Chapter 3: Using Coldfusion Variables - MACROMEDIA COLDFUSION MX 61-DEVELOPING COLDFUSION MX Develop Manual

Macromedia ColdFusion variables are the most frequently used operands in ColdFusion
expressions. Variable values can be set and reset, and can be passed as attributes to CFML tags.
Variables can be passed as parameters to functions, and can replace most constants.
This chapter describes how to create and use ColdFusion variables. It includes the following
information:
•
How variables can represent different types of data
•
How the data types get converted
•
How variables exist in different scopes
•
How the scopes are used
•
How to use variables correctly
Contents
Creating variables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Variable characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Data types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Using periods in variable references . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Data type conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
About scopes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Ensuring variable existence. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Validating data types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Passing variables to custom tags and UDFs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Using ColdFusion Variables
CHAPTER 3
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