Re: [basex-talk] small issue with map:put()

Hi Dirk,

Hmm. Thanks for the reply ( I didn't say: answer ;-)

- Rob

-----Oorspronkelijk bericht----- Van: Dirk Kirsten [mailto:dk@basex.org] Verzonden: vrijdag 21 november 2014 10:02 Aan: Rob Stapper CC: 'BaseX' Onderwerp: Re: [basex-talk] small issue with map:put()

Hi Rob,

to be honest; I don't know. It is part of the XQuery 3.0 spec and I am sure the wise people who have written this spec have a reason to do so. I can think of a number of reasons to always include it: - obviously, you will need it for some functions to identify them , because you could e.g. have two functions with the same name, but different arity. So if you need it for some, it could make sense to make it a requirement for all for consistency - it could be for avoiding errors in the code. Suppose, in your function changes in a nwe version and now needs just one instead of two arguments. With the arity given in a function item, you can detect this at compile time. Without it, it is a runtime issue and potentially much more dangerous. - I guess it is also slightly easier for an implementation to look up the function if the arity is given as well, as it can be a simple hash lookup. Without it, you might need to scan and find the right function. Although, to be honest, I think the overhead is negligible.

But if you really want to know the reasons and not just me thoughts, it might be better to ask on xquery-talk.

Cheers, Dirk

On 11/21/2014 09:08 AM, Rob Stapper wrote:

Hi Dirk,

I have to ask this: What is the "fun" of the function-arity to be a part of its identification. Which means that a property is part of an identification.

• Rob

-----Oorspronkelijk bericht----- Van: Dirk Kirsten [mailto:dk@basex.org] Verzonden: donderdag 20 november 2014 11:14 Aan: Rob Stapper CC: BaseX Onderwerp: Re: [basex-talk] small issue with map:put()

Hello Rob,

I have to admit this error message is not really helpful at all, but you are missing the arity. It should be

let $d := $c( $b, map:put#3)

i.e. you always have to give the artiy of the function if you want to get the function item.

Cheers, Dirk

On 11/20/2014 11:00 AM, Rob Stapper wrote:

...

Hi,

See attached snippet.

I get the error-message: no context value bound, on this one.

What's going wrong here?

Rob

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