I used Smalltalk for a while, so I at least had this rich debugger experience there: being able to change code whilst halted at a breakpoint and resume with the

I used Smalltalk for a while, so I at least had this rich debugger experience there: being able to change code whilst halted at a breakpoint and resume with the new code taking effect immediately, no world recompilation needed; being able to compose complicated queries in the debugger to do consistency checking of live data structures I was looking at, stuff like that. The thing is, I did not learn any of that from a book, I had to learn it from someone else who knew it. Thanks for the details, sounds like I need to look at DDT too. I can't remember where I read this, but I think it was about Marvin Minsky, a story about programming in the debugger, where the subject started out with an empty program, ran it which immediately put him in the debugger, and there he just built up the program a statement at a time to handle whatever the program needed to do at the step it was currently at, and it would just dump him to a breakpoint every time it got to a part where he had not yet specified what was to be done. The whole program was eventually composed in one debugging session starting from an empty program. I suspect this must have been done in DDT, or something much like it. Does that sound plausible to you?