Visual programming tool for developing software applications

Abstract

A visual programming method implemented on a computer having a display screen and an input device which a user employs to draw visual representations on the display screen, including the steps of defining and supporting by computer implemented steps a set of object classes including a linking object class; in response to input from the user, selecting a first object class; in response to the user using the input device to draw a first visual representation on the display screen, generating a source object, which is an instance of the first object class and having a first set of events associated therewith; in response to input from the user, selecting a second object class; and in response to the user using the input device to draw a second visual representation on the display screen, generating a destination object, which is an instance of the second object class; in response to input from the user, selecting the linking object class; and in response to the user using the input device to draw a third visual representation that connects the first and second visual representations, generating a linking object, which is an instance of the linking object class and has associated therewith a set of user selectable predefined behaviors, each of which is in the form of a set of commands that defines actions that occur to the destination object in response to an occurrence of one of the events of the first set of events.

Claims

What is claimed is:

1. A method for creating an application program, the method implemented on a computer system having a display screen and an input device, the input device controllable by a user to create visual representations on the display screen, the method/comprising:

A. defining and supporting a set of object classes, the set of object classes including a linking object class;

B. selecting, in response to input from the user, a first one of the object classes;

C. generating, in response to the user drawing a first visual representation on the display screen, a source object, the source object being an instance of the first object class and having a first set of associated default events and property settings;

D. selecting, in response to input from the user, a second one of the object classes;

E. generating, in response to the user drawing a second visual representation on the display screen, a destination object, the destination object being an instance of the second object class and having a second set of associated default events and property settings;

F. selecting, in response to input from the user, the linking object class;

G. generating, in response to the user drawing a third visual representation connecting the first and second visual representations, a linking object, the linking object being an instance of the linking object class and having a set of user selectable predefined behaviors used by the destination object, the predefined behaviors being responsive to at least one of the first set of associated events; and

H. displaying, in response to input from the user, the default events and property settings, of selected of the source, destination, and linking objects.

2. The method of claim 1 further comprising the step of:

I. providing a separate repository of predefined behaviors for various pair combinations of members of the set of object classes; and

wherein step G comprises:

G1. retrieving the set of user selectable predefined behaviors from the repository; and

G2. selecting one of the set of user selectable predefined behaviors as a default behavior for the linking object.

3. The method of claim 1 further comprising the step of:

J. defining and supporting a generic class, the generic class having a set of properties that are shared by each object class of the set of object classes.

4. The method of claim 1 wherein each of the behaviors are scripts defining actions involving the destination object in response to an occurrence of one of the events of the first set of events.

5. The method of claim 4 wherein the computer system includes an operating system and wherein one of the events is caused by the operating system.

6. The method of claim 4 wherein one of the events is caused by interaction with the user via the input device.

7. The method of claim 4 wherein one of the events is triggered programmatically.

8. The method of claim 4 wherein step G comprises the steps of:

G3. displaying a script editor;

G4. editing a first script, the first script defining a first relationship between the source object and the destination object; and

G5. associating the first script with the linking object.

9. The method as defined by claim 8 wherein step G further comprises the steps of:

G6. modifying the first script to be a second script defining a second relationship between the source object and the destination object; and

G7. associating the second script with the linking object.

10. The method as defined by claim 1 further including the step of:

K. providing a palette of visual objects;

L. utilizing the palette of visual objects for selecting the first one of the object classes.

11. An apparatus for visually creating an application program, the apparatus implemented on a computer system having a display screen and an input device, the input device controllable by a user to create visual representations on the display screen, the visual programming apparatus comprising:

means for defining and supporting a set of object classes, the set of object classes including a linking object class;

means for selecting, in response to input from the user, a first one of the object classes;

means for generating, in response to the user drawing a first visual representation on the display screen, a source object, the source object being an instance of the first object class and having a first set of associated default events and property settings;

means for selecting, in response to input from the user, a second one of the object classes;

means for generating, in response to the user drawing a second visual representation on the display screen, a destination object, the destination object being an instance of the second object class and having a second set of associated default events and property settings;

means for selecting, in response to input from the user, the linking object class;

means for generating, in response to the user drawing a third visual representation connecting the first and second visual representations, a linking object, the linking object being an instance of the linking object class and having a set of user selectable predefined behaviors used by the destination object, the predefined behaviors being responsive to at least one of the first set of associated events;

the linking object linking the source object and destination object; and

means for displaying and editing, in response to input from the user, the default events and property settings associated with selected of the source, destination, and linking objects.

12. The apparatus of claim 11 further comprising:

a separate repository of predefined behaviors for various pair combinations of members of the set of object classes; and

wherein the means for generating the linking object comprises:

means for retrieving the set of user selectable predefined behaviors from the repository; and

means for selecting one of the set of user selectable predefined behaviors as a default behavior for the linking object.

13. The apparatus of claim 11 further comprising means for defining and supporting a generic class, the generic class having a set of properties that are shared by each object class of the set of object classes.

14. The apparatus of claim 11 wherein each of the behaviors are scripts that define actions involving the destination object in response to an occurrence of one of the events of the first set of events.

15. The apparatus as defined by claim 14 wherein the means for generating the linking object comprises:

means for displaying a script editor;

means for editing a first script, the first script defining a first relationship between the source object and the destination object; and

means for associating the first script with the linking object.

16. The apparatus of claim 15 wherein means for generating a linking object comprises:

means for modifying the first script to be a second script defining a second relationship between the source object and the destination object; and

means for associating the second script with the linking object.

17. The apparatus of claim 11 further comprising:

a palette of visual objects;

means for utilizing the palette of visual objects for selecting the first one of the object classes.

