"Nick Sabalausky" <[email protected]> wrote in message news:[email protected]... > "Ellery Newcomer" <[email protected]> wrote in message > news:[email protected]... >> >> For some reason, my professor seems to be skipping LR parsing. > > Gold's documentation has a lot of good starting point information: > > http://www.devincook.com/goldparser/articles/lalr.htm > http://www.devincook.com/goldparser/doc/meta-language/index.htm > http://www.devincook.com/goldparser/doc/engine-pseudo/index.htm > > LR's are typically considered a little more powerful than LL (although > ANTLR has pushed LLs impressively far), and they work in basically the > opposite way. If you have: > > A --> B1 | B2 > B1 --> "foo1" | "foo2" > B2 --> "foo3" | "foo4" > > An LL, as you know, starts at the A and works it way down. But an LR > starts by matching one of those "foo"s and then works it's way up by > reducing to one of the Bs and then to A. >
Also, you can use GOLD to actually step through the parsing process, so that's a very good way to get the hang of what's going on in an LR.
