Allow using callables as a value for fields

[hackeresq]

This allows the use of a callable as a value for merged fields. For example in your PHP code:

$TBS->MergeField('callable_field', fn() => Carbon::now()->addMonths(12)->toDateString());

Then in your HTML template you can use merge field like [callable_field], which would resolve the callable to a string.

This is useful when you have many "magic fields" that require evaluating a callable. In my case, I have "magic links" that can be generated and included in the template (e.g. one time use login links). I don't want to process those methods every time I merge a doc, rather, this dynamically calls the method just in time.

[hackeresq]

@Skrol29 curious whether this is something that fits within TBS?

[Skrol29]

Hello @hackerESQ ,

Thanks for your Pull Request, Sorry for having been long to reply.

The feature is quite interesting, it is useful for Closure functions, but also for invokable Objects (having a magic __invoke function ). Nevertheless, the implementation is not at the right place according to me. The purpose of meth_Misc_ToStr() is to ensure that the final item value is a string. While your feature should be, I think, to support callable objects, even if i returns another object, or an array, or other...

For example: [callable_field.my_key] should work if your Closure function returns an array such as ['my_key' => 29].

According to me, the place should be at the beginning of meth_Locator_Replace(), shortly after } elseif (is_object($Value)) {

I've not tested yet, but it seems good. I also have to check if the feature is compliant with the security methods_allowed option.

Would you like to change the Pull Request? Or I can do it for the next release.

Regards,

[hackeresq]

@Skrol29 , tinkered with this a bit more, but wasn't able to succeed with your suggestion. Happy to update the PR myself, but I'm definitely stuck.

Would appreciate any further suggestions.

[hackeresq]

@Skrol29 Are you able to guide me a bit more. Happy to help move this to the right place in the class.