Adobe 38043740 Developing Applications - Page 168

DEVELOPING COLDFUSION 9 APPLICATIONS 163 Building Blocks of ColdFusion Applications • If you use a name to pass an optional argument that is not declared in the function definition, the array index of the argument is the sum of the following: • The number of arguments defined with names in the function. • The position of the optional argument among the arguments passed in that do not have names defined in the function. However, using argument names in this manner is not good programming practice because you cannot ensure that you always use the same optional argument names when calling the function. To demonstrate these rules, define a simple function that displays the contents of its Arguments array and call the function with various argument combinations, as the following example shows: Argument #i#: #Arguments[i]# One Unnamed argument Two Unnamed arguments Three Unnamed arguments Arg1: Arg2: Arg1=8, Arg2=9: Arg2=6, Arg1=7 Arg1=8, Arg2=9, Arg3=10: Arg2=6, Arg3=99, Arg1=7 Note: Although you can use the Arguments scope as an array, the IsArray(Arguments) function always returns false and the cfdump tag displays the scope as a structure. Using the Arguments scope as a structure The following rule applies when referencing Arguments scope as a structure: • Use the argument names as structure keys. For example, if your function definition includes a Principal argument, reference the argument as Arguments.Principal. The following rules are also true, but avoid writing code that uses them. To ensure program clarity, only use the Arguments structure for arguments that you name in the function definition. Use the Arguments scope as an array for optional arguments that you do not declare in the function definition. Last updated 1/20/2012