A cross platform YAML 1.2 parser and renderer for Haxe.

cross, utility
haxelib install yaml 2.0.1



A cross platform YAML 1.2 parser and renderer for Haxe 3+. Ported from the feature rich js-yaml. Currently supports JavaScript, Flash (as3), CPP and Neko 2.0+.


From haxelib:

haxelib install yaml

Or the latest directly from GitHub

haxelib git yaml https://github.com/mikestead/hx-yaml.git src



invoice: 34843
date   : 2001-01-23
bill_to: &id001
  given  : Chris
  family : Dumars
    lines: |
      458 Walkman Dr.
      Suite #292
    city    : Royal Oak
    state   : MI
    postal  : 48046
ship_to: *id001
tax  : 251.42
457: true
total: 4443.52
comments: >
  Late afternoon is best.
  Backup contact is Nancy
  Billsmer @ 338-4338.


import yaml.Yaml;
import yaml.Parser;
import yaml.Renderer;
import yaml.util.ObjectMap;

class Example
	static function main()

	static function parsingExample()
		#if sys
		// Load and parse our invoice document using yaml.util.ObjectMap for key => value containers.
		// Using this default option allows for complex key types and a slightly nicer api to 
		// iterate keys/values. 
		// Equivalent to Yaml.read("invoice.yaml", Parser.options().useMaps());
		var data:AnyObjectMap = Yaml.read("invoice.yaml"); 

		trace(data.get("tax")); // 251.42
		trace(data.get(457)); // true
		// Load and parse the same document this time using dynamic objects for key => value containers.
		// This option will stringify all keys but is useful for mapping to typedefs.
		var data = Yaml.read("invoice.yaml", Parser.options().useObjects());
		trace(data.invoice); // 3483
		trace(data.ship_to.given); // Chris
		trace(Reflect.field(data, "457")); // true
		// If you already have the yaml document in string form you can parse it directly
		var data = Yaml.parse("key: value");
		trace(data.get("key")); // value

	static function renderingExample()
		var receipt = {assistant:"Chris", items:[{rice:2.34}, {milk:1.22}]};

		// Render an object tree as a yaml document.
		var document = Yaml.render(receipt);

		//  assistant: Chris
		//  items:
		//      - rice: 2.34
		//      - milk: 1.22

		#if sys
		// This time write that same document to disk and adjust the flow level giving 
		// a more compact result.
		Yaml.write("receipt.yaml", receipt, Renderer.options().setFlowLevel(1));


assistant: Chris
items: [{rice: 2.34}, {milk: 1.22}]



// Parse a single yaml document into object form
yaml.Yaml.parse(document:String, ?options:ParserOptions):Dynamic

// (sys only) Read a single yaml document from disk and parse it into object form
yaml.Yaml.read(filePath:String, ?options:ParserOptions):Dynamic

	- strict:Bool     - Parser will throw errors instead of tracing warnings. Default `false`.
    - validate:Bool   - Perform validation checks while parsing. Default is `true`.
    - schema:Schema   - The schema to use. Default is `yaml.schema.DefaultSchema`.
    - maps:Boolean    - True when using ObjectMaps, false when using Dynamic objects.


// Render a yaml object graph as a yaml document
yaml.Yaml.render(data:Dynamic, ?options:RenderOptions):String

// (sys only) Render a yaml object graph as a yaml document and write it to disk
yaml.Yaml.write(filePath:String, data:Dynamic, ?options:RenderOptions):Void

	- indent:Int        - The space indentation to use. Default `2`.
	- flowLevel:Int     - The level of nesting, when to switch from block to flow 
							style for collections. -1 means block style everywhere. Default `-1`.
	- styles:StringMap  - "tag" => "style" map. Each tag may have its own set of styles.
	- schema:Schema     - The schema to use. Default is `yaml.schema.DefaultSchema`.
Rendering Styles
  "canonical"   => "~"

  "binary"      => "0b1", "0b101010", "0b1110001111010"
  "octal"       => "01", "052", "016172"
  "decimal"     => "1", "42", "7290"
  "hexadecimal" => "0x1", "0x2A", "0x1C7A"

!!null, !!bool, !!float
  "lowercase"   => "null", "true", "false", ".nan", '.inf'
  "uppercase"   => "NULL", "TRUE", "FALSE", ".NAN", '.INF'
  "camelcase"   => "Null", "True", "False", ".NaN", '.Inf'

By default, !!int uses decimal, and !!null, !!bool, !!float use lowercase.

Supported YAML types

The list of standard YAML tags and corresponding Haxe types. See also YAML types.

!!null ''                   # null
!!bool 'yes'                # Bool
!!int '3...'                # Int
!!float '3.14...'           # Float
!!binary '...base64...'     # haxe.Binary
!!timestamp 'YYYY-...'      # Date
!!omap [ ... ]              # Array of yaml.util.ObjectMap
!!pairs [ ... ]             # Array of Array pairs
!!set { ... }               # yaml.util.ObjectMap of keys with null values
!!str '...'                 # String
!!seq [ ... ]               # Array
!!map { ... }               # yaml.util.ObjectMap

When parsing into maps, yaml.util.ObjectMap is used. Under Haxe 3.0 haxe.ds.ObjectMap would be used but it doesn't support primitive keys on all targets and we need a map which can contain a mixture of key types.


  • Under CPP and Neko UTC date translation is not yet possible so dates will be represented in local time instead.
  • Requires Neko 2.0+ when used under the Neko runtime due to its support for Unicode based regular expressions.
  • CPP support requires Haxe 3.1.2+ and hxcpp 3.0.2+