Data specification catalog


Hi. We work with source data from various sources and in various different formats and layouts. I'm trying to create a central data format/specification catalog where I can keep all these specifications and extract the specification base on a key that I pass to a function. I don't want to re-invent the wheel, so are there any existing packages that can do this. If not, any pointers as to what detail I need to specify for each file type? The basic stuff like column_name and column_type, but what else can be handy?