added utilities for URI slug generation

[FND]

this allows for converting arbitrary strings to URI slugs:

label = "hello world"
IqRdf.send(label, IqRdf::Skosxl.Label)
# results in invalid data: `:hello world a skosx:Label.`

label = "hello world"
IqRdf.send(IqRdf::Origin.new(label).to_s, IqRdf::Skosxl.Label)
# results in valid data: `:helloWorld a skosx:Label.`

adapted from iQvoc:
https://github.com/innoq/iqvoc/blob/0cfa829283da64dc4035b5a1c9ada255a1407bce/lib/iqvoc/origin.rb

arguably IqRdf should do this automatically - or at least validate URIs
accordingly?

however, perhaps this iQvoc Origin is overkill and URL-encoding
(i.e. :hello%20world) suffices?

[tillsc]

I think automatically url encoding things would be enough.

[FND]

I would prefer that as well, but when I was experimenting with this, it seemed like URL-encoding was not valid in QNames - at least Sesame's Turtle parser rejects such triples ("Expected an RDF value here, found '%'")

[tillsc]

You're right. One more reason to do this automatically :-)

[tillsc]

http://www.w3.org/TeamSubmission/turtle/#name :

name    ::= nameStartChar nameChar*
nameStartChar   ::= [A-Z] | "_" | [a-z] | [#x00C0-#x00D6] | [#x00D8-#x00F6] | [#x00F8-#x02FF] | [#x0370-#x037D] | [#x037F-#x1FFF] | [#x200C-#x200D] | [#x2070-#x218F] | [#x2C00-#x2FEF] | [#x3001-#xD7FF] | [#xF900-#xFDCF] | [#xFDF0-#xFFFD] | [#x10000-#xEFFFF]
nameChar    ::= nameStartChar | '-' | [0-9] | #x00B7 | [#x0300-#x036F] | [#x203F-#x2040]

[FND]

two issues:

• What's the right place to perform this conversion automatically?
• Looking at the diff again, the whole thing looks far more complex than it should be.

[tillsc]

It isn't: https://github.com/innoq/iq_rdf/blob/master/lib/iq_rdf/uri.rb#L24

[FND]

¿Qué?