18. A computer program product for use with a computer system having a display screen and an input device, the computer program product comprising:

a computer usable medium having computer readable program code thereon for visually programming an application program, the computer readable program code comprising:

program code for defining and supporting by computer implemented steps a set of object classes, the set of object classes including a linking object class;

program code for selecting, in response to input from the user, a first one of the object classes;

program code for generating, in response to the user drawing a first visual representation on the display screen, a source object, the source object being an instance of the first object class and having a first set of associated default events and property settings;

program code for selecting, in response to input from the user, a second one of the object classes;

program code for generating, in response to the user drawing a second visual representation on the display screen, a destination object, the destination object being an instance of the second object class and having a second set of each of the associated default events and property settings;

program code for selecting, in response to input from the user, the linking object class;

program code for generating, in response to the user drawing a third visual representation connecting the first and second visual representations, a linking object, the linking object being an instance of the linking object class and having a set of user selectable predefined behaviors for the destination object, the predefined behaviors being responsive to at least one of the first set of associated events

the linking object combining the source object and destination object to create the application program; and

program code for displaying and editing in response to input from the user, the default events and property settings associated with selected of the source, destination, and linking objects.

19. The computer program product of claim 18 further comprising:

program code for providing a separate repository of predefined behaviors for various pair combinations of members of the set of object classes;

wherein the program code for generating the linking object comprises:

program code for retrieving the set of user selectable predefined behaviors from the repository; and

program code for selecting one of the set of user selectable predefined behaviors as a default behavior for the linking object.

20. The computer program of claim 18 further comprising program code for defining and supporting by computer implemented steps a generic class, the generic class having a set of properties that are shared by each object class of the set of object classes.

21. The computer program product of claim 18 wherein each of the behaviors are scripts that define actions involving the destination object in response to an occurrence of one of the events of the first set of events.

22. The computer program product as defined by claim 21 wherein the program code for generating the linking object comprises:

program code for displaying a script editor;

program code for editing a first script, the first script defining a first relationship between the source object and the destination object; and

program code for associating the first script with the linking object.

23. The computer program product as defined by claim 22 wherein the program code for generating the linking object further comprises:

program code for modifying the first script to be a second script defining a second relationship between the source object and the destination object; and

program code for associating the second script with the linking object.

24. The computer program product as defined by claim 18 further including:

program code for providing a palette of visual objects; and

program code for utilizing the palette of visual objects for selecting the first one of the object classes.

Description

BACKGROUND OF THE INVENTION

The invention relates to a visual programming tool for developing software applications.

Historically, the development of software applications required trained and experienced software programmers. Under DOS with its character-based interface, programmers had to design data structures and write program code. This meant that extensive knowledge of the complexities of one or more programming languages was usually required. In recent years, however, with the introduction of windows-based operating systems and the move toward visual based user interfaces, significant progress has been made in developing visual programming tools which have made the task of designing and building applications much easier and more accessible to a wider range of people.

Visual programming focuses on the visual user interface. With visual programming tools, the user is provided with a palette of visual objects that represent commonly required functionality. The user develops an application simply by drawing objects on the screen and by moving those around using drag-and-drop techniques. The visual programming tool takes care of writing or adding the underlying code that is required to implement the functionality of the various objects that have been added to the screen. Thus, the process of writing large segments of code is taken over by the visual programming tool.

Nevertheless, even with prior visual programming tools, users have still had to write and add code to the application under design to complete it. Thus, even though these tools have made the process of designing and building applications much easier, they still have left standing significant barriers to users who are not experienced in programming or writing code.

SUMMARY OF THE INVENTION

In general, in one aspect the invention is a visual programming tool and method that includes a linking object, which is represented by a visual screen representation thereof, and a generic object. Associated with the linking object is an external file(s) containing predefined behaviors, i.e., command scripts which define actions that will be performed by the linking object on a destination object to which it is connected. The external file(s) contains behaviors for many different combinations of object types that are possible with the visual programming tool. When the user connects a linking object between a source object and a destination object, the programming tool presents the user with a list of the predefined behaviors from the external file that are appropriate for that particular combination of source and destination object.

The generic object is an abstract object from which most other objects are derived. Thus, it contains a set of properties and methods that are shared by most of the other objects in the tool. The generic object makes it possible for a running application (i.e., a designer tool) to bind with objects in an application under design and to access, manipulate, and/or modify the properties of the objects in the application under design.

In general, in another aspect, the invention is a visual programming method that is implemented on a computer having a display screen and an input device which a user employs to draw visual representations on the display screen. The method includes: the steps of defining and supporting by computer implemented steps a set of object classes, which includes within it a linking object class; in response to input from the user, selecting a first object classes; in response to the user using the input device to draw a first visual representation on the display screen, generating a source object, which is an instance of the first object class and has a first set of events associated therewith; in response to input from the user, selecting a second object classes; in response to the user using the input device to draw a second visual representation on the display screen, generating a destination object, which is an instance of the second object class; in response to input from the user, selecting the linking object class; and in response to the user using the input device to draw a third visual representation that connects the first and second visual representations, generating a linking object, which is an instance of the linking object class. The linking object has associated therewith a set of user selectable predefined behaviors, each of which is in the form of a set of commands that defines actions that occur to the destination object in response to an occurrence of one of the events of the first set of events.

Preferred embodiments include providing a separate repository of predefined behaviors for various pair combinations of members of said set of object classes. The step of generating the linking object includes retrieving the set of user selectable predefined behaviors from repository; and selecting one of the user selectable predefined behaviors as a default behavior for that linking object. The method also includes defining and supporting by computer implemented steps a generic class, which has a set of properties that are shared by each object class of the set of object classes.

The invention is a powerful and intuitive graphical interface that enables users to easily develop applications. The visual linking facility of ViP enables users to join various pieces of code together simply by adding to and manipulating graphical objects within a designer window. The invention shields the application developer from having to write any code or from having to learn the complexities of programming to build applications. The ViP development tools of the invention are very easy to use. The predefined behaviors that are provided with the linking objects anticipate the functionality that users will want to use in building applications for accessing, manipulating and displaying data and information.

