yaml

Support for parsing and rendering YAML documents.

http://github.com/snoyberg/yaml/

Version on this page:0.8.23.3
LTS Haskell 24.18:0.11.11.2@rev:2
Stackage Nightly 2025-11-04:0.11.11.2@rev:2
Latest on Hackage:0.11.11.2@rev:2

See all snapshots yaml appears in

BSD-3-Clause licensed by Michael Snoyman, Anton Ageev, Kirill Simonov
Maintained by Michael Snoyman
This version can be pinned in stack with:yaml-0.8.23.3@sha256:039fffb0b149900970b457f648d2ea686ced8ec6e8f4d51ab553880e75a718d5,5093

Module documentation for 0.8.23.3

yaml

Provides support for parsing and emitting Yaml documents.

This package includes the full libyaml C library version 0.1.7 by Kirill Simonov in the package so you don’t need to worry about any non-Haskell dependencies.

The package is broken down into two primary modules. Data.Yaml provides a high-level interface based around the JSON datatypes provided by the aeson package. Text.Libyaml provides a lower-level, streaming interface. For most users, Data.Yaml is recommended.

Examples

Usage examples can be found in the Data.Yaml documentation or in the examples directory.

Additional modules

  • Data.Yaml.Include supports adding !include directives to your YAML files.
  • Data.Yaml.Builder and Data.Yaml.Parser allow more fine-grained control of parsing an rendering, as opposed to just using the aeson typeclass and datatype system for parsing and rendering.
  • Data.Yaml.Aeson is currently a re-export of Data.Yaml to explicitly choose to use the aeson-compatible API.

Changes

0.8.23.3

  • Avoid over-escaping * #113

0.8.23.2

  • Update libyaml #110

0.8.23.1

  • Update CPP MIN_VERSION_* checks #109

0.8.23

  • Re-export the with helpers from aeson

0.8.22.1

  • Make numeric string detection slightly smarter so, e.g., . does not get quoted

0.8.22

  • Update to libyaml hosted on Github #105

0.8.21.2

  • Fix wrong file not found exception in Data.Yaml.Include with pre-1.2.3.0 directory #104

0.8.21.1

  • Add missing test files #102

0.8.21

  • Decode empty inputs as Null #101

0.8.20

  • Upgrade to libyaml 0.1.7

0.8.19.0

  • Add Data.Yaml.TH module

0.8.18.7

  • Add O_TRUNC when opening files

0.8.18.6

  • s/fdopen/_fdopen on Windows #96

0.8.18.5

  • Properly fix previous bug (fixes #94)

0.8.18.4

  • Remove file with non-ASCII name due to Stack/cabal-install/Hackage restrictions (see #92)

0.8.18.2

  • Handle non-ASCII filenames correctly on Windows #91

0.8.18.1

  • Improve prettyPrintParseException when context is empty #89

0.8.18

  • Switched yaml decode function for config file readers in Data.Yaml.Config to the one from Data.Yaml.Include that supports !include syntax.

0.8.17.2

  • Fix pretty-printing order of UnexpectedEvent’s fields (fixes #84) #85

0.8.17.1

  • Avoid bug in Cabal #83

0.8.17

  • loadYamlSettingsArgs

0.8.16.1

  • Slight doc improvement

0.8.16

Add env variable parsing. loadYamlSettings can read config values from the environment with Yaml that specifies an env var. The syntax is

var: _env:ENV_VAR:default

0.8.15.3

  • Give a warning when compiling with GHCJS

0.8.15.2

  • Canonicalise Monad instances #76

0.8.15.1

  • Compile with aeson below 0.7 #70

0.8.15

  • Parse Scientific directly, avoiding loss in precision. #68

0.8.14

  • Pretty print improvements for exceptions #67

0.8.13

  • Pretty module #66

0.8.12

  • Proper handling of String "+123" #64

0.8.11

  • Function to print prettier parse exceptions #59

0.8.10

Add the Data.Yaml.Include module