|
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150 |
- # YAML support for the Go language
-
- Introduction
- ------------
-
- The yaml package enables Go programs to comfortably encode and decode YAML
- values. It was developed within [Canonical](https://www.canonical.com) as
- part of the [juju](https://juju.ubuntu.com) project, and is based on a
- pure Go port of the well-known [libyaml](http://pyyaml.org/wiki/LibYAML)
- C library to parse and generate YAML data quickly and reliably.
-
- Compatibility
- -------------
-
- The yaml package supports most of YAML 1.2, but preserves some behavior
- from 1.1 for backwards compatibility.
-
- Specifically, as of v3 of the yaml package:
-
- - YAML 1.1 bools (_yes/no, on/off_) are supported as long as they are being
- decoded into a typed bool value. Otherwise they behave as a string. Booleans
- in YAML 1.2 are _true/false_ only.
- - Octals encode and decode as _0777_ per YAML 1.1, rather than _0o777_
- as specified in YAML 1.2, because most parsers still use the old format.
- Octals in the _0o777_ format are supported though, so new files work.
- - Does not support base-60 floats. These are gone from YAML 1.2, and were
- actually never supported by this package as it's clearly a poor choice.
-
- and offers backwards
- compatibility with YAML 1.1 in some cases.
- 1.2, including support for
- anchors, tags, map merging, etc. Multi-document unmarshalling is not yet
- implemented, and base-60 floats from YAML 1.1 are purposefully not
- supported since they're a poor design and are gone in YAML 1.2.
-
- Installation and usage
- ----------------------
-
- The import path for the package is *gopkg.in/yaml.v3*.
-
- To install it, run:
-
- go get gopkg.in/yaml.v3
-
- API documentation
- -----------------
-
- If opened in a browser, the import path itself leads to the API documentation:
-
- - [https://gopkg.in/yaml.v3](https://gopkg.in/yaml.v3)
-
- API stability
- -------------
-
- The package API for yaml v3 will remain stable as described in [gopkg.in](https://gopkg.in).
-
-
- License
- -------
-
- The yaml package is licensed under the MIT and Apache License 2.0 licenses.
- Please see the LICENSE file for details.
-
-
- Example
- -------
-
- ```Go
- package main
-
- import (
- "fmt"
- "log"
-
- "gopkg.in/yaml.v3"
- )
-
- var data = `
- a: Easy!
- b:
- c: 2
- d: [3, 4]
- `
-
- // Note: struct fields must be public in order for unmarshal to
- // correctly populate the data.
- type T struct {
- A string
- B struct {
- RenamedC int `yaml:"c"`
- D []int `yaml:",flow"`
- }
- }
-
- func main() {
- t := T{}
-
- err := yaml.Unmarshal([]byte(data), &t)
- if err != nil {
- log.Fatalf("error: %v", err)
- }
- fmt.Printf("--- t:\n%v\n\n", t)
-
- d, err := yaml.Marshal(&t)
- if err != nil {
- log.Fatalf("error: %v", err)
- }
- fmt.Printf("--- t dump:\n%s\n\n", string(d))
-
- m := make(map[interface{}]interface{})
-
- err = yaml.Unmarshal([]byte(data), &m)
- if err != nil {
- log.Fatalf("error: %v", err)
- }
- fmt.Printf("--- m:\n%v\n\n", m)
-
- d, err = yaml.Marshal(&m)
- if err != nil {
- log.Fatalf("error: %v", err)
- }
- fmt.Printf("--- m dump:\n%s\n\n", string(d))
- }
- ```
-
- This example will generate the following output:
-
- ```
- --- t:
- {Easy! {2 [3 4]}}
-
- --- t dump:
- a: Easy!
- b:
- c: 2
- d: [3, 4]
-
-
- --- m:
- map[a:Easy! b:map[c:2 d:[3 4]]]
-
- --- m dump:
- a: Easy!
- b:
- c: 2
- d:
- - 3
- - 4
- ```
-
|