This is my first php program!

Preface
|
xiii
Ric McGredy
Thanks to my family for putting up with my absence, to Nat for inheriting the
project while in the midst of family expansion, and to my colleagues at Media Net
Link for all their help and support.
,ch00.14996 Page xiii Wednesday, March 13, 2002 11:42 AM

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,ch00.14996 Page xiv Wednesday, March 13, 2002 11:42 AM

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This is the Title of the Book, eMatter Edition
Copyright © 2002 O’Reilly & Associates, Inc. All rights reserved.
17
Chapter 2
CHAPTER 2
Language Basics
This chapter provides a whirlwind tour of the core PHP language, covering such
basic topics as data types, variables, operators, and flow control statements. PHP is
strongly influenced by other programming languages, such as Perl and C, so if you’ve
had experience with those languages, PHP should be easy to pick up. If PHP is one of
your first programming languages, don’t panic. We start with the basic units of a
PHP program and build up your knowledge from there.
Lexical Structure
The lexical structure of a programming language is the set of basic rules that governs
how you write programs in that language. It is the lowest-level syntax of the lan-
guage and specifies such things as what variable names look like, what characters are
used for comments, and how program statements are separated from each other.
Case Sensitivity
The names of user-defined classes and functions, as well as built-in constructs and
keywords such as
echo
,
while
,
class
, etc., are case-insensitive. Thus, these three lines
are equivalent:
echo("hello, world");
ECHO("hello, world");
EcHo("hello, world");
Variables, on the other hand, are case-sensitive. That is,
$name
,
$NAME
, and
$NaME
are
three different variables.