Re: Reflection on the special telco of CSVW - more details on Alternative 2.5

On 17 Sep 2014, at 12:42 , Dan Brickley <danbri@google.com> wrote:

> On 10 September 2014 08:58, Ivan Herman <ivan@w3.org> wrote:
>> 
>> As a followup on my previous mail...
>> 
>> I wanted to see whether it is complicated to implement a very simple template (Alternative 2.5 in [1]) using existing tools, ie, to make it quickly available, with some extra work, to the community at large. I think the answer is yes;
> 
> Personal opinion: I think the answer is 'yes' too, after some similar
> experimentation and talking to a bunch of people. I believe we have a
> very good chance of doing substantially better than 100% mechanistic
> mappings, roughly around the level of Mustache ("Logic-less", but with
> simple conditionals) with some regex pre-processing and a few
> W3C-oriented supporting functions.
> 

Actually, what I have is even simpler. In the 'filtered-templates' branch of the repo[1] what I have in the readme is:

[[[
- `{{#rows}}` - `{{\rows}}` (where `rows` is a fixed symbol) at the beginning of a line means that the full templates enclosed between these two lines are to be repeated for all rows of the CSV content.
- `{{name}}` has two possible roles:
	- if used *within* a `{{#rows}}` - `{{\rows}}` context, `{{name}}` refers to a column name, and the template is replaced with the content of the corresponding cell
	- if used *outside* a `{{#rows}}` - `{{\rows}}` context, `{{name}}` refers to a top-level key in the metadata **if its value is a string**; the template is replaced with the corresponding value
- `{{name}}` can also have *filters*. The tag can have the format: ``{{name.f1.f2.….fn}}``, where ``f1,…,fn`` are filter functions. A filter function may have argument, i.e., it may look like ``fi("a","b")``; the arguments are strings surrounded by the ``"`` or the ``'`` characters. If there are no arguments, the argument list can be dropped altogether. Filter functions are invoked with: the output of the previous filter or the value corresponding ``{{name}}``; the reference to the metadata object; the list of the arguments (strings) if applicable. The filter function must return a replacement for the template value.

The list of available filter functions will be specified by the WG, and a mechanism to add a user-defined filter will be provided. At present, there are only a few filters, these are ``upper``, ``lower``, ``concat(str)``, ``replace(regexp,str)``.
]]]

That is it. Ie, no conditional and variables, nor any regex preprocessing (except for the "replace" filter)

Ivan


[1] https://github.com/w3c/csvw/tree/filtered-templates



> I believe there is also a very good chance that a *simple* technology
> like this will be picked up by search engines as a way of getting
> graph-oriented data (schema.org and suchlike). But I also believe that
> we could find this effort bedevilled by creeping complexity and that
> there's some risk it might not make it to W3C REC. It's worth trying
> though!
> 
> </opinion>
> 
> Dan
> 
> 
>> look at:
>> 
>> https://github.com/w3c/csvw/tree/gh-pages/experiments/simple-templates-jquery
>> 
>> for further details. See
>> 
>> https://github.com/w3c/csvw/tree/gh-pages/experiments/simple-templates-jquery/simple_test
>> 
>> for the test I used so far.
>> 
>> The implementation is rough at the edges, and I am still in the process to make it a bit better code-wise. But that still gives, I hope, an idea of where this *may* go.
>> 
>> [1] http://lists.w3.org/Archives/Public/public-csv-wg/2014Sep/0006.html
>> 
>> ----
>> Ivan Herman, W3C
>> Digital Publishing Activity Lead
>> Home: http://www.w3.org/People/Ivan/
>> mobile: +31-641044153
>> GPG: 0x343F1A3D
>> WebID: http://www.ivan-herman.net/foaf#me
>> 
>> 
>> 
>> 
>> 


----
Ivan Herman, W3C 
Digital Publishing Activity Lead
Home: http://www.w3.org/People/Ivan/
mobile: +31-641044153
GPG: 0x343F1A3D
WebID: http://www.ivan-herman.net/foaf#me