View Template: For Loops

[RichardM]

Okay so there is support for looping over an array but what if you want to loop over say the values 0-10 or all even numbers from 0-100? or possibly even something like for(i=0; i<{{obj.@total}}; i++) ???

I'm thinking about adding this into DooView but I can not settle on a syntax to use and also a way to allow for complex (every even number or other math functions) and also to allow the use of currently running loops so you might have

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<!-- loop users -->
<!-- for:ForLoopName | 0 | < | users' value.@something | ++ -->
{{ForLoopName}}
<!-- if (ForLoopName % 5 == 0) -->
<br />
<!-- endif -->
<!-- endfor -->
<!-- endloop -->


This would become something like

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<?php for ($ForLoopName = 0; $ForLoopName < $v2->something; $ForLoopName++) { ?>
...
<?php } ?>


Any thoughts ???

[leng]

how about:

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<!-- loop 0-100 -->

<span>{{l' v}}</span> (this would be the number)

<!-- endloop -->

to loop to variable

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<!-- loop 0-{{total}} -->

<span>{{l' v}}</span> (this would be the number)

<!-- endloop -->

from and to (both variables)

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<!-- loop {{start}}-{{total}} -->

<span>{{l' v}}</span> (this would be the number)

<!-- endloop -->

[RichardM]

Leng,

I rather like the syntax. My only thought is I want the for loop to be independent of loops used to iterate over array date passed to the templates.

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<!-- for {{start}}-{{total}} -->
<span>{{f' v}}</span> (this would be the number)
<!-- endloop -->


Also slightly off topic but still semi related. You need to be careful of using the l v' v' syntax in examples of the looping as nested loopsonly seem to work properly using the value' and not v' having tested it last night and the only solution i could see was to end up testing for both v' v' and value' value'. Additionally if you choose one method you should stick with it and avoid {{foo' value' v' value' v.@bar}}


Richard

[RichardM]

I'm going to give this a shot with the following syntax

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<!-- for KEY_VAR from KEY_FROM to KEY_TO -->
    {{KEY_VAR}}<br />
<!-- endfor -->


which would be used something like this something like

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<!-- for index from 0 to {{l' v' v.rank}} -->
    <img src="rank_img_part_{{index}}.gif" />
<!-- endfor -->


And possibly an optional part can be added now or later to allow for incrementby???

Richard

[RichardM]

Okay. Got this working for a simple

for (i = from; i < to; i++)

But how do you suggest picking the operator because I can see people wanting to do
for (i = from; i > to; i++)


Richard

[leng]

Best with the operator, familiar to both PHP/JS people and I can do reversed loop with i--

[RichardM]

Right so this is what I have come up with:

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// A simple loop from 0 to 10
<!-- for i from 0 to 10 -->
   {{i}},
<!-- endfor -->
// Renders 0, 1, 2..., 9, 10

// A simple loop from 0 to 10 with steps of 2
<!-- for i from 0 to 10 step 2 -->
   {{i}},
<!-- endfor -->
//Renders 0, 2, 4..., 8, 10

// Counting backwards
<!-- for i from 10 to 0 step 3 -->
   {{i}},
<!-- endfor -->
// Renders 10, 7, 4, 1

// With some data stored in template variables
//$data['someNumberInData'] = 10
<!-- for i from 0 to {{someNumberInData}} -->
   {{i}},
<!-- endfor -->
// Renders 0, 1, 2..., 9, 10

// In loop
<!-- loop users -->
<!-- for i from 0 to {{users' v.@rank}} -->
   {{i}},
<!-- endfor -->
// Assuming 1 user with a rank of 5
// Renders 0, 1, 2, 3, 4, 5


The code it self is compiled down to something along the lines of

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<?php foreach(range(10, 0, 3) as $data['i']): ?>
   <?php echo $data['i']; ?>
<?php endforeach; ?>


So as you can see the variable is stored into the data array. This is for 3 simple reasons:

• You don't have to start the for statement as <!-- for' v' v' to get to a sensible level to use with running for loops
• You can change the value using logic within the for section
  

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  <!-- if ({{i}} == 3) -->
     <!-- set i as 5 -->
<!-- endif -->


• You can nest one for statement inside another
  

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  <!-- for i from 10 to 0 step 3 -->
   <!-- for j from 0 to 10 step 2 -->
      {{i}} : {{j}}
   <!-- endfor -->
<!-- endfor -->


I'll be submitting this shortly


Richard

[RichardM]

I've added some additional functionality to the for command and added a new variable output tag as well. These are used to iterate over 'named' arrays so you can iterate over one array inside another where the second array is not the child to its parent. This works like this:

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<ul>
<!-- for users as user -->
<li>{{$user.@id}} :: {{$user.@name}}</li>
<!-- endfor -->
</ul>


Or if you want to iterate with a key you can do

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<ul>
<!-- for users as user_key=>user -->
<li>{{$user_key}} :: {{$user.@name}}</li>
<!-- endfor -->
</ul>


You can also use the {{$foo}} inside of other tags like

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<!-- if ({{$foo}} == 1) -->
I'm first
<!-- endif -->


Richard

[leng]

that's nice!

[RichardM]

I may extend this shortly so that you can do

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<!-- for $key as subkey=>$subvar -->


The $ in front of the key would let you go into a subloop so you may have

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<!-- for users as user -->
<!-- for $user.@roles -->


or something similar to the above anyways...will provide more info when i come to a decision on this. For now though the key part has no $ at the start and is an identifer to some array in $data. You need to use the <!-- loops to get at sub arrays of a parent.


Richard