(PECL yaml >= 0.5.0)
yaml_emit — Returns the YAML representation of a value
$data
   [, int $encoding = YAML_ANY_ENCODING
   [, int $linebreak = YAML_ANY_BREAK
   [, array $callbacks
  ]]] )
   Generate a YAML representation of the provided data.
  
data
       The data being encoded. Can be any type except
       a resource.
      
encoding
       Output character encoding chosen from
       YAML_ANY_ENCODING,
       YAML_UTF8_ENCODING,
       YAML_UTF16LE_ENCODING,
       YAML_UTF16BE_ENCODING.
      
linebreak
       Output linebreak style chosen from
       YAML_ANY_BREAK,
       YAML_CR_BREAK,
       YAML_LN_BREAK,
       YAML_CRLN_BREAK.
      
callbacksContent handlers for emitting YAML nodes. Associative array of classname => callable mappings. See emit callbacks for more details.
Returns a YAML encoded string on success.
| Version | Description | 
|---|---|
| 1.1.0 | The callbacksparameter was added. | 
Example #1 yaml_emit() example
<?php
$addr = array(
    "given" => "Chris",
    "family"=> "Dumars",
    "address"=> array(
        "lines"=> "458 Walkman Dr.
        Suite #292",
        "city"=> "Royal Oak",
        "state"=> "MI",
        "postal"=> 48046,
      ),
  );
$invoice = array (
    "invoice"=> 34843,
    "date"=> 980208000,
    "bill-to"=> $addr,
    "ship-to"=> $addr,
    "product"=> array(
        array(
            "sku"=> "BL394D",
            "quantity"=> 4,
            "description"=> "Basketball",
            "price"=> 450,
          ),
        array(
            "sku"=> "BL4438H",
            "quantity"=> 1,
            "description"=> "Super Hoop",
            "price"=> 2392,
          ),
      ),
    "tax"=> 251.42,
    "total"=> 4443.52,
    "comments"=> "Late afternoon is best. Backup contact is Nancy Billsmer @ 338-4338.",
  );
var_dump(yaml_emit($invoice));
?>
The above example will output something similar to:
string(628) "---
invoice: 34843
date: 980208000
bill-to:
  given: Chris
  family: Dumars
  address:
    lines: |-
      458 Walkman Dr.
              Suite #292
    city: Royal Oak
    state: MI
    postal: 48046
ship-to:
  given: Chris
  family: Dumars
  address:
    lines: |-
      458 Walkman Dr.
              Suite #292
    city: Royal Oak
    state: MI
    postal: 48046
product:
- sku: BL394D
  quantity: 4
  description: Basketball
  price: 450
- sku: BL4438H
  quantity: 1
  description: Super Hoop
  price: 2392
tax: 251.420000
total: 4443.520000
comments: Late afternoon is best. Backup contact is Nancy Billsmer @ 338-4338.
...
"