Outputting Array elements by index in Store Morph. &mvt:row:cols[g.col]; fails.

[RayYates]

I'm trying to restructure the data from an existing table. I've managed to get the information in an array with this structure l.settings:rows[n]:cols[n]

However &mvt:row:cols[g.col]; causes a runtime error;
Array index must be positive integer

<mvt:assign name="g.col" value="2" />
<mvt:foreach iterator="row" array="rows">
        &mvt:row:cols[1]; | &mvt:row:cols[g.col]; <br>
</mvt:foreach>

What's the workaround? I remember we had this discussion before but can't find it.

[Brennan]

its very un-elegant but this should work. You build the variable as a string value and then use miva_variable_value to evaluate that string as a variable.

<mvt:eval expr="miva_variable_value( 'l.settings:row:col[' $ g.col $ ']' )" />

Long term we have plans to solve this in the template language.

[RayYates]

Thanks Brennan, I should have remembered that.

I ended up using Toolbelts eval function, since it understands variables as array indexes, but yea, it would be nice Store Morph did too. e.g. &mvt:variable[index];

[Kent Multer]

Hi, I'm reopening this thread to address a similar problem. In my case, I need to put the index on the left side of the assignment.

This works:

<mvt:assign name="l.MyArray[123]" value="'XXXXX'" />

But this doesn't:

<mvt:assign name="l.MyArray[l.MyIndex]" value="'XXXXX'" />

I've tried a few different ways to write this, but there doesn't seem to be a way to put an index variable in the destination. Is there a trick I'm not aware of?

Thanks --

[dcarver]

You cannot do it like that, you could do something like this though

<mvt:assgin name="l.MyArray_Size" value="miva_array_insert( l.MyArray, 'XXXXX', l.MyIndex )" />

[Kent Multer]

Hey, clever idea! But it doesn't quite work for my project. I need to insert elements into an array, and also update some of them, during a loop thru the basket contents. And it's a sparse array, indexed by product ID.

Unfortunately, miva_array_insert can only do inserts, not updates. If you call it with an index N, and there's already an element N, the existing element is relocated to N + 1, and higher-numbered elements are also moved up. Similarly, when you remove an array element with miva_array_delete, all the higher-numbered elements' indexes are decreased by 1.

So to update an element, I would have to re-create the entire array every time I update an element, by copying the elements to a new variable and modifying one of them in the process. Between that and the calls to miva_variable_value, this is getting kind of messy ... Looks like the client will need a module for this. Fortunately, the store is already running some custom modules I wrote, so I can just add this feature to one of those.

Thanks for the idea; it may come in handy in the future.

[dcarver]

You could use a combination of miva_array_clear and miva_array_insert. miva_array_clear will delete the elements but not collapse the array.

[Kent Multer]

Thanks, I didn't know about miva_array_clear. But I think I'm still going with a different solution for this project.