The designer tools that can be constructed with the invention make it easy for a developer to easily impose a common design standard and appearance on the applications that are under design.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a block diagram of a typical system on which ViP is implemented;

FIG. 2 is a block diagram showing ViP data access;

FIG. 3 shows a typical designer window that is displayed by ViP;

FIG. 4 shows a Designer Toolbox as displayed by ViP;

FIG. 5 shows a Script Editor window;

FIG. 6A shows an application window with a visual representation of a command button object, a list box object, and a data object;

FIG. 6B shows a visual display that is generated during the running of the ViP application shown in FIG. 6A;

FIG. 7 shows an application with a command button and its right click menu;

FIG. 8 shows the right-click menu for a link object;

FIG. 9 shows a link setup menu for a link from a data column to a list box;

FIG. 10A shows a visual representation of a data object before a data connection has been defined for the object;

FIG. 10B shows a visual representation of a Connect to Data dialog box;

FIG. 11 shows a New Connection menu;

FIG. 12 shows an Add Columns menu;

FIG. 13 shows the Data Object options menu;

FIG. 14 shows an application under design;

FIG. 15 is a sample script for the Directory behavior;

FIG. 16 shows multiple links from two source objects;

FIG. 17 is a block diagram of the structure of a ViP application;

FIG. 18 is a sample script showing how to bind an object reference to an object;

FIG. 19 is a sample script showing how to bind a generic object reference to an object;

FIG. 20 illustrates using a generic object reference to access a currently selected object;

FIG. 21 is a designer tool script;

FIG. 22 is a sample designer tool layout;

FIG. 23 is an Init script for the designer tool illustrated in FIG. 22;

FIG. 24 is a script that is attached to the Print Class Name command button of the designer tool illustrate in FIG. 22;

FIG. 25 is a script that is attached to the Exit command button of the designer tool illustrated in FIG. 22; and

FIG. 26 is a dialogue box for the link tracer.

The following tables can be found in the specification:

Table 1 lists the properties that are common to most ViP objects;

Table 2 lists the events that are common to most ViP objects;

Table 3 lists the methods that are common to most ViP objects;

Table 4 lists the special methods of the Clipboard Object;

Table 5 shows the format of the string parameter to the Bind form of the SET statement;

Table 6 lists methods that return the names of objects in a design window;

Table 7 lists methods that get and set the selection state of an object; and

Table 8 lists methods that get and set the script of an object.

Attached to end of the specification are the following appendices:

Appendix 1 describes the AppWin class;

Appendix 2 describes the CommandButton class;

Appendix 3 describes the OptionButton class;

Appendix 4 describes the CheckBox class;

Appendix 5 describes the TextBox class;

Appendix 6 describes the ListBox class;

Appendix 7 describes the ComboBox class;

Appendix 8 describes the ScrollBar class;

Appendix 9 describes the TimerObject class;

Appendix 10 describes the Line class;

Appendix 11 describes the Rectangle class;

Appendix 12 describes the Ellipse class;

Appendix 13 describes the StaticText class;

Appendix 14 describes the GroupBox class;

Appendix 15 describes the Data class;

Appendix 16 describes the OLE class;

Appendix 17 describes the Chart class;

Appendix 18 describes the Link class;

Appendix 19 describes the ClipboardObject class;

Appendix 20 describes the Generic class;

Appendix 21 shows the contents of the VIPLINK.BHV file;

Appendix 22 describes the Class method;

Appendix 23 describes the DIM statement and its use;

Appendix 24 describes the SET statement and its use;

Appendix 25 describes the FindObject method;

Appendix 26 describes the FindSelectedObject method;

Appendix 27 describes the MostSelectedobject method;

Appendix 28 describes the FindLink Method;

Appendix 29 describes the GetSelectedState method;

Appendix 30 describes the SetSelectedState method;

Appendix 31 describes the GetScript method;

Appendix 32 describes the SetScript method;

Appendix 33 describes the DesignerNotify property;

Appendix 34 describes the Designer event;

Appendix 35 lists the predefined link behaviors;

Appendix 36 describes the functionality of the predefined link behaviors listed in Appendix 35;

Appendix 37 describes the generic properties of the generic object; and

Appendix 38 describes the generic methods of the generic object.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

ARCHITECTURAL OVERVIEW

The invention is a visual programming tool (referred to hereinafter as ViP.TM.) that enables users to rapidly develop applications (referred to hereinafter as ViP applications). Referring to FIG. 1, ViP runs on a 80386 or 80486-based computer 51 that uses Microsoft.RTM. Windows.TM. 3.1 or higher. The computer includes a 12 MB random access memory and 100 MB hard drive. Attached to the computer is a VGA or higher resolution monitor 53, a mouse 55 with right and left click buttons, and a keyboard 57. Computer 51 is connected to a network 59 (e.g. Novell.RTM. Netware 3.86 version 3.11) to which are connected various database servers and files (not shown). With ViP running on the computer, the user can use the pointing device (e.g. the mouse) to simply draw and connect objects on the computer screen and thereby build application programs which access, manipulate, process, and display data and other information.

The ViP application which a user constructs using the visual programming tools of ViP is a structured collection of objects. A set of events is associated with each of these objects. ViP links, which the user draws, and scripts, which the user writes, define responses to these events. When an object event occurs, the ViP application responds by executing the specified event procedure.

Objects

A ViP application consists of one or more application windows, each of which may contain a variety of objects, including Windows controls, graphic objects (such as ellipses and rectangles), data objects, charts, OLE objects, and others.

Object classes

Classes are custom LotusScript.TM. data types. Note that LotusScript is a BASIC programming language that was designed by and is commercially available from Lotus Development Corporation of Cambridge, Mass. (see, for example, LotusScript: Language Reference, Release 2). Each object in a ViP application is an instance of a product-defined class. There are 20 ViP object classes, which are described in greater detail below. Each class definition includes a set of properties, methods, and events.

Properties

Properties define the appearance and behavior of objects. Many object classes have properties defining visual attributes such as background color, size, and location. When the user creates an object, either by drawing it on an application window or in an event script, the object has default property values. While laying out the objects in an application, the user can use ViP Designer menus and dialog boxes to access the functionality of ViP which enables the user to reset property values. The user can also reset properties programmatically at run time.

