PhpValue

assembly: Peachpie.Runtime.dll

PHP is a loosely typed language. It specifies the value of a variable not to be restricted to a single type. This is referred to as type ambiguity, type dynamicity, or is also known as mixed.

PeachPie defines struct PhpValue as the abstraction of PHP's mixed. This .NET type is used in case a type of value cannot be resolved in compile time. It applies to global variables in general, function parameters without a type hint, function return types without a type hint, class properties, and local variables.

Conversions

To PhpValue

Any .NET type can be converted to PhpValue. The following table lists the types and the corresponding conversion function.

.NET type	Conversion routine	Sample
bool	implicit cast	(PhpValue)true
int	implicit cast	(PhpValue)(-1)
long	implicit cast	(PhpValue)9876543210L
double	implicit cast	(PhpValue)123.456
string	implicit cast	(PhpValue)"Hello"
byte[]	implicit cast	(PhpValue)Encoding.UTF8.GetBytes("Hello")
PhpArray	implicit cast	(PhpValue)new PhpArray() PhpArray represents PHP's array object.
delegate	implicit cast	(PhpValue)new Func<int>(() => 123) In PHP, the delegate is treated as an instance of a callable class.
object	FromClass()	PhpValue.FromClass(new System.Object())

From PhpValue

A value can be converted to a standard .NET type using the following conversion routines. When applicable, the conversion respects the PHP semantic of the casting values.

.NET type	Conversion routine	Sample	Remarks
bool	implicit cast	(bool)value	-
ushort	explicit cast	(ushort)value	OverflowException, PHP notice
int	explicit cast	(int)value	OverflowException, PHP notice
uint	explicit cast	(uint)value	OverflowException, PHP notice
long	explicit cast	(long)value	PHP notice
double	explicit cast	(double)value	PHP notice
string	explicit cast	value.ToString()	byte[] is encoded using UTF-8
PhpNumber	explicit cast	(PhpNumber)value	InvalidCastException
PhpArray	explicit cast	(PhpArray)value	conversion to array according to PHP semantic
PhpAlias	EnsureAlias()	value.EnsureAlias()	-
Object	AsObject()	value.AsObject()	gets underlaying class instance, can be null.
Object	ToClr()	#c# value.ToClr()	boxes any underlaying value into System.Object, can be null.
T	Cast()	#c# value.Cast<MyClass>()	performs appropriate conversion of underlaying value into CLR type T.

Operators

The type defines arithmetic and comparison operators according to PHP semantics.

Operator	Sample	Remarks
==	val1 == val2	non-string equality
!=	val1 != val2	non-strict inequality
<	val1 < val2	comparison
~	~val1	bit negation
&	val1 & val2	bit and
|	val1 | val2	bit or
^	val1 ^ val2	bit xor
/	val1 / val2	division, operands are converted to number
*	val1 * val2	multiplication, operands are converted to number
[]	val[1]	accessing value item as array according to PHP semantic
StrictEquals	val1.StrictEquals(val2)	strict equality, PHP' ===
ToArray	val.ToArray()	conversion to array according to PHP semantic
AsArray	val.AsArray()	gets underlaying PhpArray or null
AsCallable	val.AsCallable()	gets IPhpCallable from PHP' callable which can be invoked, can be null

Visitor pattern

PhpValue type implements a visitor pattern so you can traverse through the underlying value structure. It is useful in the case of arrays or objects. It is also used for implementing serializers.

Method: PhpValue.Accept( PhpVariableVisitor visitor)

Sample:

class MyVisitor : PhpVariableVisitor {
    public override void AcceptNull() { } // PhpValue contains NULL!
}
value.Accept( new MyVisitor() ); // traverses through the value, arrays and objects

Note, the visitor implementation does not check for cycles in the underlying structure. Infinite recursion may occur when the underlying object or array contains a referenced value to itself.