Perl Tutorials - Herong's Tutorial Examples - v6.01, by Dr. Herong Yang
Scalar Value Constructors
This section describes what is a scalar value constructor, a numeric literal or a string literal, and what are syntax rules on using scalar value constructors.
Scalar value constructors are used to construct scalar values. There are two types of scalar value constructors: numerical literals and string literals.
Numerical literals must follow these rules:
String literals must follow these rules:
Here are some examples to help you understand better what are good or bad scalar value constructors:
1; # ok 8.8; # ok 9.9.9; # bad, not a numeric literal 1e-1; # ok 1e+50; # ok 1.0d; # bad, no double floating point format allowed '3.14'; # ok 1a; # bad, not a numeric literal and not a string literal 'hello'; # ok 'dir \\home\\herong'; # ok 'Herong's Notes'; # bad, need a backslash substitution \' "Herong's Notes"; # ok 'Hello world!\n'; # ok, but \n is not a backslash substitution here
Table of Contents
►Data Types: Values and Variables
Variables - Scalar, Array and Hash
"undef" Value and Undefined Variables
Expressions, Operations and Simple Statements
Name Spaces and Perl Module Files
Hard References - Addresses of Memory Objects
Objects (or References) and Classes (or Packages)
Typeglob and Importing Identifiers from Other Packages
String Built-in Functions and Performance
File Handles and Data Input/Output
Open Directories and Read File Names
File System Functions and Operations
Socket Communication Over the Internet
XML::Simple Module - XML Parser and Generator
SOAP::Lite - SOAP Server-Client Communication Module
Perl Programs as IIS Server CGI Scripts
CGI (Common Gateway Interface)
XML-RPC - Remote Procedure Call with XML and HTTP
RPC::XML - Perl Implementation of XML-RPC
Integrating Perl with Apache Web Server
CGI.pm Module for Building Web Pages
LWP::UserAgent and Web Site Testing
Converting Perl Script to Executable Binary