8e22084c_Nucleus___Plugin_API_usPlugin__redefinable_methods__Explanation
[Method Signature] doIf($key, $value) [Explanation] 
(v3.30) Evaluates a custom conditional statement for the if/ifnot/elseif/elseifnot skin variables. Must return either true or false. $key and $value are strings passed from the if/ifnot/elseif/elseifnot skin variable. Normally, the plugin should check whether $key has the value of $value, but other uses are possible. Plugins that make use of this method, should document its use for users of the plugin.
Nucleus - Plugin API
Explanation