Re: PCM completion word boundaries

[Leo <sdl.web@gmail.com>]

On 2011-08-13 23:18 +0800, Stefan Monnier wrote:
>> The reason I am including > is that in Scheme there are tons of
>> functions with -> in it. > is a bit slower to type and would be great if
>> I can avoid it using completion.
>
> That would make sense, yes, but it would require more changes.  You may
> want to start by looking at completion-pcm--string->pattern.

So it seems completion-pcm--string->pattern needs to handle three cases:

  1.  <word>  any       <delim>
  2.  <delim> any       <delim>
  3.  <delim> any-delim <word>

Case 3 is missing i.e. it should insert delim chars between delim char
and the following word.

How about something along these lines (diff against emacs-23)?


diff --git a/lisp/minibuffer.el b/lisp/minibuffer.el
index 297cecb5..0c08eb33 100644
--- a/lisp/minibuffer.el
+++ b/lisp/minibuffer.el
@@ -1799,7 +1799,7 @@ (defun completion-pcm--pattern-trivial-p (pattern)
 (defun completion-pcm--string->pattern (string &optional point)
   "Split STRING into a pattern.
 A pattern is a list where each element is either a string
-or a symbol chosen among `any', `star', `point'."
+or a symbol chosen among `any', `any-delim', `star', `point'."
   (if (and point (< point (length string)))
       (let ((prefix (substring string 0 point))
             (suffix (substring string point)))
@@ -1824,18 +1824,28 @@ (defun completion-pcm--string->pattern (string &optional point)
         ;; This is determined by the presence of a submatch-1 which delimits
         ;; the prefix.
         (if (match-end 1) (setq p (match-end 1)))
+        (when (and (/= p p0) (not (zerop p0)))
+          (push 'any-delim pattern))
         (push (substring string p0 p) pattern)
+        (when (/= p p0)
+          (push 'any pattern))
         (if (eq (aref string p) ?*)
             (progn
               (push 'star pattern)
               (setq p0 (1+ p)))
-          (push 'any pattern)
+          (when (= p p0)
+            (push 'any pattern))
+          (push (string (aref string p)) pattern)
           (setq p0 p))
+        (incf p0)
         (incf p))
 
+      (when (/= p0 (length string))
+        (push 'any-delim pattern))
+      (push (substring string p0) pattern)
       ;; An empty string might be erroneously added at the beginning.
       ;; It should be avoided properly, but it's so easy to remove it here.
-      (delete "" (nreverse (cons (substring string p0) pattern))))))
+      (delete "" (nreverse pattern)))))
 
 (defun completion-pcm--pattern->regex (pattern &optional group)
   (let ((re
@@ -1846,6 +1856,10 @@ (defun completion-pcm--pattern->regex (pattern &optional group)
                       ((star any point)
                        (if (if (consp group) (memq x group) group)
                            "\\(.*?\\)" ".*?"))
+                      (any-delim
+                       (concat (and group "\\(")
+                               completion-pcm--delim-wild-regex "*"
+                               (and group "\\)")))
                       (t (regexp-quote x))))
                   pattern
                   ""))))