You can use the arc:if keyword to evaluate expressions that can contain items, attributes, and values. The scope of the keyword is executed if the specified expression evaluates to true.

Parameters

• exp: The expression to evaluate. You can make string, date, and numeric comparisons.
• attr: The name of the attribute to compare the value of. The value of an attribute can be checked for a matching value or for the values null or notnull.
• value: The value to compare with the value of the attribute specified by attr.
• item: The item that contains the attribute being compared.
• operator: The name of the operator to compare the operands specified by attr and value. Allowed values: null, notnull, hasvalue, equals, equalsignorecase, notequals, lessthan, and greaterthan. Default: notnull.
• action: The action to perform if the expression evaluates to true. Allowed values: break, continue.

Control Attributes

None

Examples

Evaluate a simple comparison of two values:

<arc:if exp="[attr] == 10">

Evaluate the equality of a given value and the value of a given attribute:

<arc:set attr="attr1" value="value1"/>
<arc:set attr="attr2" value="value2"/>
<arc:if attr="attr1" value="[attr2]" operator="notequals"> <!-- Evaluates to true -->
<arc:else>
False
</arc:else>
True
</arc:if>

Evaluate whether an attribute exists:

<arc:set attr="exists" value="true"/>
<arc:if attr="exists"> <!-- Evaluates to true -->
[exists]
</arc:if>

See Also

• arc:exists: Check that an attribute has a value in the specified item.
• arc:equals: Create a block that is executed when equality is met.