0

knowing community,

I want to achieve the following in short: I have a XML-file with listed pizzas inside of it (it is a kind of test file). My page has a select menu from which a user choses one pizza and the pizza size, which is then both displayed below. The content will only show up after the user has chosen. This is the function:

declare function app:showpizza2($node as node(), $model as map(*)){

    let $pizza1 := request:get-parameter('selectMenu1', '')
    let $size1 := request:get-parameter('size1', '')
    return

    for $pizza in $app:pizza//pizza
    where $pizza/@id eq $pizza1
    let $id := $pizza/@id
    return

    (<a data-key="{ $id }" class="person"><div>{ $pizza1 }</div></a>,
    <div>{ $size1 }</div>)    
};

With a second function I now want to build previous/next buttons which take the current shown pizza, find it inside of the XML tree and then go one step further up or down. So far I am able to show one pizza above or below with these lines: 

declare function app:previousPizza($node as node(), $model as map(*)){

    let $pizza1 := request:get-parameter('selectMenu1', '')
    return 

    for $pizza in $app:pizza//pizza
    where $pizza/@id eq $pizza1
    let $previousPizza := $pizza/preceding::pizza[1]
    return 

        <p>{ $previousPizza }</p>
};

The problem of course is that as a "current pizza parameter" I only take the user-chosen value from the select menu. So I guess this is a typical recursion problem because I want to have a function which always takes the current parameter after clicking on a button but I kind of really have no idea how to achieve this. Can you help out?

This is my html-file where I call these functions:

<div class="row">
    <div class="col-sm-4">        
        <!-- form for choosing pizza -->
        <form action="?">                   
            <!-- select Pizza type -->
            <select name="selectMenu1" id="pizzamenu1" 
                data-placeholder="Pizza wählen" style="width:150px">
                <option value=""></option>
                <option value="pizza1">Pizza 1</option>
                <option value="pizza2">Pizza 2</option>
                <option value="pizza3">Pizza 3</option>
            </select>              
            <!-- select pizza size -->
            <select name="size1" data-placeholder="Größe wählen"
                style="width:150px;" onchange="this.form.submit()">
                <option value=""></option>
                <option value="family">Familien Pizza</option>
                <option value="medium">Mittel Pizza</option>
                <option value="small">Kleine Pizza</option>
            </select>
        </form>
    </div>
</div>

<div class="row">
    <div class="col-sm-4">              
        <!-- showpizza2 returns chosen pizza from select menu -->
        <div data-template="app:showpizza2"/>             
        <!-- Show previous pizza -->
        <div data-template="app:previousPizza"/>
    </div>
</div>

Thanks.

dmnk.h
  • 25
  • 5
  • I take it you’re using eXist’s HTML templating module? – Joe Wicentowski Oct 23 '18 at 12:37
  • @joewiz yes, I do :) – dmnk.h Oct 24 '18 at 08:41
  • Okay, one more question to help clarify. Your code looks to me like it should work: once the user selects a pizza (from the select dropdown) and submits the query, both functions should retrieve the `selectMenu1` parameter and allow you to look up the current and preceding pizza and display the respective information. What is the problem then? Are you seeing incorrect information, or are you getting an error? – Joe Wicentowski Oct 24 '18 at 13:01
  • It does what it should at this point, yes - but what I actually want is that I can push the button repeatedly - like scrolling through a book, you know? And always getting the pizza before the pizza before the pizza... this code only shows me ONE pizza before the chosen pizza. – dmnk.h Oct 26 '18 at 10:40
  • What do you mean "always getting the pizza before the pizza before the pizza"? The code for retrieving the "previous" is actually skipping the previous and getting the 2nd previous pizzas? – Joe Wicentowski Oct 27 '18 at 15:45
  • I have a set of pizzas, a list. I have a select menu in which I can select a pizza. And after choosing I want to be able to click through the pizza list, forward or backward, by clicking on a button. Right now I cannot click through the whole list, I will just receive one item. Does that help? – dmnk.h Oct 30 '18 at 08:46

1 Answers1

0

Since the value of the user-selected pizza comes from the html list, it is in $model. Your Xquery function for the next/prev buttons should access the $model to start where you want to.

We would need to see how you call the xquery modules in your .html files, to give you a working code sample. But the problems you describe are likely originating there.

See the documentation for Using the Model to Keep Application Data

duncdrum
  • 723
  • 5
  • 13
  • Thank you @duncdrum I checked your link and this is indeed very helpful, I learn something new here. I guess something nested is needed here, yes. I added my html-code to the post. Thanks a lot, really. – dmnk.h Oct 30 '18 at 12:50