diff options
Diffstat (limited to 'lisp/format-spec.el')
| -rw-r--r-- | lisp/format-spec.el | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/lisp/format-spec.el b/lisp/format-spec.el index 45c19aebc8b..60ff9f90864 100644 --- a/lisp/format-spec.el +++ b/lisp/format-spec.el @@ -59,6 +59,18 @@ value associated with ?b in SPECIFICATION, either padding it with leading zeros or truncating leading characters until it's ten characters wide\". +the substitution for a specification character can also be a +function, taking no arguments and returning a string to be used +for the replacement. It will only be called if FORMAT uses that +character. For example: + + (format-spec \"%n\" + \\=`((?n . ,(lambda () + (read-number \"Number: \"))))) + +Note that it is best to make sure the function is not quoted, +like above, so that it is compiled by the byte-compiler. + Any text properties of FORMAT are copied to the result, with any text properties of a %-spec itself copied to its substitution. @@ -94,14 +106,15 @@ is returned, where each format spec is its own element." (width (match-string 2)) (trunc (match-string 3)) (char (string-to-char (match-string 4))) - (text (assq char specification))) + (text (let ((res (cdr (assq char specification)))) + (if (functionp res) (funcall res) res)))) (when (and split (not (= (1- beg) split-start))) (push (buffer-substring split-start (1- beg)) split-result)) (cond (text ;; Handle flags. (setq text (format-spec--do-flags - (format "%s" (cdr text)) + (format "%s" text) (format-spec--parse-flags flags) (and width (string-to-number width)) (and trunc (car (read-from-string trunc 1))))) |