Simply being apply to execute our script and view the output isn't + too helpful - we can do that from the command line, or via the web + browser. The real power in debugging comes from the ability to set + breakpoints and step through scripts. A breakpoint is just that - a point + in your script at which you would like to break. What will happen is that + the PHP Interpreter will continue as normal until it reaches the specified + line in your program. When it reaches that line, it will stop and wait for + your instructions as to how to proceed.
To set a breakpoint, move the mouse over the gray bar at the far + left of the margin. Right click beside the line at which you want to + break, and select the option 'Toggle Breakpoint'. Ensure you select + 'Toggle Breakpoint' and not 'Toggle PHP Breakpoint' - the latter will not + work. After you toggle the breakpoint, a blue ball should appear in the + gray margin beside the line you specified.
After you have added your breakpoint, select Debug
+ History-myFirstProject (or whatever name you gave your configuration) from
+ the Run menu.
Now, to view our debug information, we need to change to our Debug + Perspective. To do this, select the Window drop down menu and select Open + Perspective-Debug.
There are a number of things you will notice on the Debug + perspective. The top left has a list of scripts that are currently + running. There are button in this pane that can control the execution of + the script. The first button labelled in the diagram is the Resume button. + Clicking on this button will cause execution of your script to resume + until it reaches the next breakpoint. The second button that is labelled + is the Terminate button. This button will cause execution of your script + to terminate. The third button and fourth buttons are the Step Into and + Step Over buttons. These will both cause one line of your script to run. + The difference between the two is that the Step Into button will expand + any function calls on the line, and the step over button will treat + function calls as one line. So, if you are not worried about the functions + that are being called on a given line, you should use Step Over. If you + want to see exactly what the functions are doing, you should use Step + Into.
To the right of the Debug pane you will see a pane with a Variables + tab and a Breakpoints tab. In the variables tab, you will see a list of + variables that are in the current scope. Our script uses two variables - + $i and $output. You will notice that a number of environment variables are + also listed. Along with the list of variables, you can see the values of + those variables. This is useful if you want to track what happens to a + variable over the course of execution of your script. Clicking on the + Breakpoints tab will allow you to see a list of breakpoints that have been + set for your script. From this tab, you can turn breakpoints on and off by + checking or unchecking the checkboxes that are beside them. There are also + buttons to remove selected breakpoints and to remove all breakpoints for + your script.
Underneath, you will see an editor containing the current source + file that is being executed. A blue arrow generally follows execution of + your script. At the very bottom is a window that displays the Console + where you can see the output of your script.
