[DFDL-WG] clarification: fn:exactly-one function

[Mike Beckerle]

According to the DFDL spec, fn:exactly-one returns "True if the provided
sequence contains exactly one node/value," which suggests that the function
would return false if the sequence contains > or < 1 node/value.

The XPath description states that fn:exactly-one "returns $arg if it
contains exactly one item. Otherwise, raises an error."

It seems of value to have a true/false result, because something that
raises an error like this can only be used as an assertion effectively. On
the other hand, that's not what XPath does.


Mike Beckerle | OGF DFDL Workgroup Co-Chair | Tresys Technology |
www.tresys.com
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