Convert the lexical form of literals to a canonical form.
Two literals can be different RDF terms for the same value.
Examples include (first shown of the pair is the canonical form):
"1"^^xsd:integer and
"+01"^^xsd:integer
"1.0E0"^^xsd:double and
"1"^^xsd:double
The canonical forms follow XSD 1.1
2.3.1 except in the case of xsd:decimal where it follows the older
XSD 1.0 which makes it legal for Turtle's short form (
"1.0"^^xsd:Decimalrather than
"1"^^xsd:decimal). See XSD 1.0
3.2.3.2
Canonical representation
The effect on literals where the lexical form does not represent a
valid value (for example,
"3000"^^xsd:byte) is undefined.
This option is off by default.
This option can slow parsing down.
For consistent loading of data, it is recommended that data is cleaned and
canonicalized before loading so the conversion is done once.