Abstract:
In an iconic programming computer system, the execution trail of objects is shown. Upon initiation by a user, the icons that have executed are highlighted so that the user, while debugging a program, can trace the path that the program has taken and identify which icons have executed.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to computer systems and more particularly to a method for showing the execution trail of objects in a graphical programming language. 
     BACKGROUND OF THE INVENTION 
     Graphical programming languages, like Hewlett-Packard&#39;s VEE, are iconic programming systems. Such a system is a “programming-less” environment where programming is performed by employing objects, or icons (i.e., graphical images of functions), together with connecting lines, to form a directed graph and create an iconic network which is representative of a software program. The iconic programming system may be used in a test and measurement system, where several different electronic instruments are connected to test a system or a device. Programming such a system requires instructions to cause the various instruments to perform desired functions in order to operate as a system. When an iconic programming system is used, each instrument will be represented by a graphical icon, and the connections between the instruments are represented by lines between the icons. Programming functions, such as IF-THEN-ELSE statements and FOR loops, can also be represented by icons. By combining programming icons with instrument icons, a user can create an iconic network related to the operation of the instruments. 
     Such iconic networks are often large and/or complicated. Debugging these networks is tedious and fraught with pitfalls. Often the user cannot be sure which icons have already executed and which paths the program took. There is a need in the art then for a system that will provide a way for a programmer in an iconic programming system to trace the path a program has taken and to identify which icons have executed while debugging the program. 
     Various features and components of an iconic programming system are disclosed in U.S. Pat. No. 5,325,481 for METHOD FOR CREATING DYNAMIC USER PANELS IN AN ICONIC PROGRAMMING SYSTEM of Hunt and U.S. Pat. No. 5,261,043 for PROCESSING METHOD FOR AN ICONIC PROGRAMMING SYSTEM of Beethe, each of which is hereby specifically incorporated by reference for all that is disclosed therein. 
     SUMMARY OF THE INVENTION 
     The present invention provides a method for showing the execution trail of objects in a graphical programming language. Upon initiation by the user, the method highlights objects that have executed so that, while debugging a program, the user can trace the path a program has taken and identify which icons have executed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a block diagram of a computer system incorporating the present invention. 
         FIG. 2  shows a representative iconic network. 
         FIG. 3  shows a flowchart of the method for showing the execution trail of icons according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIG. 1  shows a block diagram of a computer system  100  incorporating the present invention. A processing unit  110  is connected to system bus  105 . The system bus  105  facilitates communications between the processing unit  110  and memory  120 , a data storage disk  130  and an input/output interface device  140 . The memory stores the software of the present invention as well as all data collected and generated by the present invention. An first area  122  within the memory  120  is set aside for storage of the present method which is described more fully below. A second area  124  within the memory  120  contains the user-defined iconic network. The input/output interface device  140  controls data communications between the bus  105  and a display  142 , a keyboard  144  and a point-and-click input device  146 . An instrument bus  150  is used to allow the iconic programming system to communicate with test instruments. In a preferred embodiment, the instrument bus  150  is an IEEE-488 bus. 
       FIG. 2  shows a representative iconic network. Display screen  200  contains a first numeric input icon  210  which is used to define a start point and a second numeric input icon  212  which is used to define the number of points to be displayed in a view screen  220 . The start point is sent over connecting line  201  to view screen  220  to set the starting point of the view screen which displays logic activity of a device under test (not shown), or DUT. The number of points to be displayed are sent over connecting line  202  to a count icon  214 . The count icon  214  will count from zero to the number of points defined in icon  212 . Each time the count icon  214  increments the count value by one, a signal will be sent over connecting line  203  to the view screen  220  which in turn updates the logic activity signal with an additional data point. 
     Each time the view screen  220  updates, a signal is sent over connecting line  204  to IF-THEN-ELSE function icon  230 . If A is either equal to zero or less than 1, then function icon B 1  is executed; else, if A equals 1, then function icon B 2  is executed. 
     Each icon in  FIG. 2  has a frame that is highlightable; that is, the lines that comprise the rectangular box that frames each icon can be set to be a predetermined color which in effect highlights the icon on the display screen. 
       FIG. 3  shows a flow diagram of the present invention. Block  310  sets the trace mode of the present method to “on.” In a preferred embodiment, this is accomplished by the end user who would click the mouse on a toolbar button to enable the present method. The “for loop” indicated by block  320  then operates to examine each icon in the display screen to determine if the icon was executed (decisional block  330 ). If the icon has not been executed, no action is taken. If decisional block  330  determines that the icon has been executed, control is passed to block  340  to set a TRACE_FLAG to “on.” 
     After each icon is processed, block  350  examines each icon that has had its TRACE_FLAG set to on; for those icons that have TRACE_FLAG set equal to on, block  360  highlights the frame. 
     Referring back to  FIG. 2  for illustrative purposes, as flow moves through each icon, the TRACE_FLAG for each icon that is executed is set equal to “on.” For looping functions (e.g., icons  214  and  230 ), the present method will set highlight the last iteration of the of the loop. So, for example, if the “else” clause of the IF-THEN-ELSE function icon  230  executed during the last iteration of the loop, then function B 2   234  will be highlighted, and not function B 1   232 . 
     While the present invention has been illustrated and described in connection with the preferred embodiments, it is not to be limited to the particular structures shown. It should be understood by those skilled in the art that various changes and modifications may be made within the purview of the appended claims without departing from the true scope and spirit of the invention in its broader aspects.