On 12/21/2012 09:32 AM, David Lee wrote:
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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.
Actually I think () is the closest we have to null and void in xquery,
so it seems consistent and logical to me :)
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 () { ()};
Yes I would
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 ?
Actually my compiler allows "void foo () { }" - why not? A function
that does nothing could be very useful sometimes. "foo () { }" is bad
because implicitly it is declared as returning int, yet does not return
anything.
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