"Function" Statement and Function Call

This section describes how to define and invoke a function procedure. Assigning a value to the procedure name in the function procedure sets the return value.

A "Function" statement defines a function procedure with the following syntax:

   Function function_name(argument_list)
      function_name = return_value
   End Function

where "function_name" is the name of the function, "argument_list" a list of variables used to pass data into and/or out of the function, and "return_value" is the value to be returned explicitly to the invoking statements.

Of course, "argument_list" is optional.

Assigning the return value to the function name is also optional. If not given, a default value will be returned to the invoking statements. But this is not recommended.

Invoking a function procedure is simple, no need of any special statements. Just use the function name with an argument list in any expression:

   ... function_name(argument_list) ...

This will cause the system to:

If you want terminate a function procedure early, you can use the "Exit" statement:

   Exit Function

Table of Contents

 About This Book

 Introduction of VBScript - Visual Basic Scripting Edition

 Variant Data Type, Subtypes, and Literals

 Arithmetic Operations

 Numeric Comparison Operations and Logical Operations

 String Operations - Concatenation and Comparison

 Variable Declaration and Assignment Statement

 Expression and Order of Operation Precedence

 Statement Syntax and Statement Types

 Array Data Type and Related Statements

 Array References and Array Assignment Statements

 Conditional Statements - "If ... Then" and "Select Case"

 Loop Statements - "For", "While", and "Do"

"Function" and "Sub" Procedures

 What Is a Procedure?

"Function" Statement and Function Call

 Function Procedure Example

 "Sub" Statement and Subroutine Call

 Sub (Subroutine) Procedure Example

 Passing Arguments to Procedures

 Example - Passing Arguments by Reference

 Example - Passing Arguments by Value

 Passing Arrays as Arguments

 Variable Scope in Procedures

 Example - Variable Scope in Procedures

 Built-in Functions

 Inspecting Variables Received in Procedures

 Error Handling Flag and the "Err" Object

 Regular Expression Pattern Match and Replacement

 scrrun.dll - Scripting Runtime DLL Library

 Creating Your Own Classes

 IE Web Browser Supporting VBScript

 IIS ASP Server Supporting VBScript

 WSH (Windows Script Host)


 Full Version in PDF/EPUB