dooviewbasic cycle

[ximian]

Hi,

Sometimes we need to cycle some values inside a for loop. Imagine a simple example where we output a table:

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{% for table as row .. %}
<tr bgcolor="#eeeeee">
   <td>{{row.id}}</td>
</tr>
{% endfor %}

Most of time, designers want to alternate colors, class names, and so on inside the loop.. and this is a standard way of doing things.. nothing special here.
Some template engines have this task much easier to handle.
What do you think of a new tag for this eg: cycle?

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{% cycle ['#eeeeee','#d0d0d0'] %}

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{% for table as row .. %}
<tr bgcolor="{% cycle ['#eeeeee','#d0d0d0'] %}">
   <td>{{row.id}}</td>
</tr>
{% endfor %}

so this become:

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<tr bgcolor="#eeeeee">
   <td>1</td>
</tr>
<tr bgcolor="#d0d0d0">
   <td>2</td>
</tr>
<tr bgcolor="#eeeeee">
   <td>3</td>
</tr>


Well, how can this be implemented? What do you think about a global doo for variable, so that tag

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{% cycle ['#eeeeee','#d0d0d0'] %}

can be rendered as something like

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<?php if( ! isset($data['doo']['cycle']['cid'])){
         $data['doo']['cycle']['cid'] = array('#eeeeee','#d0d0d0');
         end($data['doo']['cycle']['cid']);
      };
      if( next( $data['doo']['cycle']['cid'] ) == false ) print reset($data['doo']['cycle']['cid']);
      else print current($data['doo']['cycle']['cid']) );
?>

where cid is a generated id on rendering process.

What do you think?

Francisco A

[RichardM]

Hey,

Why not just use the new filters?

In template tags define a function as follows:

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public static function filter_cycle(&$num, &$options) {
   return $options[$num % count($options)];
}


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{% set colours as ['#f00', '#0f0', '#00f'] %}
{% for x from 1 to 10 %}
<span style="color:{{x|cycle(colours)}}">Value {{x}}</span><br />
{% endfor %}
<hr />
{% for y from 1 to 10 with meta %}
<span style="color:{{doo.for.y.index|cycle(colours)}}">Value {{y}}</span><br />
{% endfor %}


Note the second example uses the meta data to give us the index value for each looped element as we can not garantee that y would increment by one each time. For example try:

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{% for z from 1 to 10 step 3 %}
<span style="color:{{z|cycle(colours)}}">Value {{z}}</span><br />
{% endfor %}


And they will all be green


Richard

[ximian]

Why not just use the new filters?

Cycle should be independent of for loop. On examples, you are looping colors array, not the data array.. and using a filter we need to change a dummy or reference value.. and be assigning that with for meta becomes difficult to read.

On my previous example, we only need a single line and that's it.. no additional loops.. just a simple line

Francisco A

[ximian]

Richard,

Do you see any problem adding the cycle tag?

Francisco A

[RichardM]

I never added another loop to the example you gave. Also your examples do have loops in them...otherwise if your hard coding say an entire table just add the css styles in manually when you write it. Taking your example and assuming the filter I suggested is defined you can simply write:

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{% set colours as ['#eeeeee','#d0d0d0'] %}
{% for table as row with meta %}
<tr bgcolor="{{doo.for.row.index|cycle(colours)}}">
   <td>{{row.id}}</td>
</tr>
{% endfor %}


OR

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{% for table as row with meta %}
<tr bgcolor="{{doo.for.row.index|cycle(['#eeeeee','#d0d0d0'])}}">
   <td>{{row.id}}</td>
</tr>
{% endfor %}


I'll see about writing a block for it but I may well move the assignment of the array to the top of the compiled code so it does not have to keep checking if its been assigned as the cycle's code is ONLY of any use within a for loop. For now though the filter option I have suggested can/will do the same thing until I get such a tag added.


Richard

[ximian]

Well, i prefer to wait then. This is not critical at all and can wait. I really prefer a cleaner syntax.

Francisco A

[RichardM]

Hi,

This has now been added. Will upload the revised code shortly...just working to add the 'insert' tag while I'm at it.

Usage information can be found here: viewtopic.php?f=7&t=1015&p=4388#p4388


Richard