The Ring programming language version 1.7 book - Part 85 of 196

The Ring programming language version 1.7 book - Part 85 of 196

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  Ring Documentation, Release1.7 y: 20.000000 z: 30.000000 70.27 ringvm_give() function Using the ringvm_give() function we can redefine the behavior of the Give command Example: see "Name: " give name see "Hello " + name func ringvm_give see "Mahmoud" + nl return "Mahmoud" Output: Name: Mahmoud Hello Mahmoud 70.27. ringvm_give() function 812
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  CHAPTER SEVENTYONE THE TRACE LIBRARYAND THE INTERACTIVE DEBUGGER In this chapter we will learn about the Trace Library and the Interactive Debugger 71.1 Loading the Trace library To start using the Trace library, We must load it first! load "tracelib.ring" 71.2 Trace All Events The next example demonstrates the Trace library usage to trace all events. # Trace All Events trace(:AllEvents) see "Hello, world!" + nl see "Welcome" + nl see "How are you?" +nl mytest() new myclass { mymethod() } func mytest see "Message from mytest" + nl class myclass func mymethod see "Message from mymethod" + nl 71.3 Trace control flow between functions The next example demonstrates the Trace library usage to trace the control flow between functions. Trace(:Functions) test1() 813
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  Ring Documentation, Release1.7 func test1 see :test1 + nl test2() func test2 see :test2 + nl see test3() + nl func test3 see :test3 + nl return "test 3 output" 71.4 Pass Error The next example demonstrates the Trace library usage to pass an error! Trace(:PassError) test1() func test1 x = 10 see :test1 + nl test2() # Runtime Error! see "We can continue!" 71.5 Interactive Debugger The next example demonstrates the Trace library usage to use the Interactive Debugger Trace(:Debugger) test1() see "good bye!" + nl func test1 x = 10 see :test1 + nl t = 12 test2() # Runtime Error! see "After Error!" +nl see "t = " see t see nl see "x = " see x see nl 71.6 Execute Program Line by Line The next example demonstrates the Trace library usage to execute the program line by line! Trace(:LineByLine) test1() 71.4. Pass Error 814
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  Ring Documentation, Release1.7 func test1 x = 10 see :test1 + nl t = 12 test2() see "After Error!" +nl see "t = " + t + nl 71.7 BreakPoint The next example demonstrates the Trace library usage to stop at a breakpoint! test1() func test1 x = 10 see :test1 + nl t = 12 BreakPoint() see "After breakpoint!" +nl see "t = " + t + nl see "End of program!" + nl 71.8 Disable BreakPoints The next example demonstrates the Trace library usage and how to disable the Breakpoints! NoBreakPoints() test1() func test1 x = 10 see :test1 + nl t = 12 BreakPoint() see "After breakpoint!" +nl see "t = " + t + nl see "End of program!" + nl 71.9 Using the Interactive Debugger The next example uses a Breakpoint to open the Interactive Debugger! load "tracelib.ring" test1() func test1 x = 10 see :test1 + nl t = 12 71.7. BreakPoint 815
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  Ring Documentation, Release1.7 BreakPoint() see "After breakpoint!" +nl see "t = " + t + nl see "End of program!" + nl Screen Shots: We have the Interactive Debugger at the Breakpoint! We can print the variables values We can change the variables values then continue execution 71.9. Using the Interactive Debugger 816
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  Ring Documentation, Release1.7 We can run the Interactive Debugger in the Output Window 71.9. Using the Interactive Debugger 817
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  CHAPTER SEVENTYTWO EMBEDDING RING INRING In this chapter we will learn about embedding Ring in Ring programs and applications. 72.1 Embedding Ring in Ring without sharing the State From Ring 1.0 we already have functions for embedding Ring in the C language. Also we can execute Ring code inside Ring programs using the eval() function. In this release we provide functions for embedding Ring in Ring programs without sharing the state. Advantages: 1. Quick integration for Ring programs and applications together without conflicts. 2. Execute and run Ring code in safe environments that we can trace. Example: pState = ring_state_init() ring_state_runcode(pState,"See 'Hello, World!'+nl") ring_state_runcode(pState,"x = 10") pState2 = ring_state_init() ring_state_runcode(pState2,"See 'Hello, World!'+nl") ring_state_runcode(pState2,"x = 20") ring_state_runcode(pState,"see x +nl") ring_state_runcode(pState2,"see x +nl") v1 = ring_state_findvar(pState,"x") v2 = ring_state_findvar(pState2,"x") see v1[3] + nl see V2[3] + nl ring_state_delete(pState) ring_state_delete(pState2) Output: Hello, World! Hello, World! 10 20 10 20 818
