Re: Graph Fragments Templates

Hi Andy,

thanks.

My problem is not with these simple cases. My problem is to understand how templates will be combined with the metadata definition in general; at the moment these are fairly disconnected.

Looking at the latest draft of Jeni, each field may have its own particular set of properties (although some of them can be set for the column as a whole, it can be specialized for a specific field). This means that a pattern of the sort

	<something> <something> {colname} .

may become slightly underspecified. For example, in your example, you translated the metadata including a datatype definition into something like

	<something> <something> {colname}^^xsd:double

but that may not be o.k.; it should be something like

	<something <something> {colname}^^xsd:{{datatype}}

where '{{datatype}}' is my ad-hoc syntax to denote the _value_ of the property "datatype". Actually, it may become more complicated insofar as the datatype value should probably not be taken verbatim, ie, if it says 'number', than it should be translated to its xml schema counterpart (either we include an if-then-else into the template language or we have to write down a specification on how exactly the template processor works for each field and its properties). Another example is the 'separator' field; if a field includes a 'separator' property, then the result of the template expansion may become something like

	<something> <something> (l1 l2 l3 l4) .

It all can be done of course. But, unless we keep the templates completely disjoint from the metadata (which I think would be a mistake) we have quite some work to do reconciling the templates with the metadata definition:-( Did you have any thought on that already?

Ivan

P.S. Sorry, I am off-line at the moment due to a power outage, I cannot check Gregg's older document; maybe he did deal with these.
 


On 21 May 2014, at 19:46 , Andy Seaborne <andy@apache.org> wrote:

> I have written up more on graph templates:
> 
> https://github.com/w3c/csvw/blob/gh-pages/examples/graph-templating.md
> 
> 	Andy
> 


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