Methods

Methods are subprograms (i.e., object-oriented functions) that the user can use in scripts and links to manipulate objects at run time. For example, the user can use a Move method to move an object or a PictureLoad method to load a picture in an application window, group box, command button, rectangle, or ellipse. A ExecuteQuery method executes the retrieval query defined for a data object.

Events

Based on its class, each object in an application can respond to a predefined set of events. Events initiate the execution of application procedures. Many events are user actions, such as clicking a command button or a check box (Click events). Other events are internal, such as the elapsing of a specified interval for a timer object (a Timer event) or the completion of a database operation initiated by a data object (an Execute event). Some events are notification that something is about to happen. Events may also be triggered programmatically.

Event procedures

Event procedures take two forms: event scripts that the user writes and visual ViP links that the user draws from one ViP object to another.

Event scripts

An event script is executed when the specified object event occurs. The user writes event scripts, using LotusScript and a ViP API (Application Programmer's Interface), which includes ViP object properties, ViP object methods, and ViP functions.

ViP links

ViP Links are used to define a relationship between two objects so that when some action is performed on one of the objects (the source object), the other object (the destination object) is affected. A link script, which is part of the link object, defines what happens to the destination object when the link executes. The ViP application includes a set of predefined scripts, called behaviors, that can be executed in a link. One of these behaviors is designated a default behavior, but the user can choose another behavior from the set. The set of behaviors is determined by which kinds of objects the user links together. The user can extend the behaviors of existing links as well as add entirely new behaviors to the links.

ViP links automate the process of generating many event procedures. By drawing a ViP link from a source object to a destination object, ViP automatically generates a script for that connection.

Modules

ViP compiles one binary module for each application window in an application. The event scripts and ViP links associated with an application window and the objects it contains, along with an optional Declarations script, make up each application window module. The application window Declarations script includes the variable declarations, type and class definitions, functions, and subroutines that the user wants to make available to all the event procedures in the module.

There is also one public module per application, in which the user can place the type and class definitions, variable declarations, functions, and subroutines that the user wants to make available to all the modules in the application.

Data access

Using a data object, a chart object, and a report designer, a ViP application can connect to, manipulate, chart data from, and generate reports on a variety of data sources.

Data Objects and Data Connections

Referring to FIG. 2, a data object 1 plays a central role in ViP applications. Data objects are used to retrieve, insert, modify, and delete data from data sources, and to provide input for charts and reports. Using a data object, the user can connect to a data source and add columns to the data object from a table in the data source. A data object Connection property identifies its connection to a data source. When the user defines a connection through a data object, ViP adds the name of the connection and its definition to a data connection registry 3 for the application. The definition identifies such information as a driver 5, a server 7, and a data source 9. Data source 9 can be a Notes database 11, a relational database 13, a database file 15, or a spreadsheet file 17. Using gateways 21, the user can also access legacy data 23 on mainframes and minis. ViP uses the Notes API 25 to access Notes databases and uses DataLens.RTM. and ODBC.TM. drivers 27 to access other data sources.

Having defined a connection, the user can use it throughout the application. In other words, the user can use its name to set the Connection property of data objects in any application window.

The user can set up a data object to permit users to perform insert, modify, and delete operations in the data source to which the data object is connected.

Charts and reports

The chart object is used to plot data from a data object. The data can be retrieved from a data source, input by users, or received by the data object via ViP links, scripts, or DDE links. A data object can provide input to multiple chart objects. A chart object, however, must receive data from a single data object.

The Report Designer can be used to perform a variety of calculations, group data, and lay out a tabular or free-form report based on data from a data object. The user can design one report per data object.

ViP application files

A ViP application may manipulate multiple files (database, spreadsheet, and even text files), but the application itself is a single file. This file contains a public module, one or more application window modules, and a data connection registry.

Designer Tools

Using the above-described objects and event procedures, the user can build designer tools. Designer tools are ViP applications that help the user to design other ViP applications. The designer tool is a running ViP application that accesses and modifies the objects of another ViP application that is under design. For example, the user can create a designer tool that gives an object in an application that is under design a three-dimensional appearance with one click of a command button. The user can enhance the tool by adding features that lets the user specify the depth and background color of the object.

Designer tools can be constructed to help the user ensure consistency in the look of the ViP applications which the user designs. For instance, the user may have certain design conventions the user applies to every application. Perhaps the user always puts a command button that displays information about the application in the lower-left corner of the user's startup window. Using the objects describe herein, the user can create a tool that sizes the command button, assigns it the text "Info", and positions it at a standard position in the window.

THE VIP DEVELOPMENT ENVIRONMENT

The ViP development environment is a collection of tools for building applications. These tools include a ViP Desktop, a Designer window 2 (see FIG. 3) and a Designer Toolbox 20 (see FIG. 4), a Script Editor 40 (see FIG. 5), a Report Designer (not shown), and a Debugger (not shown).

Designer

When the user creates a new application or opens an application for design, ViP starts the Designer and displays the Designer window 2. Designer window 2 is used to design new applications. Referring to FIG. 3, the Designer window includes a title bar 4, a menu bar 6, a smarticons set 8, a client area 10 for displaying one or more application window icons 12, and a status bar 14. With the aid of a cursor 9 that is controlled of the mouse, the user can make various selections within the Designer window by clicking on the relevant icon.

The menu bar 4 permits the user to execute commands that save and close files, run and end applications, perform standard editing operations, and perform other tasks. SmartIcons set 8 lets the user quickly execute several of the menu commands. The client area displays an icon 12 for each window in the current application. Information about the current application window (i.e., the window that is open and in focus) is displayed in status bar 14 below client area 10.

If the user right-clicks on one of the icons, the ViP application displays a menu 16 through which the user can manipulate the application window. For example, menu 16 enables the user to: (1) open the window to modify the design of the application; (2) to rename the window; (3) to make a copy of the window and the design application associated therewith; and (4) to set the window as the startup window (i.e., the window which is run first when the application is run as part of multiple applications).

