fn.functionAvailablefn.functionavailablefnfunctionavailable/apidoc/8.0/fn:function-available.xml
Returns true if and only if there is a function whose name and optionally
arity matches the value of the $function-name and the optional $arity
arguments. This
is an XSLT function, and it is available in both XSLT, XQuery 1.0-ml,
and JavaScript.
The $function-name is a string containing a lexical QName. It may be a name
of a builtin-type, type imported using xsl:import-schema, or an extension
type. This parameter is mandatory. The lexical QName is expanded using the
namespace declarations in scope for the expression. If the lexical QName
is unprefixed, then the standard function namespace is used in the expanded
QName.
function-nameString
If $arity parameter is present, then the function returns true if and only if
the function specified by the first argument has a signature that takes $arity
number of arguments.
arityNumberBoolean