Categorygithub.com/oasdiff/yaml3
modulepackage
0.0.0-20241214160948-977117996672
Repository: https://github.com/oasdiff/yaml3.git
Documentation: pkg.go.dev

# README

YAML support for the Go language

Fork

This fork is an improved version of the go-yaml/yaml package, designed to include line and column location information for YAML elements during unmarshalling.

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 1.2, 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:

API stability

The package API for yaml v3 will remain stable as described in 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

package main

import (
        "fmt"
        "log"

        "oasdiff/yaml"
)

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

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.

# Constants

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# Structs

A Decoder reads and decodes YAML values from an input stream.
An Encoder writes YAML values to an output stream.
Node represents an element in the YAML document hierarchy.
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

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