[FEATURE] A new <f:contains> ViewHelper should be added to Fluid (#1125)

[staatzstreich]

A new <f:contains> ViewHelper should be added to Fluid, which checks if a provided value either exists in the provided array or in the provided string. If both the array and the string are provided, an exception should be thrown. This ViewHelper extends the AbstractConditionViewHelper.

Arguments:

mixed $value (needs to be scalar if f:contains is used with the string argument)
array $array
string $string
See also the php in_array() and the php str_contains() functions.

Examples:

<f:contains value="foo" array="{myArray}">

</f:contains>
<f:contains value="foo" string="{myString}">

</f:contains>

<f:variable name="result" value="{f:contains(value: 'foo', array: myArray)}" />

[mbrodala]

I wonder if we should consider extending conditions instead, e.g. using Symfony EL:

{myString contains "foo"}

Then we'd not need to add a viewhelper for each and every bit of functionality.

[s2b]

@mbrodala I agree that we should improve conditions overall. However, in the short term it's probably wise to add ViewHelpers for the most common use cases nonetheless. Also, the following syntax is already possible:

<f:if condition="{f:contains(value: 'foo', array: myArray)} && ...">

[s2b]

The more I think about it, the more I struggle with the VH API. I'm open to other suggestions, but these come to mind:

• Allow both array and string as one argument and differentiate in the VH based on the type
• Split into two: f:contains for strings and f:in for arrays

What do you think?