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I think this has been batted around here before, but would somebody mind
refreshing us as to whether there is any good reason plain {} doesn't
generate () (an empty sequence)?
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If you want historical rationality you will have to ask someone else.
If you want deductive logic ...
{ expr } parses expr ... it returns whatever expr is. If there is nothing
there then thats nothing. () is not nothing, its something. So it would be
silly and inconsistent if {} produced something rather than nothing.
The only time that I can see that it is actually inconvenient ("annoying"?)
that {} produces nothing rather then something is in this particular case with
comments embedded
within literal constructors. Buy why single out () as the something it should
produce ? There is nothing special about the empty sequence that makes it the
best candidate for a fillin for nothing.
Also there is the other use of {} which is in functions
declare function x () { };
Which is rightfully an error because there is no expression and should be.
Although one could argue that it should be treated as
declare function x () { ()};
But then one could argue that in C
foo() { }
should be treated as
foo() { return NULL ; }
But that would be silly now wouldn't it ?
In the end I am not going to try to justify this rule in XQuery ... it just is
the way it is.
-----------------------------------------------------------------------------
David Lee
Lead Engineer
MarkLogic Corporation
[email protected]
Phone: +1 812-482-5224
Cell: +1 812-630-7622
www.marklogic.com
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