Hi, Thanks a lot for the quick fix!
I am not sure I understand the check (when (or (not (string-match-p "[0-9]" value)) (and (string-match-p "[1-9]" value) (= 0 (string-to-number value)))) before the error message. Wouldn't it be good enough to apply the format on the result of string-to-number? This would permit to have markers "TODO" or "XXX" without getting an error. Moreover, the test is wrong for legitimate numbers such as "0e3" while it permits non-numbers such as "1XX". The test is also true if the property is missing, forcing one to add the property everywhere in the file. Hendrik