Designer Toolbox

Referring to FIG. 3, when the user double clicks on an application icon 12, ViP opens up an application window 60 (see FIG. 6) and displays the Designer Toolbox 20 (see FIG. 4) which provides the user with tools that will enable the user to draw objects on the application window. Designer Toolbox 20 presents a group of design tool that are available to the user to design an application. The tools include, a pointer 22, a linking tool 24, a data object tool 26, a static text tool 28, a rectangle tool 30, a command button tool 32, a check box tool 34, a combo box tool 36, a group box tool 38, a timer object tool 40, a chart object tool 42, a line tool 44, an ellipse tool 46, a text box tool 48, an option button tool 50, a list box tool 52, scroll bar tool 54, and an OLE object tool 56. With the exception of the pointer, which the user uses to select, move, and resize objects, each tool represents an object class.

The mouse is used to select tools from the Toolbox and draw objects on the application window. The user can also right-click a tool to display its name in a Designer status bar at the top of the screen.

Script Editor

Referring to FIG. 5, the Script Editor displays a Script Editor window 270 that can be used to modify link behaviors (described below) and write scripts. In the Script Editor, the user can move to and view scripts in all the modules (application window modules and the public module) in the application.

As noted, scripts are sets of LotusScript statements that invoke the properties and methods defined for ViP objects. Scripts are attached to an event so that the script executes in response to the event. The Script Editor enables the user to write scripts and attach them to a particular selectable event for the object. For example, the user could write a script to fill a list box with files from a particular directory when an option button is clicked. The user attaches the script to the Click event for the option button.

Each script is a function definition. The user enters the body of the function, and ViP provides a default function header (the keyword function and a function name) and adds the keywords end function at the end of the definition.

The function name takes the Objectname.sub.-- eventname %, where Objectname is the name of the object with which the script is associated and eventname is the name of the event to which the script is attached. The percent (%) sign after the event name indicates that the value returned by the function is an integer. The value is ignored. The function header is displayed in the Script Editor just above the area where the user enters scripts. The end function keywords are not displayed in the Script Editor.

Report Designer

The user opens the Report Designer from the Designer window Tools menu or directly from a data object (with a right-click menu). The Report Designer can be used to design and print detail and summary reports based on the data associated with a data object. The Report Designer presents a graphical environment in which the user can lay out tabular and free-form reports.

Debugger

From the Designer, the user can run applications with the Debugger. The Debugger can be used to help find errors in the logic of his applications. The Debugger window shows the script that is currently executing. The user can examine and modify variable values, view a list of the events that have occurred or are currently occurring, navigate through scripts in the application, and set breakpoints.

Building an application

This section introduces the major tasks involved in building an application. Keep in mind that the user does not need to complete the tasks in the order they are presented here. The ViP development environment enables the user to build, run, debug, and refine pieces of an application before dealing with the application as a whole.

Laying out application windows

An application window is a collection of objects that presents information and solicits user interactions with the application via the mouse and keyboard. Hence laying out an application window is also laying out a user interface.

When the ViP application is started, a ViP desktop displaying one or more applications icons is displayed on the screen. From the desktop, the user can run selected applications, open applications for design, or design new applications, which can then be added to the Desktop.

When the user opens a new application, the Designer window (see FIG. 3) is displayed which contains at least one application window icon. Through the Designer window, the user gains access to the functionality of the designer within ViP. The designer is used to create one or more application windows (FIG. 6). Double clicking on an application window icon invokes the Designer Toolbox (see FIG. 4) and a blank application window. The Designer Toolbox is used to draw objects in the application window.

Using the tools in the Designer Toolbox, the user draws objects in an application window and then draws links between objects or writes scripts to define the behavior of the objects. Each icon in the toolbox represents a tool for adding a different object to the application window. To obtain a description of the tool, the user right-clicks on the relevant icon and ViP displays a text description of that tool at the top of the Designer window.

Initially, the objects that the user creates, including application windows, have default property settings. ViP, through right-click menus that are associated with the objects, provides the user with the ability to modify the default property settings. At run time, the user can use link behaviors and event scripts to manipulate objects.

As shown in FIG. 7, using the tools of the Toolbox, a user has drawn a command button 100 in an application window 102. To access object properties for the command button, the user right-clicks the object and ViP displays a right-click menu 104 presenting the user with various menu selections. For example, right-click menu 104 for a command button includes setup, font, picture and script editor selections. Selecting one of the menu items causes ViP to display a dialog box through which the user can view and modify values for the relevant properties.

Placing each object within the designer window, causes ViP to automatically generate the underlying code which implements the functionality of the object. That is, ViP adds the relevant code to the application under design.

To generate code which links the source object and a destination object, the user uses the linking tool from the Toolbox. In the application window shown in FIG. 6, the user has created three objects, namely, a command button 110, a list box 112, and a data object 114. To link the list box to the data object, the user selects the linking tool from the Toolbox by clicking on the appropriate tool icon. Once this selection has been made, ViP indicates the type of tool that has been selected by modifying the display of the pointer 116 to indicate the selected tool. After having selected the linking tool, the user moves the pointer over to list box 112 and left-clicks on the list box to select it as the source object. While the mouse button is depressed, the user drags mouse pointer 116 over to the data object and releases the mouse button to select the data object as the destination object and to form a link. ViP visually represents the link between the two objects by a line connecting the two objects. If the link is formed between the list box as the source and the data object as the destination, the visible representation of the link when the link is selected will include a tag with the label "CellSetQueryFromListAndExecute", which identifies the default behavior of the link, i.e., the function which will be performed by the linking object. The Designer also generates an arrow that indicates the direction of the link (i.e., pointing to the destination object).

Note that ViP displays the tag identifying the default link behavior as the pointer moves over the object and prior to releasing the depressed button.

