Low Events: How can I compare formatted start_date and end_date in conditionals?

Question

I've just started using Low Events after realizing the hard way why I need it. I'm attempting to format a nice string when the range happens within the same month; instead of August 14, 2013 - August 16, 2013, I'd like to display August 14-16, 2013.

I've attempted to compare formatted output of the month and year only, like this...

 {if '{event_dates:start_date format="%F%Y"}' == '{event_dates:end_date format="%F%Y"}'}    
      {event_dates:start_date format="%F %j"}-{event_dates:end_date format="%j, %Y"}
 {if:else}          
      {event_dates:start_date format="%F %j, %Y"} - {event_dates:end_date format="%F %j, %Y"}
 {/if}

...yet instead of the expected output EE just complains that it choked on the conditional:

 Parse error: syntax error, unexpected T_STRING in /var/www/vhosts/foo.com/httpdocs/system/expressionengine/libraries/Functions.php(683) : eval()'d code on line 56

Using parse="inward" had no effect, and I've isolated that first {if conditional as the problem. Is there any way to achieve the formatting I'd like without relying on an embedded template?

I also tried swapping the single and double quotes as Robson suggested, but that had no effect.

This is EE 2.5.5 and Low Events 1.1.4, and swapping {exp:channel:entries} for {exp:low_events:entries} makes no difference.

Here's the entire (simplified) template for context:

 {exp:channel:entries channel="events" limit="1" url_title="{segment_2}"}
 {embed="parts/.header" page_title="{title}"}

 <div id="content">
    <h3>{if '{event_dates:all_day}' == 'y'}
            {if '{event_dates:one_day}' == 'y'}
                {event_dates:start_date format="%F %j, %Y"}
            {if:else}
                {if '{event_date:start_date format="%F%Y"}' == '{event_date:end_date format="%F%Y"}'}   
                    {event_dates:start_date format="%F %j"}-{event_dates:end_date format="%j, %Y"}
                {if:else}           
                    {event_dates:start_date format="%F %j, %Y"} - {event_dates:end_date format="%F %j, %Y"}
                {/if}
            {/if}
        {if:elseif '{event_dates:one_day}' == 'y'}
            {event_dates:start_date format="%F %j, %Y"} - {event_dates:start_time format="%g:%i%a"}-{event_dates:end_time format="%g:%i%a"}
        {if:else}
            {event_dates:start_date format="%F %d, %Y"} - {event_dates:start_time format="%g:%i%a"} to {event_dates:end_date format="%F %d, %Y"} - {event_dates:end_time format="%g:%i%a"}
        {/if}
        {if event_location}
        <br/>{event_location}
        {/if}
    </h3>

    <hr/>

    {event_description}

    {if event_rsvp_link}
        <div class="rsvp"><a href="{exp:extract_url}{event_rsvp_link}{/exp:extract_url}">RSVP Now &raquo;</a></div>     
    {/if}

 </div>

 {if no_results}{redirect="404"}{/if}{/exp:channel:entries}
 {embed="parts/.footer"}

Answer 1

To be on the safe side, I'd check for numerical values only, like 201308. Something like this:

{if {event_dates:start_date format="%Y%m"} == {event_dates:end_date format="%Y%m"}}
  same month
{if:else}
  not same month
{/if}

When debugging the advanced conditionals, try to remove them and add them one at a time to see which actual one is causing the trouble.

Answer 2

I guess you should to use exp:low_events:entries instead of exp:channel:entries.