Empty token default values -- core or extension support?

Question

I want to provide a default value for tokens when the value is empty, on a per-use basis -- e.g., something like {contact.first_name?Friend} would print the contact's First Name if it's not empty, otherwise print "Friend".

Rationale update: This would allow non-programmers to easily specify a default value without needing to clutter up the tokens UI.

Existing workarounds for this functionality are more cumbersome than that:

• Dave's blog from version 2.2 uses hooks in an extension to hard-code defaults for specific tokens in all cases.
• This SE answer points out that this can be achieved by enabling Smarty processing and then inserting a few lines -- per token -- of Smarty code into the content.

To avoid double-work and/or undertaking the impossible, I ask:

Has any attempt been made to put such per-use-default-value functionality into CiviCRM core or an extension?

Technical challenges update: Tokens are limited to \w characters, so any plan to use a non-word delimiter like ? will have to involve changes in core, as far as I can see.

Answer 1

First - no need to enable Smarty system-wide to do this. Greetings are always parsed by Smarty - see https://civicrm.org/blog/antrik/getting-started-with-new-name-and-greetings-features-in-45.

Besides that, I think you're one of the leading experts on complex token extensions, since you're the primary author of reltoken. But I don't see why you couldn't do this. hook_civicrm_tokenValues gives you access to the token name for parsing, and there's no requirement that the token be listed with hook_civicrm_tokens. So I'd say go for it.

Note that this is similar but not identical to the free-form relative date work Eileen did: https://github.com/civicrm/civicrm-core/pull/12682.