Re: [Exist-open] external variables passed to trigger

[Jens Ø. P. <oe...@gm...>]

Hi Dmitriy and Adam,

Thanks, I understand.

Having $uri is sufficient, I don't have any special use case, only I prefer to have variables declared and not filled in automagically, that's all. I am not sure that the behind-the-scenes provision of variables is part of the functional paradigm, but I rest my point.

Jens

On 25 Feb 2014, at 13:42, Adam Retter <ad...@ex...> wrote:

>> Thanks, so you do not have to declare $uri - it is passed automatically to triggers like the below?
>> 
>> declare function trigger:after-update-document($uri as xs:anyURI) {
>>    local:logEvent('after', 'update', 'document', $uri)
>> };
> 
> Well each trigger now is just a function call, and you write that function!
> 
>> I assume then that I cannot change the name of this "variable".
> 
> I think you can call the variable whatever you like as long as it
> occurs in the same place with the same arity and type.
> 
>> However, there are external variables declared in controllers. Couldn't we have a
>> 
>>        declare variable $exist:uri external;
>> 
>> in triggers for consistency and for bringing out into the open some of the hidden "magic"?
> 
> Well I do not think that imitating what the controller does makes
> things consistent. Certainly other mechanisms in eXist do other
> things. I am rather trying to get away from a hacky script approach to
> a more functional approach. Writing triggers using the functional
> approach is also much simpler for developers as they do not now need
> to write boilerplate code every time to figure out which even they are
> responding to.
> 
> 
> 
>> Jens
>> 
>> On 25 Feb 2014, at 12:06, Adam Retter <ad...@ex...> wrote:
>> 
>>> To elaborate on what Dmitriy is saying...
>>> 
>>> The design of XQuery triggers significantly changed after eXist 1.4.
>>> 
>>> Previously in 1.4 you wrote an XQuery with external variables and then
>>> switched against those variables in your XQuery code  to determine
>>> which even happened in the database and to what.
>>> 
>>> Since 2.0 you instead implement a specific function in your XQuery,
>>> this function represents a s specific event that occurs in the
>>> database. Your function will be invoked when that even happens, and
>>> the variables that you are looking for are given to you as functions
>>> to the parameter.
>>> 
>>> Hope that helps?
>>> 
>>> On 25 February 2014 10:50, Dmitriy Shabanov <sha...@gm...> wrote:
>>>> 
>>>> 
>>>> 
>>>> On Tue, Feb 25, 2014 at 2:18 PM, Jens Østergaard Petersen
>>>> <oe...@gm...> wrote:
>>>>> 
>>>>> Hi,
>>>>> 
>>>>> I want to write an XQuery trigger that processes a document to be indexed,
>>>>> but I find no information on the external variables available to me to tell
>>>>> the script the URI of the document, etc. I have found some 1.4 triggers that
>>>>> use external exist:* variables, but would like to see the full list of
>>>>> possibilities for version 2.
>>>> 
>>>> 
>>>> not sure what document you mean, but there are xquery function with document
>>>> URI in parameters http://exist-db.org/exist/apps/doc/triggers.xml#D2.2.5.3
>>>> 
>>>> 
>>>> --
>>>> Dmitriy Shabanov
>>>> 
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>>> 
>>> 
>>> 
>>> --
>>> Adam Retter
>>> 
>>> eXist Developer
>>> { United Kingdom }
>>> ad...@ex...
>>> irc://irc.freenode.net/existdb
>> 
> 
> 
> 
> -- 
> Adam Retter
> 
> eXist Developer
> { United Kingdom }
> ad...@ex...
> irc://irc.freenode.net/existdb