query functions should convert data into values in domains supported by incanter about grafter

[RickMoynihan]

Hi James,

Could you supply some simple illustrative code examples of what you'd like this to look like as a user?

Regarding Incanter types; to my knowledge you can put any object in a cell... We currently put URI's in cells, and on 0.6.0-SNAPSHOT there are changes that will capture errors (Exception objects) and put them in the cell where they occurred.

[lisp]

yes, it is evident that one can put any value in a cell.

if there is some reason to retain that practice without restriction, for our use case, we would have to enforce conversions at the interface to weka datasets.
we are not heavy incanter users. our use case is to provide an interface which permits one to apply those tools to data retrieved from a repository and produces no surprises in the process. in that sense there is great appeal in following the conventions which are said to apply in that environment : https://incanter.files.wordpress.com/2009/06/9781782162643_chapter-6.pdf

The data in each cell of an Incanter dataset can be a string or numeric

This may be a narrow interpretation, but it is reinforced by the nature of its associated analytical libraries. Perhaps this argues for alternative dataset classes, each with a conversion protocol at the interfaces.

[RickMoynihan]

One thing we're planning on doing is at some point migrating to use an implementation of the core.matrix PDataset protocol; that will allow us greater flexibility in providing different types of Dataset with different performance properties etc.