Dan Sugalski <[EMAIL PROTECTED]> writes:
Okay, now that we're well on our way to getting sub/method/whatever calling down and working, I want to point us towards what I'm thinking of for exceptions.
Exception handlers really strike me as anonymous lexically scoped subroutines that get called with just one parameter--the exception object. As far as the engine should be concerned, when an exception is taken we just take a continuation with the address being the start of the code that handles the exception. They need to get pushed on the system stack so we can walk up it at runtime when an exception is called looking for handlers.
So, we grab another register for 'current exception continuation'?
Nope. The exception goes onto the control stack. When an exception is thrown we walk up the control stack frames until we find an exception handler entry, at which point we invoke the continuation associated with it, passing in the exception information. (Though we may put the exception info out-of-band, since I can see wanting to retain all the registers for Truly Clever exception handlers...)
--
Dan
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Dan Sugalski even samurai
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