#Free script debugger how to
#Free script debugger code
#Free script debugger series

#Free script debugger code

Code evaluated through QScriptEngine::evaluate() without a name specified, will be displayed in the widget as Anonymous. When a script is no longer referenced by the debugger target it is removed from the scripts widget. Clicking on a script will cause its code to be shown in the code widget. The scripts widget shows the scripts that are currently loaded in the script engine. This is however possible from the command-line interface, see Console Command Reference. The code widget is read-only it cannot currently be used to edit and (re)evaluate scripts. A breakpoint has to be set on a line that contains an actual statement in order to be useful.When an uncaught script exception occurs, the offending line will be shown with a red background. Clicking in the margin of a line will cause a breakpoint to be toggled at that line. The widget displays an arrow in the left margin, marking the code line that is being executed. The code widget shows the code of the currently selected script. While typing, you can press the TAB key to get possible completions for the expression. The expression will be evaluated in the associated stack frame. Double-click on the value and type in the new value the value can be an arbitrary expression.

Properties that are not read-only can be edited. Properties whose value has changed are shown in bold font.

Objects can be expanded, so that their properties can be examined, recursively. The locals widget shows the variables that are local to the currently selected stack frame that is, the properties of the objects in the scope chain and the this-object. To select a particular stack frame to inspect, click on its row. A row contains the frame index (0 being the inner-most frame), the name of the script function, and the location (file name and line number). Each row represents one frame in the stack. The stack widget shows a backtrace of the script execution state. Typing 'x = 123' will assign the value 123 to the variable x in the current scope (or create a global variable x if there isn't one - scripts evaluated through the console can have arbitrary side effects, so be careful). For example, typing 'x' and hitting enter will evaluate 'x' in the current stack frame and display the result. The console provides a simple and powerful way of manipulating the script environment. Commands and script variables are auto-completed through the TAB key.Īny console command that causes a change in the debugger or debugger target's state will immediately be reflected in the other debugger components (e.g. The set of commands and their syntax is inspired by GDB, the GNU Debugger. The console widget provides a command-line interface to the debugger's functionality, and also serves as an interactive script interpreter. The following table describes each component and how they relate to each other.

#Free script debugger series

The debugger's functionality is divided into a series of components, each being a widget that can be shown in the main window of the debugger. It will be invoked again if one of the conditions described in the list above is met. The debugger will resume, i.e., give the control back to the script engine, when the user clicks Continue menu item from the Debug menu. Once the debugger is started, the execution state can be inspected, e.g., the value of variables can be queried and the current program stack shown. An uncaught script exception is thrown.Clicking the Interrupt menu item from the Debug menu in the main window.The debugger statement is encountered in the script.The debugger will start, i.e., take control over the script's execution when any of these conditions are met: The following image shows the debugger as created with standardWindow(): We assume that the debugger has been integrated into the application through the QScriptEngineDebugger::standardWindow() function, which provides the standard debugger configuration. We assume that the reader is somewhat familiar with general debugging concepts and existing debugging tools.

#Free script debugger how to

This manual describes how to use the debugger. Application developers can embed the debugger into their application through the QScriptEngineDebugger class. The Qt Script Tools module provides a debugger for script execution in Qt applications that use Qt Script.