On Apr 10, 2008, at 4:48 PM, Gregory Stark wrote:
Well I feel like storing a query and resending it later is something predictable which will work reliably. Storing a psql input line andreinterpreting it later is surely going to cause weird things to happen.Just for some examples off the top of my head, what happens if I define an alias "\foo" which consists of "\foo" and call it? What happens if I have mutually recursive aliases? What happens if I define "\foo" to run \ followed by its first argument, and I pass it "foo"? What happens if I pass it "unaliasfoo"?
As Bernd said, I see this as simple search and replace, and then stick it in the command buffer. If you define an alias that calls itself, you could end up with a stack overflow, same as with server functions.
What happens if you press C-c during an alias, does it keep running subsequent commands? What if the editor returns an error after a \e command? What aboutif a \i command doesn't find the file?
You throw an error. In shell, you can use && to control if you keep going or not after that; perhaps we should have that.
Basically it sounds like you're treating psql as if it was a well defined language with well defined syntax and semantics. And I don't think it is. It's just one big if-else-if block with lots of strcmps. There's no infrastructureto parse or manage a stack of calls to functions.
So perhaps we should change that. Don't get me wrong, psql is the most powerful command-line database I've ever seen, but it still irritates me that it's not more shell-like in nature. In particular, the inability to do things like condition processing, or save the results of an SQL query into a psql variable are very annoying. If that (or aliases) means psql needs to be more than a big IF-THEN-ELSE then I think that's part of what we should do.
-- Decibel!, aka Jim C. Nasby, Database Architect [EMAIL PROTECTED] Give your computer some brain candy! www.distributed.net Team #1828
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