Allow head-hint to be dynamic

Instead of only a string like before, the head-hint can be anything that evaluates to a string. Example: (defhydra hydra-test (:columns 2) "Test" ("j" next-line (format-time-string "%H:%M:%S" (current-time))) ("k" previous-line (format-time-string "%H:%M:%S" (current-time))) ("h" backward-char (format-time-string "%H:%M:%S" (current-time))) ("l" forward-char (format-time-string "%H:%M:%S" (current-time)))) Pressing "hjkl" will refresh the hint, and thus update the current time. Note that the hint needs to evaluate to a string at both compile-time and run-time. The column formatting depends on the compile-time result. Fixes #160
11 years ago · 9f5f089af4
parent 0712176e9b
commit 9f5f089af4
1 changed files with 54 additions and 38 deletions
--- a/hydra.el
+++ b/hydra.el
@ -452,6 +452,11 @@ Return DEFAULT if PROP is not in H."
  (format (format "%%%ds: %%%ds" key-width (- -1 doc-width))
          key doc))

+(defun hydra--to-string (x)
+  (if (stringp x)
+      x
+    (eval x)))
+
 (defun hydra--hint (body heads)
  "Generate a hint for the echo area.
 BODY, and HEADS are parameters to `defhydra'."
@ -467,41 +472,48 @@ BODY, and HEADS are parameters to `defhydra'."
             (cons (cadr h)
                   (cons pstr (cl-caddr h)))
             alist)))))
-
    (let ((keys (nreverse (mapcar #'cdr alist)))
-          (n-cols (plist-get (cddr body) :columns)))
-      (if n-cols
-          (let ((n-rows (1+ (/ (length keys) n-cols)))
-                (max-key-len (apply #'max (mapcar (lambda (x) (length (car x))) keys)))
-                (max-doc-len (apply #'max (mapcar (lambda (x) (length (cdr x))) keys))))
-            (concat
-             "\n"
-             (mapconcat #'identity
-                        (mapcar
-                         (lambda (x)
-                           (mapconcat
-                            (lambda (y)
-                              (and y
-                                   (funcall hydra-key-doc-function
-                                            (car y)
-                                            max-key-len
-                                            (cdr y)
-                                            max-doc-len))) x ""))
-                         (hydra--matrix keys n-cols n-rows))
-                        "\n")))
-
-
-        (concat
-         (mapconcat
-          (lambda (x)
-            (format
-             (if (> (length (cdr x)) 0)
-                 (concat hydra-head-format (cdr x))
-               "%s")
-             (car x)))
-          keys
-          ", ")
-         (if keys "." ""))))))
+          (n-cols (plist-get (cddr body) :columns))
+          res)
+      (setq res
+            (if n-cols
+                (let ((n-rows (1+ (/ (length keys) n-cols)))
+                      (max-key-len (apply #'max (mapcar (lambda (x) (length (car x))) keys)))
+                      (max-doc-len (apply #'max (mapcar (lambda (x)
+                                                          (length (hydra--to-string (cdr x)))) keys))))
+                  `(concat
+                    "\n"
+                    (mapconcat #'identity
+                               (mapcar
+                                (lambda (x)
+                                  (mapconcat
+                                   (lambda (y)
+                                     (and y
+                                          (funcall hydra-key-doc-function
+                                                   (car y)
+                                                   ,max-key-len
+                                                   (hydra--to-string (cdr y))
+                                                   ,max-doc-len))) x ""))
+                                ',(hydra--matrix keys n-cols n-rows))
+                               "\n")))
+
+
+              `(concat
+                (mapconcat
+                 (lambda (x)
+                   (let ((str (hydra--to-string (cdr x))))
+                     (format
+                      (if (> (length str) 0)
+                          (concat hydra-head-format str)
+                        "%s")
+                      (car x))))
+                 ',keys
+                 ", ")
+                ,(if keys "." ""))))
+      (if (cl-every #'stringp
+                    (mapcar 'cddr alist))
+          (eval res)
+        res))))

 (defvar hydra-fontify-head-function nil
  "Possible replacement for `hydra-fontify-head-default'.")
@ -612,11 +624,14 @@ The expressions can be auto-expanded according to NAME."
    (if (eq ?\n (aref docstring 0))
        `(concat (format ,(substring docstring 1) ,@(nreverse varlist))
                 ,rest)
-      `(format ,(replace-regexp-in-string
+      (let ((r `(replace-regexp-in-string
                 " +$" ""
-                 (concat docstring ": "
+                 (concat ,docstring ": "
                         (replace-regexp-in-string
-                          "\\(%\\)" "\\1\\1" rest)))))))
+                          "\\(%\\)" "\\1\\1" ,rest)))))
+        (if (stringp rest)
+            `(format ,(eval r))
+          `(format ,r))))))

 (defun hydra--complain (format-string &rest args)
  "Forward to (`message' FORMAT-STRING ARGS) unless `hydra-verbose' is nil."
@ -964,7 +979,8 @@ result of `defhydra'."
                  (t
                   (let ((hint (cl-caddr h)))
                     (unless (or (null hint)
-                                 (stringp hint))
+                                 (stringp hint)
+                                 (stringp (eval hint)))
                       (setcdr (cdr h) (cons
                                        (hydra-plist-get-default body-plist :hint "")
                                        (cddr h)))))