I'm looking for a way to do searches with FAST Search Server 2010 based on Regular Expressions.
For instance, I'd like to be able to use:
And have it return any content that looks like a Social Security Number. Any ideas?
This is not possible as FAST supports FQL (FAST Query Language) and not regular expressions.
Your best bet is to create an external processors which uses regexp to find social security numbers.
If you find a match, assign the value "true" or similar to a crawled property. Then create a managed property of type bool which you map this crawled property. When searching you can then do a query like: hassocial:1, which will return all items with this flag set.
There is no way to do this.
What you can do is detect security numbers at indexing time (with regex if you want) and add them to a managed property like "detectednumbers".
Then you can query document that contains a number, or only document that contains a specific number.
I'm afraid this is the only way to go.