Fluid Syntax: Conditions & Booleans

Boolean conditions

Boolean conditions are expressions that evaluate to true or false.

Boolean conditions can be used as ViewHelper arguments, whenever the datatype boolean is given, e.g. in the condition argument of the <f:if> ViewHelper.

1. The expression can be a variable, which is evaluated as follows:

   • Number: Evaluates to true if it is not 0.
   • Array: Evaluates to true if it contains at least one element.

2. The expression can be a statement consisting of: term1 operator term2, for example {variable} > 3.

   • The operator can be one of the following: >, >=, <, <=, ==, ===, !=, !==, or %.
3. The previous expressions can be combined with || (logical OR) or && (logical AND).

Examples:

<f:if condition="{myObject}">
  ...
</f:if>

<f:if condition="{myNumber} > 3 || {otherNumber} || {somethingElse}">
   <f:then>
      ...
   </f:then>
   <f:else>
      ...
   </f:else>
</f:if>

<my:custom showLabel="{myString} === 'something'">
  ...
</my:custom>

Example using the inline notation:

<div class="{f:if(condition: blog.posts, then: 'blogPostsAvailable', else: 'noPosts')}">
  ...
</div>

Boolean literals

You can use the boolean literals {true} and {false} in ViewHelper calls. This works both in tag and inline syntax:

<f:render section="MySection" optional="{true}" />

{f:render(section: 'MySection', optional: true)}

If a ViewHelper argument is defined as boolean, it is also possible to provide values of different types, which will then be implicitly converted to a boolean:

<f:render section="MySection" optional="1" />

This can be used to remain compatible to Fluid 2, which did not support boolean literals in all cases.