Defining And Using Custom Functions; Defining Functions - MACROMEDIA COLDFUSION 5-DEVELOPING Develop Manual

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Defining and Using Custom Functions

You can define custom functions (also known as user-defined functions) and use
them in your application pages as you do standard ColdFusion functions. This
allows you to create a function for an algorithm or procedure that you use frequently,
and then use the function wherever you need the procedure. If you must change the
procedure, you change only one piece of code. You can use your function anywhere
that you can use a ColdFusion expression: in tag attributes, between # signs in
output, and in CFScript code.

Defining functions

You define functions using CFScript, in a manner similar to defining JavaScript
functions. The function must return a value. Functions can be recursive, that is, the
body of a function can call the function.
You can define a function in the following places:
Syntax Use the following syntax inside a
function functionName( [paramName1[, paramName2...]] )
{
}
functionName
paramName1...
The body of the function definition must consist of one or more valid CFScript
statements.
Chapter 13 Extending ColdFusion Pages with CFML Scripting
On the page where it is called (even after it is called, although this is not
recommended).
On a page that you include using a
executed before the function gets called. For example, you can define all your
application's functions on a single page and place a
pages that use the functions.
CFScript Statements
The name of the function. You cannot use the name of an standard ColdFusion
function name. You cannot use the same name for two different function
definitions. Function names cannot include periods.
Names of the parameters required by the function. The number of arguments
passed into the function must equal or exceed the number of parameters in the
function definition. If the calling page omits any of the required parameters,
ColdFusion generates a mismatched argument count error.
tag. The
cfinclude
tag to define a function:
cfscript
tag must be
cfinclude
tag at the top of
cfinclude