Hey, the main idea of PP-Islands project is to allow for only partially defined grammars. If you have a source without a grammar for it, you define only part of the grammar (that part, that interests you) and you omit the rest (to save time/effort). The island parsers should make sure that your pieces of interests (islands) will be extracted and the rest (water) will be skipped.

E.g. we can extract method names from Java files with precision around 95% with a parser with 10 rules.

Cheers,