[Monetdb-developers] MXQ: MapiClient -lxquery output mode

Fabian Groffen Fabian.Groffen at cwi.nl
Thu Aug 17 22:05:41 CEST 2006

Hi all,

As you may have noticed by now, MapiClient has been changed to act
differently for xquery than it used to before.  I reverted the original
behaviour for greener XQuery pastures, but the change itself is not
done without any doubts from my side.

MapiClient used to report errors in xquery mode in a terse way; it just
reported the error message, without the leading bang (!).  For all other
languages, MapiClient is more verbose: it prints the query being
executed, action taken and the error with leading bangs prefixed with
"ERROR: ".  Niels made xquery behave as all the other languages for
errors for the sake of consistency; a thing I wholeheartedly agree with.
However, some considerable amount of tests in the XQuery testweb has to
be reapproved if this change is put through, which was not done at the
same time of Niels' change.

So far for the history.  Since I'd like to have consistency (agreeing
with Niels), I'd like to see MapiClient reporting errors for xquery in
the verbose way like it does for all other languages.  However, why was
this special mode enabled for xquery in the first place?
My best guess is that because XQuery is non-interactive (through
MapiClient) it makes no sense to print the query upon error, because the
query already is in a file, and it can only contain one, unlike SQL,
where it is nice to know *which* statement was being executed.
Or did somebody just not like MapiClient's error output?

I for one like the more terse error output in a way, and would be in
favour of adding a flag to enable this error reporting.

Here, I'd like to open up the discussion for who thinks that is
necessary.  I go for removing the special error output for xquery and
approving all tests in XQuery testweb that are affected by that change.
With no (negative) response to this message, I will assume this change
is ok with the XQuery people and "implement" this change somewhere next

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