6.2 Literal Predicates
predicate
(has-datatype-iri? val) → boolean?
val : literal?
Returns true if this literal has a datatype URI.
predicate
(has-language-tag? val) → boolean?
val : literal?
Returns true if this literal has a language tag.
predicate
(has-xsd-datatype? val) → boolean?
val : literal?
Returns true if this literal has a datatype URI and that URI is in the XML Schema namespace.
Returns true if this literal has a datatype URI and that URI is equal? to "datatype".
Returns #t if v1 and v2 are literal? values, and v1 is
lexigraphically less than v2. This test is applied to all three components of the literal,
where these are optional the value #f is ordered less than any string.