Use ternary operator in freemarker?

If you're using freemarker 2.3.23 or newer, you can use the then built-in:

<a href="${a?then('a.htm','b.html')}" target="${openTarget}">

If you're using an older version of freemarker, you can use instead the string built-in:

<a href="${a?string('a.htm','b.html')}" target="${openTarget}">

When applied to a boolean, the string built-in will act as a ternary operator.

---

If you are using older Freemarker versions before 2.3.23, then you can use this macro which provides a straightforward way to do ternary operations:

<#macro if if then else=""><#if if>${then}<#else>${else}</#if></#macro>

It's easy to use, looks nice and quite readable:

<@if someBoolean "yes" "no"/>

Note that it is @if - and not #if as in the built-in directive. Here are some more examples.

<!-- `else` is optional -->
<@if someBoolean "someBoolean is true"/>  

<!-- expressions -->
<@if (someBoolean||otherBoolean)  "hello,"+user.name  1+2+3 />  

<!-- with parameter names -->
<@if someBoolean then="yes" else="no" />  

<!-- first in list? -->
<#list seq as x>
    <@if (x_index==0)  "first"  "not first"/> 
<#list> 

For some reason you can't add parenthesis around nameless parameters, if they are non-boolean expressions. That could have increased readability even more.