[xquery-talk] incorrect syntax?

[Ronald Bourret]

This is actually very straightforward. "return" is a keyword, used in 
FLWOR expressions and a few other places. There is no standalone 
"return" in XQuery. Thus:

    let $x:=0 return (23)

is a valid (if uninteresting) FLWOR expression that is equivalent to the 
even less interesting (but still valid) expression:

    (23)

And a standalone "return" is illegal:

    return (23) (: error :)

Where you have included parentheses below, you are calling a function 
named "return" and XQuery works as expected. It's a bad idea to name a 
function using a keyword as a name, but XQuery allows it. If you replace 
"return(...)" with "foo(...)" in the expressions below, the intended 
meaning will be clear.

The last two XQuery expressions should return errors (and do in the 
online Zorba XQuery processor I tried them in). As noted above, this is 
because there is no standalone use of the "return" keyword -- either the 
processor you are using has a bug or you haven't shown us the entire 
expression.

Thanks,

-- Ron

On 10/1/2012 5:34 PM, Michael Sokolov wrote:
> On 10/1/2012 10:48 AM, Michael Kay wrote:
>> There is no function called "return". Just remove the keyword.
>> Depending on the context, you might need to remove the outer curly
>> braces as well.
>>
>> It's a little confusing because you can say
>>
>> let $x:=0 return 23
>>
>> but you can't say
>>
>> return 23
>
> Actually if you really start to dig, it becomes a lot confusing
>
> you can say
>
> let $x := 0 return (23)
>
> but in that instance return is not a function call; the parentheses here
> are constructing a sequence (of one item)
>
> But if you say
>
> declare default function namespace "x";
> declare function return ($x) { $x+1 };
> return (23)
>
> that does seem to return 24 for at least one processor that I tried,
> which seems truly bizarre (to me, anyway)
>
> yet
>
> declare default function namespace "x";
> declare function return ($x) { $x+1 };
> return 23
>
> returns 23
>
> while
>
> declare default function namespace "x";
> declare function return ($x) { $x+1 };
> return return(23)
>
> returns 24
>
> -Mike Sokolov
>
>
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