Enums with variable index

Question

I'm not sure what the correct wording of my question is, but I added an enum (NP_PostTypeType) because I need to know what the type of each item in my initial enum (NP_PostType) is.

I store the current PostType in $postType which gets fed into a method and now in that method I need to extract the type for each type.

What I tried doing was: switch(NP_PostTypeType::$type), but this yields: Fatal error: Access to undeclared static property: NP_PostTypeType::$type

These are my 2 enums:

abstract class NP_PostType extends BasicEnum {
    const Event = "event";
    const Job = "job";
    const Quote = "quote";
    const Status = "status";
    const Video = "video";
}

abstract class NP_PostTypeType extends BasicEnum {
    const Event = "type";
    const Job = "type";
    const Quote = "format";
    const Status = "format";
    const Video = "format";
}

How do I go about this?

Answer 1

You can't access a constant like you do with a static property, the constant function is your solution :

$type = constant('NP_PostTypeType::' . $postType);

But be careful, your $postType case must match your NP_PostTypeType constant names (currently not the case), you should update your NP_PostType class to :

abstract class NP_PostType extends BasicEnum {
    const Event = "Event";
    const Job = "Job";
    const Quote = "Quote";
    const Status = "Status";
    const Video = "Video";
}

Answer 2

Try converting expression to string: switch(constant("NP_PostTypeType::$type"))

Answer 3

Use constant,

$constant = "Event";
$classname = "NP_PostType";
$variable = $classname.'::'.$constant;
echo constant($variable); //event

Working Demo.