"Place of definition" for macros in the Widget Info dialog

[abrahamwolk]

At ESS, we are thinking of implementing an addition to the "Widget Info" dialog in the Display Runtime that displays where macros were defined. The motivation for this feature is to facilitate finding the place of definition of macros, which can help when changing or debugging an OPI.

Do other sites also think that this would be a useful feature to add?

[kasemir]

Well, yes, it could be useful to know that. But the request seems a bit naive. How do we provide that info, would it truly be useful and still be efficient?

In the shell, you can echo $PATH but there's no way to see how/where that value was set. You need to fgrep PATH around the system to see where it's all touched. Same with

int i=1;
i=2;
System.out.println("i = " + i);
// There's no way to ask i when/where it was last set...

How do you want to track the place/time of definition for each macro?
A macro would not only carry its value but also some string that describes when it was last set.
Like "Button 42 in parent display /path/to/that/display.bob".
In there, you might see that X=$(P):$(Q). So now you need to go back to /path/to/that/display.boy in the runtime(!) to see what the values of P and Q are, and where they originate. Do you want to carry around the whole history of each macro value, a tree like

X=$(P):$(Q) set by Button 42 in parent display /path/to/that/display.bob.
|
+-- P="Hello" set by display properties of /path/to/that/display.bob
+-- Q="World" set by button 13 in parent display /path/to/other/display.bob

[abrahamwolk]

Well, yes, it could be useful to know that. But the request seems a bit naive. How do we provide that info, would it truly be useful and still be efficient?

That is the key question!

In the shell, you can echo $PATH but there's no way to see how/where that value was set. You need to fgrep PATH around the system to see where it's all touched. Same with

int i=1;
i=2;
System.out.println("i = " + i);
// There's no way to ask i when/where it was last set...

How do you want to track the place/time of definition for each macro? A macro would not only carry its value but also some string that describes when it was last set. Like "Button 42 in parent display /path/to/that/display.bob". In there, you might see that X=$(P):$(Q). So now you need to go back to /path/to/that/display.boy in the runtime(!) to see what the values of P and Q are, and where they originate. Do you want to carry around the whole history of each macro value, a tree like

X=$(P):$(Q) set by Button 42 in parent display /path/to/that/display.bob.
|
+-- P="Hello" set by display properties of /path/to/that/display.bob
+-- Q="World" set by button 13 in parent display /path/to/other/display.bob

For an initial implementation, I propose to keep track of the last place of definition. In this example, the information that would be kept track of is that the macro variable X was defined in Button 42 in display /path/to/that/display.bob. This information could be displayed in a new column "Place of definition" in the tab "Macros" in the "Widget Info" dialog.