To change the behavior of the link, the user right-clicks on the link to invoke a right-click menu 120, such as is shown in FIG. 8. The menu has three options, namely, Setup, Lines & Color, and Script Editor. If the Setup option is selected, a Setup dialog box 130 is displayed (see FIG. 9). This dialog box gives the user the ability to select other behaviors that are displayed in a Behavior box 132 or to generate a custom behavior through the script editor option 134. (Note that the link setup box in FIG. 9 is for a link that is established from a data object to a list box.)

The data object 114 shown in FIG. 6 is added to the application window in the same way as the command button and the other objects. That is, the appropriate tool is selected from the Toolbox and the object is drawn in the application window. As noted above, the data object allows the user to connect to data sources, such as Notes, and retrieve, insert, update, and delete data.

When the data object is first added to an application window, it appears as shown in FIG. 10, without columns. Once the user has drawn a data object in the designer window, ViP allows the user to connect to a data source. This is done by right-clicking on the data object to invoke a right-click menu 140, also shown in FIG. 10. One of the options which the user can select is "Connect to Data". When this is selected, ViP displays a Connect to Data dialog box 145 (see FIG. 10B) on the screen. This dialog box includes a list 146 identifying the connections that have been established for other applications. The user can add to this list by selecting a "New" option button 147 or alternatively, if a connection already exists for the desired data base, by selecting that connection. If the user selects the "New" option, a "New Connection" dialogue box 150 (see FIG. 11) is displayed, enabling the user to select the driver, the server, and the database that is desired. The data object includes methods that are capable of carrying out the functions that are necessary to implement the selections. In this way, the ViP application can connect to Notes databases as well as to relational databases, database files, and spreadsheets.

Having established a connection between the data object and the data source, the user can specify which fields in the data source to work with. The fields map to columns in the data object. For example, the user can add columns to the data object by right-clicking on the data object to bring up the right-click menu, which offers the user an Add Columns option. If that option is selected, an Add Columns dialog box 170 (see FIG. 12) appears on the display, which list the source tables that are available through the established connection. The user selects a source table by double clicking on the appropriate entry in a source table list 172. In response to selecting a source table, ViP populates a source table fields list box 174 with a list of the available fields for the selected source table. An Add button 176 allows the user to add selected fields to the data object.

In the illustrated example, the user has selected the following fields:

State

Region

Product-Line

Total-Sales

The data object is provide with a default set of options. The user can alter the options by invoking the right-click menu and selecting the Setup function which will in turn give the user access to the data objects option menu shown in FIG. 13. The options that may be selected through this function are indicated in FIG. 13 and are self explanatory. One of the options of particular importance is the Autoquery option. If the user selects this option, thereby enabling it, as soon as the application is started the data source will automatically be queried and the results displayed in the visual representation of the data object on the display.

The user can add a link to specify the selection criteria for the data object. For example, this is accomplished by using the linking tool to draw a link 113 between the list box 112 and the Region column of data object 114, as shown in FIG. 6.

When the application is compiled and run, the data object queries the database and displays the relevant data in the data object representation on the display screen. When the user clicks on the command button, list 112 fills up with a list of the regions that are represented in the data object (see FIG. 6B).

To perform a query, the user simply clicks on one of the items listed in the list box and the data object updates the displayed data showing only the data which satisfies the selected criteria. For example, again referring to FIG. 6B, if the user selects "West" as the region listed in the list box, the data object will query the source table and display only the data records that have "West" in their Region column.

After the user has connected a data object to a data source and has added columns, the user can use the data object to supply input for charts and a report. The chart object provides access to the functionality of another external chart preparation application program, e.g. Lotus Chart.TM..

The user can also use OLE objects to link to or embed data from other Windows applications. For example, the user can use an OLE object to embed and play a sound script or to link to a Lotus 1-2-3.TM. worksheet (Lotus 1-2-3 is a spreadsheet program that is commercially available from Lotus Corporation). If the user links to a worksheet, other users can run 1-2-3 and manipulate the worksheet from within the ViP application as well as receive updates to the worksheet from users working in other applications.

A variety of objects in the ViP application include DDE properties and methods which can be used to establish ViP objects as DDE clients or servers and to establish DDE conversations. That is, those objects can exchange data with other Windows applications. The data that can be sent or received can include individual text strings, lists of text strings, numeric values, bitmaps, and metafiles.

ViP also provides a number of features that the user can use to build documentation into the ViP application. For example, the user can use static text and text boxes to display messages. The user can provide other users with a command button to click to display such a message.

When the user presses F1, the ViP application generates an application window Help event. The ViP application can respond to this event by displaying a message. ViP also provides a function that the user can use to open a standard Windows Help file.

Using the Script Editor

The Script Editor enables the user to view, write, and modify scripts. It has standard editor features, such as cut, copy, paste, and find and replace. The user can also compile scripts from the Script Editor and return to the previous version of a script if the user decides to cancel any changes made to it.

Referring to FIG. 5, when editing an application, the user can move from one script in the application to another using the three drop-down list boxes 274, 276, and 278 at the top of the Script Editor window 270. Drop-down list box 274 specifies the modules in the current application; drop-down list box 276 specifies the objects in the selected module; and drop-down list box 276 specifies the events associated with the selected object.

In FIG. 5, a script is displayed in a script area 280 of the Script editor window for the APP.sub.-- EUROPE module, the CmdExit object, and the Click event. In this case, the script uses the ViP CloseAppWindow function to close the application window when the CmdExit command button is clicked.

After the user has selected a module, object, and event to which to attach a script, the instructions that are to be executed when the event occurs are typed into script area 280. The instructions are LotusScript language statements that invoke ViP API properties, methods, and functions.

After the script has been entered, the user can compile it to check for syntax errors. When checking for errors, ViP compiles only the current script and the Declarations script (if there is one) for the application window in which the current script residues. The Public module is compiled only once and then is loaded into memory. Unlike the Declarations script, it is not recompiled each time the user compiles a script.

