[fiddlerwoaroof]

Also, little story: once I had to migrate a large database between an old, schemaless, version of a product to a new one that enforced schemas. Because the old version was schemaless, there was a whole host of minor schema issues. For various reasons the migration process already involved a Python script spawning an older version of Python and communicating with it over a pipe. I started running the migration and it failed 20 minutes in, so I fixed the issue and restarted the migration only for it to fail differently 20 minutes in. At this point I wrote some code to catch the exception, spawn a prompt that let me input the appropriate conversion code that got evaled and added to a dictionary of translators, along with a function to determine if the conversion applied. This way, every 20 minutes or so I’d come across a new form of corruption and add a translator to fix it without restarting the whole process.

When I learned CL, the condition/restart system and pervasive hot code reloading reminded me of my Python hack and how much easier it would have been in a language designed for this sort of programming.