How to resolve a form before use

Question

I have a form variable which contains a list of file paths specified via functions:

(defcustom my-files-form
      '(append (list (concat my-root ".emacs")
                     (concat my-root ".custom"))
               (file-expand-wildcards (concat my-elisp "user-lisp/[a-z]*.el")))
      "My Form"
      :type 'string)

Before I use the form in a tags-search I want to filter the form's file paths by seq-filter (specifically (seq-filter 'file-exists-p my-files-form)).

However I get an error "Wrong type argument: stringp, append" when doing so. I guess this happens because my-files-form is not yet a proper list of paths but the instructions to generate the list of paths.

How can I resolve these instructions into a proper list?

@drew Thanks for hint about the `elisp` tag. (However I feel dumping the URL in the comments section without further remarks is a little bit terse given a community which wants to be friendly...) — halloleo, Oct 15 '22 at 02:54
@phils Works perfectly! Thanks a lot. -- Would you mind turning your comment into an answer? If you mind, I'm happy to do so. — halloleo, Oct 17 '22 at 04:13

score 2 · Accepted Answer · answered Oct 17 '22 at 04:26

(seq-filter 'file-exists-p (eval my-files-form))

Refer to C-hf eval

Also note that variables which are going to be eval'd should have a risky-local-variable property -- but as this happens by default for a variable name ending in -form (amongst other things), you don't need to do anything additional in this instance.

How to resolve a form before use

1 Answers1