When the user saves or runs an application from the Designer, ViP automatically compiles any application windows that need compiling, so the user need not compile scripts at design time.

The user can explicitly compile the scripts using the Script Editor Script menu or a Compile button 282 on the status bar of the Script Editor window. Also, by default, the Script Editor automatically compiles the current script when the user navigates to another object or event or exits the Script Editor. When ViP encounters a syntax error, it advises the user of the error and asks allows the user the option of either continuing or fixing the error.

VIP OBJECTS: AN OVERVIEW

Objects are the building blocks of a ViP application. Each object the user creates is an instance of a LotusScript custom data type called a class. A LotusScript class may be user-defined (the application developer defines the class in a script) or product-defined (the class definition is predefined and provided with the product). ViP designer objects are instances of product-defined classes. An application window, for example, is an instance of the AppWindow class; individual check boxes are instances of the CheckBox class; and data objects are instances of the Data class.

When the user creates an application window and draws an object on it, ViP declares a variable on the appropriate class for each object and binds the variable to the object. The user can do the same at run time in event scripts.

ViP provides 20 predefined LotusScript classes. As part of the definition for each class, ViP defines properties, methods, events, and link behaviors that apply to the class. The classes are summarized below and further details are presented in Appendices 1-20, attached.

ViP classes

ViP provides the following classes each of which is more fully documented in Appendices 1-20, attached hereto. Each of the following classes, except for the application window, the clipboard object, and the generic object, is represented by a corresponding tool in the toolbox.

Application window

An application window is an instance of an AppWin class. An application window is the highest-level container object in a ViP application. An application window contains a collection of objects that present information and solicit user interactions with the mouse and keyboard. (See Appendix 1).

Windows controls

ViP provides classes that define the following Windows controls:

Command Button

A command button is an instance of the CommandButton class. A command button lets users initiate an action with a click. (See Appendix 2).

Option Button

An option button is an instance of the OptionButton class. An option button lets users initiate an action with a click. When grouped, option buttons present users with mutually exclusive options; users may select only one option in the group. (See Appendix 3).

Check Box

A check box is an instance of the CheckBox class. A check box lets users initiate an action with a click. When grouped, check boxes present users with non-exclusive options; users may select any number of options in the group. (See Appendix 4).

Text Box

A text box is an instance of the TextBox class. A text box displays information or accepts textual input from the user. (See Appendix 5).

List Box

A list box is an instance of the ListBox class. A list box displays a list of items from which the user can select. (See Appendix 6).

Combo Box

A combo box is an instance of the ComboBox class. A combo box combines the functionality and attributes of a list box and a text box. The list box portion of a combo box displays a list of items from which the user can select. The text box portion of a combo box displays the selected item and can be defined to accept textual input from the user. (See Appendix 7).

Scroll Bar

A scroll bar is an instance of the ScrollBar class. A scroll bar represents an evenly-distributed range of numerical values from which the user can select by scrolling through the range. (See Appendix 8).

Timers

A timer is an instance of the TimerObject class. A timer functions in the background and is not visible to the user. The user can use a timer to initiate processing when a specified time interval has passed. (See Appendix 9).

Graphic objects

ViP provides classes that define the following graphic objects:

Line

A line is an instance of the Line class. The user can place an arrowhead at the beginning or end of the line. (See Appendix 10).

Rectangle

A rectangle is an instance of the rectangle class. A rectangle can have a border, label, or pattern. The user can place a picture in a rectangle. (See Appendix 11).

Ellipse

An ellipse is an instance of the Ellipse class. A circle is a special case of an ellipse. An ellipse can have a border, label, or pattern. The user can place a picture in an ellipse. (See Appendix 12).

Static Text

A static text object is an instance of the StaticText class. Static text is text that is uneditable at run time. The user can layer static text on top of other objects. (See Appendix 13).

Group Box

A group box is an instance of the Group class. A group box functions both as a graphic object and as a container object. A group box logically and visually groups a collection of objects, such as option buttons. (See Appendix 14).

Data object

A data object is an instance of the Data class. They are tabular representations of external data and play a central role in ViP applications. The user uses data objects to retrieve, insert, modify, and delete data from Notes databases and other data sources; to provide input for charts and reports; and to send native commands to Notes, relational servers, and ODBC drivers. (See Appendix 15).

OLE object

An OLE object is an instance of the OLE class. An OLE object embeds data from another Windows application or links to data in another Windows application. (See Appendix 16).

Chart object

A chart object is an instance of the Chart class. A chart is an object that graphically represents data from a data object to which the chart object is connected. (See Appendix 17).

Link

A link is an instance of the Link class. A link is a special object that relates two other objects (a source object and a destination object) when a source object event (called a cause) occurs. A link consists of a link behavior that is a predefined, but modifiable, LotusScript script. At design time, the user draws a link between the source object and the destination object. At run time, when the cause (i.e., a source object event) happens, ViP executes the link behavior (i.e., a script). At design time, a ViP link has graphical attributes. (See Appendices 18, 35 and 36).

Clipboard object

A Clipboard object is an instance of the ClipboardObject class. A Clipboard object is an temporary storage area that the user can use when copying or moving ViP objects, text, pictures, or DDE links in a script. ViP automatically makes one instance of this object available to each ViP application. (See Appendix 19).

Generic object

A generic object is a member of the Object class. The Object class is a virtual class. A generic object has no actual existence in its own right. Instead, in a script, the user can declare a variable to refer to an instance of the Object class. This variable is a generic object reference. The user can bind this generic object reference to objects of any other class. (See Appendix 20).

With some exceptions, the other object classes are derived from the generic class. Stated differently, the generic object possesses a set of properties and methods that are common to almost all of the other objects. This enables the user to design a designer tool application (see later description of designer tools) which can modify the properties and scripts of objects within an application that is under design without the user having to know the identity of the objects in the application that is under design or even the object classes of those objects. (See Appendices 37 and 38 for a description of the generic properties and methods.)

