Enju is a syntactic analyzer for English. A grammar is based on Head-driven Phrase Structure Grammar (HPSG), which is a linguistic theory for syntax. Since this system computes more detailed structure of sentences than CFG parsers, you can obtain various information such as predicate-argument structures.
For example, Enju can parse the following sentence,
It's falling like a stone, said Danny Linger, a pit trader who was standing outside the London International Financial Futures Exchange.and you will get the results that the subject of "said" is "Danny Linger" and the complement is "it's falling like a stone", and the subject of "standing outside..." is "pit trader".
If you have a web browser that supports XHTML and XSLT (Mozilla Firefox etc.), you can browse the parse results of the above sentence.