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  Ring Documentation, Release1.7 72.2 Serial Execution of Programs We can execute application after another application using ring_state_main() Example: chdir(exefolder()+"/../applications/formdesigner") ring_state_main('formdesigner.ring') chdir(exefolder()+"/../applications/cards") ring_state_main('cards.ring') 72.3 ring_state_setvar() Using ring_state_setvar() we can set variables value The value could be (String, Number, List or C Pointer) We need this function to quickly pass lists and C pointers to the Sub Ring Environment Syntax: ring_state_setvar(oState,cVariableName,Value) Example: load "guilib.ring" myapp = null win = null func main myapp = new qApp { win = new qWidget() { setWindowTitle("Advanced Example on using ring_state_setvar()") move(100,100) resize(600,400) new qPushButton(win) { setText("Test") setClickEvent("Test()") } # We need this because using load 'guilib.ring' in the sub environment # Will create timers by Qt and closing the window will not be enough # To close the application oFilter = new qAllEvents(win) oFilter.setCloseEvent("myapp.quit()") win.installeventfilter(oFilter) show() } exec() } func test pState = ring_state_init() ring_state_runcode(pstate,"load 'guilib.ring'") ring_state_runcode(pState,"x = NULL") # Pass String ring_state_setvar(pState,"x","hello") 72.2. Serial Execution of Programs 819
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  Ring Documentation, Release1.7 ring_state_runcode(pState,"? x") # Pass Number ring_state_setvar(pState,"x",100) ring_state_runcode(pState,"? x") # Pass List ring_state_setvar(pState,"x",["one","two","three"]) ring_state_runcode(pState,"? x") # Pass Object # We can't pass the Ring Object (win) # Because Objects store pointers to the Class Information # And the class is related to the Parent Ring Environment # And the sub Ring environment can't access it # But we can pass C pointers like win.pObject ring_state_setvar(pState,"x",win.pObject) # Now we create the object again but using the same C pointer # So we have access to the Same window in the parent Ring enviroment ring_state_runcode(pState," new qWidget { pObject = x setwindowtitle('Message from the Sub Ring Environment') } ") ring_state_delete(pState) 72.4 ring_state_new() and ring_state_mainfile() Using ring_state_new() and ring_state_mainfile() we can run Ring programs from Ring programs But unlike ring_state_main(), Here we can control when to delete the Ring state! This is important when we run GUI programs from GUI programs Because they will share the GUI Library (RingQt), And In this case the caller will call qApp.Exec() So the sub program, will not stop and will return to the Main program Here deleting the State of the sub programs will lead to a problem when we run the sub program events So keeping the state is important for sub GUI programs hosted in GUI programs. Example: load "guilib.ring" func main new qApp { win = new qWidget() { setWindowTitle("Test ring_state_mainfile()") resize(400,400) move(100,100) btn = new qPushButton(Win) { settext("test") setclickevent("mytest()") } show() } exec() } 72.4. ring_state_new() and ring_state_mainfile() 820
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  Ring Documentation, Release1.7 func mytest pState = ring_state_new() ring_state_mainfile(pState,"runprogram.ring") # Here we don't delete the state if we will run GUI application # So we can run the GUI application events // ring_state_delete(pState) If you will use this feature, remember to update the previous example based on your application needs So you can call ring_state_delete() at some point to avoid the memory leak! 72.4. ring_state_new() and ring_state_mainfile() 821