Each class definition, which is documented in Appendices 1-20, includes a definition of the structure of instances of the class and the definition of a set of properties, methods, and events that apply to the class.

Properties

Properties are attributes that identify a class and define the appearance and behavior of objects that are instances of a class. For example, the text box object has properties that determine its background color, font, height, and width, among others. When the user creates an object by drawing its representation in an application window (or designer frame), the object which is created has default values for its properties. For example, the default value for an application window BackColor property (background color) is WHITE; and the default value for a text box Multiline property is FALSE (i.e., users can only enter one line of text).

A property typically has the following characteristics. A property applies to both a design-time object and a run-time object. ViP saves the design-time value of a property with the object when the user leaves design mode and the design-time value of the property becomes the initial run-time value of the property. Also, the user can both retrieve and specify a value for the property at design time and run time.

Some properties apply to only one object class. Only text boxes, for example, have a Multiline property, which determines whether the user can enter multiple lines in the text box. Only data objects have a Connection property, which defines the connection to an external data source, such as a Notes or SQL Server database.

The Clipboard object is a unique ViP object and only has one property, the Text property. The class definition for most other ViP objects includes the common properties described in Table 1 below:

                  TABLE 1
    ______________________________________
                                Objects property
    Property     Description    applies to
    ______________________________________
    Name         Name of the object
                                All
    Description  Description of the
                                All
                 object
    Parent       Name of the object
                                All
                 that contains the
                 object
    Bottom, Top, Left,
                 Coordinates that
                                All
    Right, Height,
                 determine the size and
    Width, and Layer
                 position of the object
                 in its container
                 object (either an
                 application window or
                 a group box)
    TabIndex     Position of the object
                                All
                 in the tab order of
                 the application window
    Visible      Whether the object is
                                All
                 visible or invisible
                 at run time
    Enabled      Whether the object is
                                All
                 enabled or disabled at
                 run time
    BackColor    Background color of
                                All graphic
                 the object     objects except
                                line and static
                                text; all
                                Windows controls
                                except command
                                button and
                                scroll bar
    Transparent  Whether the object is
                                All graphic
                 transparent or opaque
                                objects, check
                                box, and option
                                button
    Cursor       Shape of the mouse
                                All except link
                 pointer when the user
                                and the timer
                 moves it over the
                                object
                 object at run time
    Text         Textual data   Application
                 associated with the
                                windows; all
                 object         graphic objects
                                except line; all
                                Windows controls
                                except scroll
                                bar; data
                                objects
    FontName, FontSize,
                 Characteristics of the
                                Many of the
    FontStyle, and
                 font of the textual
                                objects that
    ForeColor    data in the object
                                have textual
                                data
    Justify      Placement of the text
                                Many of the
                                objects that
                                have textual
                                data
    LineColor,   Object border and
                                All graphic
    LineStyle, and
                 attributes of lines
                                objects except
    LineWidth                   group box; text
                                box and list
                                box; links
                                (LineColor only)
    DDEClientData Type,
                 Role of the object in
                                Application
    DDEClientItem,
                 a DDE conversation
                                windows; all
    DDEClientMode,              graphic objects
    DDEClientServer,            except the group
    DDEClientStatus,            box; all Windows
    DDEClientTimeOut,           controls; data
    DDEClientTopic,             objects
    DDEServerActive,
    and DDEServerEnable
    ______________________________________

                  TABLE 2
    ______________________________________
    When this happens     This event is triggered
    ______________________________________
    The object is functioning as a DDE
                          DDEActivity
    server and the DDE conversation
    starts or stops.
    The object is functioning as a DDE
                          DDEServerPoke
    server and data from a DDE client
    application arrives.
    The object is functioning as a DDE
                          DDEActivity
    client and data being sent from a DDE
    server changes.
    The object is functioning as a DDE
                          DDEClientArriving
    client and data from a DDE server
    arrives.
    The DoEvent or DoEventArgs method
                          User
    (with User as the event) for the
    object box executes.
    ______________________________________

                  TABLE 3
    ______________________________________
                                Objects methods
    Methods      Description    apply to
    ______________________________________
    Class        Retrieve the class
                                All
                 name of the object.
    Position and Move
                 Reset the      All
                 coordinates of the
                 object.
    ClipboardCopy,
                 Copy data to and
                                All
    ClipboardPaste
                 from the Clipboard.
    DoEvent,     Execute a script
                                All
    DoEventArgs  associated with an
                 event for the
                 object.
    FindProperty,
                 Retrieve the names
                                All
    FindEvent, FindLink
                 of the properties,
                 events, and links
                 associated with the
                 object.
    GetScript,   Retrieve and   All
    SetScript    specify a script
                 for an object event
                 at design time.
    GetProperty, Retrieve and   All
    SetProperty  specify the values
                 of the properties
                 of the object.
    Repaint      Redraw the object.
                                All
    CursorCopy,  Change the cursor
                                All except the
    CursorLoad   associated with the
                                timer object
                 object.
    FontSelect   Present the Windows
                                All objects that
                 Font dialog box to
                                have the font
                 users to that they
                                properties
                 can change the font
                 of the textual data
                 in the object.
    DDEClientExecute,
                 Manage the DDE Application
    DDEClientPoke,
                 conversation of the
                                windows; all
    DDEClientRequest,
                 object.        graphic objects
    DDEUseData                  except the group
                                box; all Windows
                                controls; data
                                objects
    ______________________________________

                  TABLE 4
    ______________________________________
    Method         Description
    ______________________________________
    Empty          Remove all data from the Clipboard
    FormatAvailable
                   Retrieve the name of the data formats
                   for the data on the Clipboard
    ______________________________________

    ______________________________________
    '=====================================
    'Set the data source for a chart and draw the chart.
    '=====================================
    dim RetCode%, I%
    Dest.ChartSource = Src.Name
    for I = 1 to 24
       RetCode% = Dest.SetColumnUsage(I, DONTCHART)
    Next I
    RetCode% = Dest.DrawChart()
    ______________________________________