plugin value in a template conditional

Question

I've frequently done this with success:

{if '{exp:my_plugin:my_method}'}My method returned true{/if}

Or the opposite also works:

{if '{exp:my_plugin:my_method}' == '0'}My method returned false{/if}

However, doing this for methods with dynamic parameters that also return a string instead of a boolean seems to be impossible - eg (inside of a channel entries tag):

{if '{exp:my_plugin:my_method entry_id="{entry_id}"}' == 'blah'}My method returned the word blah{/if}

Interestingly, calling the plugin outside the conditional at least once in the same template makes the conditional work as expected:

test output: {exp:my_plugin:my_method entry_id="{entry_id}"}
{if '{exp:my_plugin:my_method entry_id="{entry_id}"}' == 'blah'}My method returned the word blah{/if}

... but this is obviously far too weird and fragile to be useful!

Wondering if I'm missing something obvious or making a mistake?

Answer 1

Try by using parse="inward" parameter within the plugin tag like:

{if '{exp:my_plugin:my_method entry_id="{entry_id}" parse="inward"}' == 'blah'}My method returned the word blah{/if}

Answer 2

Digital Surgeons appear to have made a plugin which works around this particular problem:

http://devot-ee.com/add-ons/ifify