Part II. Language Reference

Table of Contents

1. Basic syntax

Escaping from HTML

Instruction separation

Comments

2. Types

Introduction

Booleans

Syntax

Converting to boolean

Integers

Syntax

Integer overflow

Converting to integer

Floating point numbers

Converting to float

Strings

Syntax

Useful functions and operators

Converting to string

String conversion to numbers

Arrays

Syntax

Useful functions

Array do's and don'ts

Converting to array

Examples

Objects

Object Initialization

Converting to object

Resource

Converting to resource

Freeing resources

NULL

Syntax

Pseudo-types used in this documentation

mixed

number

callback

Type Juggling

Type Casting

3. Variables

Basics

Predefined variables

Variable scope

The global keyword

Using static variables

References with global and static variables

Variable variables

Variables from outside PHP

HTML Forms (GET and POST)

HTTP Cookies

Dots in incoming variable names

Determining variable types

4. Constants

Syntax

Predefined constants

5. Expressions

6. Operators

Operator Precedence

Arithmetic Operators

Assignment Operators

Bitwise Operators

Comparison Operators

Error Control Operators

Execution Operators

Incrementing/Decrementing Operators

Logical Operators

String Operators

Array Operators

7. Control Structures

if

else

elseif

Alternative syntax for control structures

while

do..while

for

foreach

break

continue

switch

declare

Ticks

return

require

include

require_once

include_once

8. Functions

User-defined functions

Function arguments

Making arguments be passed by reference

Default argument values

Variable-length argument lists

Returning values

Variable functions

Internal (built-in) functions

9. Classes and Objects

class

extends

Constructors

::

parent

Serializing objects - objects in sessions

The magic functions __sleep and __wakeup

References inside the constructor

Comparing objects in PHP 4

Comparing objects in PHP 5

10. References Explained

What References Are

What References Do

What References Are Not

Passing by Reference

Returning References

Unsetting References

Spotting References

global References

$this