Bugfix: term.Literal.__add__

[pinbe]

As long as Literal(1) is internaly casted by int, Literal(1) + Literal(1) may return Literal(2) instead of Literal('11').

[gromgull]

That is the intended behaviour. Literal comparisons and operations are done in value space to make it easy to implement the SPARQL engine. See https://rdflib.readthedocs.org/en/latest/upgrade3to4.html#datatyped-literals

[gromgull]

Wait - I may have been too hasty :)

[pinbe]

Le 29 janv. 2015 à 15:08, Gunnar Aastrand Grimnes notifications@github.com a écrit :

Wait - I may have been too hasty :)

Thank you your reply. I was preparing a more detailed explanation, just below :-) just bellow.

Regards.
Benoît Pin.

---

Thank for your reply: You confirms that comparisons and operations should be done in the value space.
Actually, this information also confirm the Literal.add method is buggy.
The bug report was probably too short.
Let me explain longer:

Here's two literals that are integer values

>>> one = Literal(1)
>>> two = Literal(2)
>>> print one.datatype, two.datatype
http://www.w3.org/2001/XMLSchema#integer http://www.w3.org/2001/XMLSchema#integer

Now, let's do the sum with the current rdflib version

>>> print one + two
12

This buggy result denotes that the sum has been made in the lexical space.

After applying the proposed fix, you will obtain the correct result in the value space.

>>> print one + two
3
>>> print (one + two).datatype
http://www.w3.org/2001/XMLSchema#integer

[nicholascar]

Replaced by PR #978 which is updated with commits since this PR and also new tests for move addition value and type combinations