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Taking the Pain Out of Debugging With Live Programming
angry tapir writes "'Everyone knows that debugging is twice as hard as writing a program in the first place,' Brian Kernighan once wrote (adding: 'So if you're as clever as you can be when you write it, how will you ever debug it?') However, Sean McDirmid, a researcher at Microsoft, has been working to remove some of the pain from debugging. McDirmid, based at Microsoft Research Asia, has been studying ways of implementing usable live programming environments: a solution that is less intrusive than classical debuggers. The idea is to essentially provide a programming environment in which editing of code and the execution of code occur simultaneously — and in the same interface as code editing — with tools to track the state of variables in a more or less live manner."
Have you tried the new VS2012? They took a shotgun to the UI and the file menu is still screaming from the trauma.
They've reinvented Smalltalk. Let's party like it's 1980.
I suspect you haven't seen a Common LISP debugging environment. Yes, they allow breakpoints, as well as live code modification. (And if you were lucky enough to have a LISP machine, you could dive into the code behind your libraries, your operating system, etc. -- updating state on the fly, all the way back to tweaking a driver on a running machine... on the fly, in LISP).
What we have these days (say, Clojure's nrepl) isn't as powerful as that, but it's pretty damned powerful even so. Want to tie into your production system and see what a new version of a function would do against currently live production data, without actually changing the production system's behavior? If you're writing purely functional code, you can do that trivially... and the language strongly encourages pure functional code (as opposed to many "modern" languages where trying to write things to be side-effect-free is working against the grain).
If the best example you can think of is QBasic, you have no idea what a REPL can do.
Welcome to VB.Net. It's been there for ages. Mind you you have to pause the debugger to edit the code, but that's probably a good idea anyway. VB.Net also has some of the best pre-compile (it has a background compiler) syntax checking of any language I've ever seen. The only time you actually have to compile the program is when you want to run it, you never have to compile to make changes show up for auto-complete. And once you're running in the debugger you can edit the code anytime the code is stopped. There's a few limitations. I'm not sure if you can add a whole class while it's running, but you can definitely fix all those little off-by-one errors and continue running the program.
Anthropic principle: We see the universe the way it is because if it were different we would not be here to see it.