alt Hacker NewsHate to agree, but it is true. For a while, I think, the main sequencing framework was in perl (Bioperl). Not sure what was best for structures - possibly Biojava?
It is very tempting, though - 'just' make a nice, clean API in your favourite language (eg Haskell, Ruby, ...) and everyone will flock to use it! Maybe.
Why don't you mention Biopython? Bioperl is already too old and not much up-to-date with newest data.