Passing a variable to template function in org-capture-templates

Question

I'm using org-capture to insert expenses into a Ledger file with this template, along with auto-completion for the various expense categories:

(setq ledger-expense-completions
    (list
     "" ;; needed for first | for mapconcat
     "Expenses:Food" "Expenses:Food:Restaurants" "Expenses:Food:Groceries"
     ))

(setq capture-expense-template
    "%%(org-read-date) * %%^{Description}
  %%^{Expense%s}  %%^{Amount}
  Account:Cash")

(defun return-capture-expense-template () 
    (let ((compstring
        (mapconcat 'identity ledger-expense-completions  "|" )))
            (format capture-expense-template compstring)))

(setq org-capture-templates
    (append '(("l" "Ledger entries")
              ("lc" "Cash" plain
              (file "~/Documents/journal.ledger")
              (function return-capture-expense-template)
              :empty-lines-before 1
              :empty-lines-after 1))
            org-capture-templates))

This works fine, however I'd like to modify return-capture-expense-template to make it a bit more dynamic so that I can pass in the account, e.g., "Account:Bank" or "Account:Cash", to support variations of this template without creating a separate capture-expense-template for each variation.

So here's how I modified things:

(setq ledger-expense-completions
    (list
     "" ;; needed for first | for mapconcat
     "Expenses:Food" "Expenses:Food:Restaurants" "Expenses:Food:Groceries"
     ))

(setq capture-expense-template
    "%%(org-read-date) * %%^{Description}
  %%^{Expense%s}  %%^{Amount}
  %s")


(defun return-capture-expense-template (account) 
    (let ((compstring
        (mapconcat 'identity ledger-expense-completions  "|" )))
            (format capture-expense-template compstring account)))

(setq org-capture-templates nil)
(setq org-capture-templates
    (append '(("l" "Ledger entries")
              ("lc" "Cash" plain
              (file "~/Documents/journal.ledger")
              (function return-capture-expense-template "Account:Bank")
              :empty-lines-before 1
              :empty-lines-after 1))
            org-capture-templates))

When I try evaluating (return-capture-expense-template "Account:Bank") on a separate line, that gives me the template output that I would expect (with "Account:Bank" dynamically inserted into the capture template), however when I run org-capture, I get Wrong number of arguments because the "Account:Bank" is not getting passed to return-capture-expense-template on this line: (function return-capture-expense-template "Account:Bank").

I reviewed the docs for Anonymous Functions and tried writing that line in various ways, but nothing I do seems to be working.

Is it not possible to pass a variable to a function when using the special form function?

Answer 1

You can specify your own properties in the property list for the template, and then you can access those properties with plist-get and org-capture-plist. Here's a brief example:

(defun my/expense-template ()
  (format "Hello world %s" (plist-get org-capture-plist :account)))
(setq org-capture-templates '(("x" "Test entry 1" plain
                               (file "~/tmp/test.txt")
                               (function my/expense-template)
                               :account "Account:Bank")
                              ("y" "Test entry 2" plain
                               (file "~/tmp/test.txt")
                               (function my/expense-template)
                               :account "Account:AnotherBank")))

I hope that helps!

Answer 2

An alternative to Sacha's my/expense-template is:

(defun my/expense-template ()
  (format "Hello world %s" (org-capture-get :account)))

We spare some code by using the org-specialised org-capture-get.