hey thanks a lot Mr.Akim and Mr.Derek for your feedback;
I checked out bison sources from cvs; there is absolutely no documentation that I could find on bison's internal data structures. So I thought I would put that down on a blog for now as I study the code. I will let you know when I create the blog. It looks like I will definitely need a helping hand. I will ping you when I am deep enough into the rough waters of bison :) regards Satya. On 5/9/06, Akim Demaille <[EMAIL PROTECTED]> wrote:
Le 9 mai 06 à 17:36, Derek M Jones a écrit : > Akim, > >>> The main requirement is to resync so that cascading syntax errors >>> are avoided. One compiler I worked on did multiple parses, using >>> different combinations of error recovery, looking for the one that >>> parsed the largest amount of input (up to some limit) without >>> generating any other syntax errors. >> What was the underlying technology of the parsers? I guess it was >> LL, right? Were they written by hand? > > It was yacc running under Unix version 7 on a PDP-11 cross > compiled to a mainframe. Our users only got a few goes at > compiling their code everyday (it was a mainframe batch > environment) and it was very important that the compiler > did its best to generate them some kind of executable so > at least they might be able to try out some parts of the code. > > All the best error recovery I have every seen occurs in compilers > running on mainframes. Not because the cost of renting the software > was an arm and a leg, but because the users got to have so > few goes at compiling in a day. Yep, I knew most of the value is there. In fact, that's also very clear when one reads Corbett's PhD, on "semantical" error recovery, which prompted him to write what today is named Bison :) (He was no aiming at main frames though. I don't think Pascal ever run on main frames. But that's just my guess.) I'm just stunned that you had such an elaborate error recovery system on top of stock yacc!
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