#893 proper Jython debugger
Since the beginning the biggest feature I miss from IDL is debugging, and I've tried to use pdb and parsing its output and developing a debugger, but it's never been reliable enough to have others use it. While working on https://sourceforge.net/p/autoplot/feature-requests/892/ (floating output bubbles) I asked ChatGPT if it had ideas about how a debugger could be developed, and there have been hooks hiding in Jython 2.1 this whole time. (Things changed at Jython 2.2, which is probably why I never found documentation on this.) Within hours I had a proper debugger where I could trace code and add breakpoints. This is the ticket describing this new functionality.
The scientist should be able to:
- trace script execution with an arrow showing the line being processed ("program counter")
- breakpoints will allow execution pause. The "Run" button will be replaced with a "Resume" button
- stepping through code will be done with the shift key and Resume.
- a breakpoint can be disabled, so that its position is kept.
- a breakpoint will evaluate and print an expression when hit, replacing the need for "debug print" statements. A disabled breakpoint will still be print its expression.
- Breakpoints are an object so that they can be extended, for example to include hit counts.
The LineNumbersRuler (a.k.a. "Gutter") is extended to indictate the position of the program counter and breakpoints. Grey breakpoints indicate disabled.
Discussion
My session with ChatGPT reminds that Lines of the Document object should be used, so that breakpoints will move around as code is modified. This needs to be done as well.