Re: C-r and C-s in minibuffer should search completion

[Juri Linkov]

>> Below is a new patch with a small improvement: it introduces a new
>> variable `minibuffer-default-add-p' useful to add more elements to the
>> list of defaults several times in chunks when needed (it can keep the
>> current state of added elements to the list of defaults):
>
> OK, then please remove (make-variable-buffer-local
> 'minibuffer-default-add-function).  And I suggest to change
> minibuffer-default-add-p into minibuffer-default-add-done (and to
> reverse its default to nil).

In the patch below I renamed minibuffer-default-add-p into
minibuffer-default-add-done, changed its default to nil, and
removed make-variable-buffer-local for minibuffer-default-add-function.

Also I moved (setq minibuffer-default-add-done t) to goto-history-element
just before the call to minibuffer-default-add-function, so there is no
need to set this variable to t in minibuffer-default-add-function
explicitly in normal cases.  When necessary, minibuffer-default-add-function
can nullify minibuffer-default-add-done to be able call this function more
than once.

> Also the docstring of minibuffer-default-add-function needs to mention
> that the function should set minibuffer-default-add-done.

minibuffer-default-add-function now doesn't need to set
minibuffer-default-add-done any more, so I updated the
docstrings accordingly.

> This said, I'm wondering when the chunked computation makes sense.
> Do you have an example in mind?

I don't have a concrete example.  When the chunked computation makes
sense, a function defined by minibuffer-default-add-function can use
a new specific global variable that will count the number of
function calls.  But this is not necessary now, and the main thing
I added is the possibility to call this function more than once,
when this functions sets minibuffer-default-add-done to nil.

This patch also changes the error message "End of history; no next item"
to "End of defaults; no next item" for the end of the list of defaults.

Index: lisp/simple.el
===================================================================
RCS file: /sources/emacs/emacs/lisp/simple.el,v
retrieving revision 1.912
diff -c -r1.912 simple.el
*** lisp/simple.el      26 Mar 2008 03:40:40 -0000      1.912
--- lisp/simple.el      27 Mar 2008 23:35:05 -0000
***************
*** 1304,1313 ****
--- 1305,1353 ----
  
  (defvar minibuffer-temporary-goal-position nil)
  
+ (defvar minibuffer-default-add-function 'minibuffer-default-add-completions
+   "Function run by `goto-history-element' before consuming 
`minibuffer-default'.
+ This is useful to dynamically add more elements to the list 
`minibuffer-default'
+ when `goto-history-element' reaches the end of this list.
+ Before calling this function `goto-history-element' sets the variable
+ `minibuffer-default-add-done' to t, so it will call this function only
+ once.  In special cases, when this function needs to be called more
+ than once, it can set `minibuffer-default-add-done' to nil explicitly,
+ overriding the setting of this variable to t in `goto-history-element'.")
+ 
+ (defvar minibuffer-default-add-done nil
+   "When nil, add more elements to the end of the list of default values.
+ The value nil causes `goto-history-element' to add more elements to
+ the list of defaults when it reaches the end of this list.  It does
+ this by calling a function defined by `minibuffer-default-add-function'.")
+ 
+ (make-variable-buffer-local 'minibuffer-default-add-done)
+ 
+ (defun minibuffer-default-add-completions ()
+   "Return a list of all completions without the default value.
+ This function is used to add all elements of the completion table to
+ the end of the list of defaults just after the default value."
+   (interactive)
+   (let ((def minibuffer-default)
+       (all (all-completions ""
+                             minibuffer-completion-table
+                             minibuffer-completion-predicate
+                             t)))
+     (if (listp def)
+       (append def all)
+       (cons def (delete def all)))))
+ 
  (defun goto-history-element (nabs)
    "Puts element of the minibuffer history in the minibuffer.
  The argument NABS specifies the absolute history position."
    (interactive "p")
+   (when (and (not minibuffer-default-add-done)
+            (functionp minibuffer-default-add-function)
+            (< nabs (- (if (listp minibuffer-default)
+                           (length minibuffer-default)
+                         1))))
+     (setq minibuffer-default-add-done t
+         minibuffer-default (funcall minibuffer-default-add-function)))
    (let ((minimum (if minibuffer-default
                     (- (if (listp minibuffer-default)
                            (length minibuffer-default)
***************
*** 1320,1326 ****
              (minibuffer-contents-no-properties)))
      (if (< nabs minimum)
        (if minibuffer-default
!           (error "End of history; no next item")
          (error "End of history; no default available")))
      (if (> nabs (length (symbol-value minibuffer-history-variable)))
        (error "Beginning of history; no preceding item"))
--- 1360,1366 ----
              (minibuffer-contents-no-properties)))
      (if (< nabs minimum)
        (if minibuffer-default
!           (error "End of defaults; no next item")
          (error "End of history; no default available")))
      (if (> nabs (length (symbol-value minibuffer-history-variable)))
        (error "Beginning of history; no preceding item"))

Index: lisp/bindings.el
===================================================================
RCS file: /sources/emacs/emacs/lisp/bindings.el,v
retrieving revision 1.202
diff -c -r1.202 bindings.el
*** lisp/bindings.el    26 Mar 2008 03:32:46 -0000      1.202
--- lisp/bindings.el    27 Mar 2008 23:35:36 -0000
***************
*** 650,656 ****
        "^No later matching history item$"
        "^No earlier matching history item$"
        "^End of history; no default available$"
!       "^End of history; no next item$"
        "^Beginning of history; no preceding item$"
        "^No recursive edit is in progress$"
        "^Changes to be undone are outside visible portion of buffer$"
--- 650,656 ----
        "^No later matching history item$"
        "^No earlier matching history item$"
        "^End of history; no default available$"
!       "^End of defaults; no next item$"
        "^Beginning of history; no preceding item$"
        "^No recursive edit is in progress$"
        "^Changes to be undone are outside visible portion of buffer$"

-- 
Juri Linkov
http://www.jurta.org/emacs/