Re: Templating: a proposed way forward

On 22 Sep 2014, at 10:30 , Jeni Tennison <jeni@jenitennison.com> wrote:

> Hi all,
> 
> Thanks to all those who managed to attend the telcon on Wednesday. Those of you who didn’t, please read the minutes at http://www.w3.org/2014/09/17-csvw-minutes.html for background.
> 
> Based on our charter, we need to deliver a default mapping of CSV to RDF/XML/JSON, informed by the basic metadata specified in [1]. These conversions will need to address some particular user needs, which might include:
> 
>   * specifying the names/URIs of properties/elements/attributes
>   * specifying the datatypes of values in the target format
>   * specifying how values map to URIs where appropriate
>   * handling list values
>   * handling default values when values are missing
>   * converting sets of CSV files into a single output
> 
> There is a limit to what can be easily articulated through properties in a metadata document however, without it becoming extremely unwieldy.
> 
> Jeremy’s analysis of the use cases demonstrate that we have very few use cases that include a specification of the converted format, and those that do are relatively simple. I think it was also Jeremy who pointed out on the call that the places where conversions are usually hard are when targeting pre-defined formats such as Data Cube or vCard, where there need to be more complicated mappings between the data you have and the format you want to create.
> 
> On the call, Stasinos suggested:
> 
>   * we define how to point out to templates for conversion from metadata files
>   * we support implementation defined (extension) template languages
>   * we define a basic template language and conformance level around that

To be clear: do we (should we) consider this as yet another option compared to what was discussed on the call? Of course, the devil is in the details: what does 'basic' mean? Does it mean that the language does not cover all the issues listed above?

> 
> Andy suggested the the work to define a basic template language could be done within a Community Group rather than within this Working Group, depending on the interest and time commitment that the Working Group can make.
> 
> I want to reiterate one particular point that was made during the meeting: the Working Group as a whole can only do what the members of the Working Group do. Regardless of whether we pursue the specification of a templating language, we still have need for volunteers to edit the specs for:
> 
>   * default conversion to RDF
>   * default conversion to XML
>   * default conversion to JSON
> 
> Perhaps the biggest question we have about a templating language is actually about the Working Group being able to commit the time that it would take to specify it, including all the tests that would be required and the need for implementations. Having someone volunteer to edit the spec, someone volunteer to manage the test suite, and two people volunteer to implement the spec (some of these volunteers may be the same people), would make me at least feel a lot happier about taking this on within the Working Group.
> 
> Anyone feel they can step up?
> 
> We will discuss this again this week. If we can’t decide then we’ll defer a decision until the face-to-face at TPAC at the end of October.
> 
> Cheers,
> 
> Jeni
> 
> [1] http://w3c.github.io/csvw/metadata
> --  
> Jeni Tennison
> http://www.jenitennison.com/
> 


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Ivan Herman, W3C 
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