atar-axis / yaml-cpp-path

for yaml-cpp, a convenient way to select sub nodes.

yaml-path

YAML is a structured document format.
yaml-cpp (by jbeder) is a C++ library to read and write YAML files.
yaml-path extends yaml-cpp, making it easier to select content from a YAML file.

yaml-path requires C++ 17.

What's the point?

The central addition of yaml-path is a function

Node Select(Node n, path_arg path)

That uses path (a string) to select one or more nodes from n. e.g.

// example data: 
Nore root = Load(R"(
-  name : Joe
   color: red
   names: 
      first : Joe
	  middle : Joeboy
	  last: Joeson
-  name : Sina
   color: blue
   names: 4
-  name : Estragon
   voice : none)";      
)");

Node result = Select(root, "name"); 
// --> returns a list ["Joe", "Sina", "Estragon"]

Node result = Select(root, "[0].names.middle"); 
// --> returns a scalar "Joeboy"

Note: Node from yaml-cpp represents a document node of a YAML document. Load from yaml-cpp loads text as YAML document and returns a Node. All symbols are defined in the YAML namespace.

Status:

Used in production. currently implements the initially required/envisioned features, some ideas (yaml-path\readme.txt) are pending. I'm still willing to break syntaxt, esp. the path specification.

Getting Started

The folder yaml-path contains all the sources that you need to add to your project. Make sure #include <yaml-cpp/yaml.h> finds the yaml-cpp headers, and link to the yaml-cpp library.

test.cpp contains tests, using doctest.

There is no make script.
The "msvc" branch contains a MSVC 2017 project that includes a snapshot of yaml-cpp and doctest. It's always ahead of master, and matches the current master (in other words, there's real history of that)

In the github "Releases" section, you find

• doxygen documentation, including full specification of selectors
• a precompiled Windows x86binary that allows to test and play around with yaml paths.

Examples

For a YAML document of

- name: Joe
  color: red
  friends: ~
- name: Sina
  color: blue
- name: Estragon
  color: red
  friends:
	Wladimir: good
	Godot: unreliable

this is a list of example paths and the nodes they return:

Path: "name"

- Joe
- Sina
- Estragon

Path: "[1].name"

Sina

Path: "name[2]"

Estragon

Path: "color"

- red
- blue
- red

Path: "{color=red}"

- name: Joe
  color: red
  friends: ~
- name: Estragon
  color: red
  friends:
	Wladimir: good
	Godot: unreliable

Path: "{color=blue}"

- name: Sina
  color: blue

Path: "{friends=}"

- name: Joe
  color: red
  friends: ~
- name: Estragon
  color: red
  friends:
	Wladimir: good
	Godot: unreliable

Path: "friends.Wladimir"

- good

Path: "friends.Wladimir[0]"

unreliable

Path: "[1]"

- name: Sina
  color: blue

Path: "[1].color"

  blue

License

This project is licensed under the MIT License - see the LICENSE.md file for details