Use variable filename for remember template?

[Nathan Neff <nathan.neff@gmail.com>]

Hello,

I am able to successfully read the contents of
"/Users/nate/personal/booktemp.txt" into a new remember-note.

(setq org-remember-templates
     '(("Book" ?b "\n* %^{Book Title} %t :READING:
\n%[/Users/nate/personal/booktemp.txt]\n"
              "L:journal.org")
      ))

Now, I'd like to be able to specify an environment variable like $HOME
instead of /Users/nate.

I'm a lisp beginner, and have tried something like

(setq personal-home-dir (getenv "HOME"))

(setq org-remember-templates
     '(("Book" ?b (concat "\n* %^{Book Title} %t :READING: \n%["
personal-home-dir "/personal/booktemp.txt]\n")
              "L:journal.org")
      ))

but I keep getting "Wrong type argument char-or-string-p" errors.

I'm guessing that the org-remember-templates function wants something
other than a string, but I don't know
where to go from here.

Any help is appreciated.

Thanks,
-Nate