At 04:54 PM 7/8/02 -0400, Dan Sugalski wrote: >A continuation is a sort of super-closure. Like a closure it captures >its lexical variables, so every time you use it, you're referring to >the same set of variables, which live on until the continuation's >destroyed. This works because the variables for a block are kept in a >scratchpad--since each block has its own, and each scratchpad's mostly >independent (mostly). > >Now, imagine what would happen if the 'stack', which we track block >entries, exits, sub calls, and so forth, was *also* done with a linked >list of scratchpads, rather than as a real stack. You could have a >sort of "super closure" that both remembered all your scratchpads >*and* your spot in the call tree. That, essentially, is what a >continuation is. We remember the scratchpads with variables in them >*and* the scratchpads with stack information in them. > >When we invoke a continuation, we put in place both the variables and >call scratchpads, making it, in effect, as if we'd never really left >the spot we took the continuation at. And, like normal closures, we >can do this from wherever we like in the program.
So if you could serialize a continuation, you could freeze your program state to disk and restore it later? Cool, makes for easy checkpoint/restarts. -- Peter Scott Pacific Systems Design Technologies http://www.perldebugged.com/
