Surprising literal comparisons

[jesper-friis]

The following comparisons between a Literal and another object may be surprising:

In [7]: Literal("abc", datatype=XSD.string) == "abc"
Out[7]: True

In [10]: Literal(1, datatype=XSD.int) == 1
Out[10]: False
 
In [11]: Literal(1, datatype=XSD.int) == "1"
Out[11]: True

This is an unintended consequence of Literal being a subclass of str.

A suggestion is to add an __eq__() method to Literal that uses tripper.utils.parse_literal() to convert all non-literal objects to a Literal and then require that value, lang and datatype all must be equal for equality to be true.

[jesper-friis]

Adding __eq__() (and __hash__()) to Literal causes failures in mapping due to the changed comparison logics.

Updating mappings to the new behaviour of literal comparisons may require little more effort. Are there also some third party libraries that depends on tripper that we will break?