package
0.0.0-20240819164739-f47aed85de5a
Repository: https://github.com/unix-world/smartgo.git
Documentation: pkg.go.dev

# README

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 as part of the juju project, and is based on a pure Go port of the well-known libyaml C library to parse and generate YAML data quickly and reliably.

Compatibility

The yaml package supports most of YAML 1.1 and 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.v2.

To install it, run:

go get gopkg.in/yaml.v2

API documentation

If opened in a browser, the import path itself leads to the API documentation:

API stability

The package API for yaml v2 will remain stable as described in gopkg.in.

License

The yaml package is licensed under the Apache License 2.0. Please see the LICENSE file for details.

Example

package main

import (
        "fmt"
        "log"

        "gopkg.in/yaml.v2"
)

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

# Functions

FutureLineWrap globally disables line wrapping when encoding long strings.
Marshal serializes the value provided into a YAML document.
NewDecoder returns a new decoder that reads from r.
NewEncoder returns a new encoder that writes to w.
Unmarshal decodes the first document found within the in byte slice and assigns decoded values into the out value.
UnmarshalStrict is like Unmarshal except that any fields that are found in the data that do not have corresponding struct members, or mapping keys that are duplicates, will result in an error.

# Structs

A Decoder reads and decodes YAML values from an input stream.
An Encoder writes YAML values to an output stream.
MapItem is an item in a MapSlice.
A TypeError is returned by Unmarshal when one or more fields in the YAML document cannot be properly decoded into the requested types.

# Interfaces

IsZeroer is used to check whether an object is zero to determine whether it should be omitted when marshaling with the omitempty flag.
The Marshaler interface may be implemented by types to customize their behavior when being marshaled into a YAML document.
The Unmarshaler interface may be implemented by types to customize their behavior when being unmarshaled from a YAML document.

# Type aliases

MapSlice encodes and decodes as a YAML map.