value {} |
