One of the real advantages of Smalltalk development is something very simple - the Smalltalk Workspace.

In fact, the code snippet you see at the top is one I use quite a bit. When I have people send me "I can't subscribe to this feed" emails, the first thing I usually do is try the url in the first code snippet above (which is an unfactored version of what BottomFeeder does). The advantage of doing it in a workspace like that is that I can bypass the application level exception handling (sure, I could throw breakpoints into the code, and I often do).

The nice thing about the workspace environment is the ability to try small snippets of code out, long before I get to creating classes (in development) or as simple test harnesses. You can save the scripts, which is what I've been doing with the above for a couple of years now. Sure, there are things like this in some Java environments - but they really aren't the same thing. Those things compile a fake class behind the scenes to wrap what you have - and I don't know that you can slap a halt in a workspace script in (say, Eclipse) and end up in the debugger. In Smalltalk, I can do that, and I do it quite often.

Heck, one of the cooler variations on this is slapping a halt into an SSP page. When I first started building the Silt Server, I had virtually no idea how that style web app worked - I'd been using VisualWave, which is much more abstract (but also more limited in some ways). As a result, my pages would often render oddly, or give me (what I thought were) bizarre results. What to do? Slap a halt in there, something like this right on the page:

<% self halt. %>

Now, the nice thing is, the environment that web toolkit applications run in is a lot like a workspace page - which makes it nicely interactive. I learned a lot about the way things worked doing that. You can approach this level of interactivity in some of the Java environments, and in the MS environments - but you can't quite get there. I'm not maintaining that it's a physical impossibility to do so - but the fact that nothing comes close tells me that the effort required must be really, really large :)