Re: PATCH: Re: insert-last-word/copy-prev-word/... question

[Peter Stephenson <pws@xxxxxxx>]

Peter Stephenson wrote:
> I may present a more complete solution when I've looked at that.

It does appear Sven has done all the hard work, so I could have waited.

The following looks like a reasonably complete solution, even if it
needs tweaking, so I'll commit it unless anyone screams soon.
copy-earlier-word should do essentially what Dominik was asking for.

I think there was a bug with lines containing unusual characters, which
I've avoided by keeping the length of the word we remembered from the
previous invocation.

Index: Src/Zle/zle_hist.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/Zle/zle_hist.c,v
retrieving revision 1.6
diff -u -r1.6 zle_hist.c
--- Src/Zle/zle_hist.c	17 Sep 2001 18:30:49 -0000	1.6
+++ Src/Zle/zle_hist.c	5 Mar 2002 16:15:57 -0000
@@ -410,46 +410,138 @@
 int
 insertlastword(char **args)
 {
-    int n;
+    int n, nwords, histstep = -1, wordpos = 0, deleteword = 0;
     char *s, *t;
-    Histent he;
+    Histent he = NULL;
+    LinkList l = NULL;
+    LinkNode node;
 
-/* multiple calls will now search back through the history, pem */
     static char *lastinsert;
-    static int lasthist, lastpos;
-    int evhist = addhistnum(curhist, -1, HIST_FOREIGN), save;
+    static int lasthist, lastpos, lastlen;
+    int evhist, save;
 
-    if (lastinsert) {
-	int lastlen = ztrlen(lastinsert);
-	int pos = cs;
+    /*
+     * If we have at least one argument, the first is the history
+     * step.  The default is -1 (go back).  Repeated calls take
+     * a step in this direction.  A value of 0 is allowed and doesn't
+     * move the line.
+     *
+     * If we have two arguments, the second is the position of
+     * the word to extract, 1..N.  The default is to use the
+     * numeric argument, or the last word if that is not set.
+     *
+     * If we have three arguments, we reset the history pointer to
+     * the current history event before applying the history step.
+     */
+    if (*args)
+    {
+	histstep = (int)zstrtol(*args, NULL, 10);
+	if (*++args)
+	{
+	    wordpos = (int)zstrtol(*args, NULL, 10);
+	    if (*++args)
+		lasthist = curhist;
+	}
+    }
+
+    if (lastinsert && lastlen &&
+	lastpos <= cs &&
+	lastlen == cs - lastpos &&
+	memcmp(lastinsert, (char *)&line[lastpos], lastlen) == 0)
+	deleteword = 1;
+    else
+	lasthist = curhist;
+    evhist = histstep ? addhistnum(lasthist, histstep, HIST_FOREIGN) :
+	lasthist;
 
-	if (lastpos <= pos &&
-	    lastlen == pos - lastpos &&
-	    memcmp(lastinsert, (char *)&line[lastpos], lastlen) == 0) {
-	    evhist = addhistnum(lasthist, -1, HIST_FOREIGN);
+    if (evhist == curhist) {
+	/*
+	 * The line we are currently editing.  If we are going to
+	 * replace an existing word, delete the old one now to avoid
+	 * confusion.
+	 */
+	if (deleteword) {
+	    int pos = cs;
 	    cs = lastpos;
 	    foredel(pos - cs);
+	    /*
+	     * Mark that this has been deleted.
+	     * For consistency with history lines, we really ought to
+	     * insert it back if the current command later fails. But
+	     * - we can't be bothered
+	     * - the problem that this can screw up going to other
+	     *   lines in the history because we don't update
+	     *   the history line isn't really relevant
+	     * - you can see what you're copying, dammit, so you
+	     *   shouldn't make errors.
+	     * Of course, I could have implemented it in the time
+	     * it took to say why I haven't.
+	     */
+	    deleteword = 0;
 	}
-	zsfree(lastinsert);
-	lastinsert = NULL;
+	/*
+	 * Can only happen fail if the line is empty, I hope.
+	 * In that case, we don't need to worry about restoring
+	 * a deleted word, because that can only have come
+	 * from a non-empty line.  I think.
+	 */
+	if (!(l = bufferwords(NULL, NULL, NULL)))
+	    return 1;
+	nwords = countlinknodes(l);
+    } else {
+	/* Some stored line. */
+	if (!(he = quietgethist(evhist)) || !he->nwords)
+	    return 1;
+	nwords = he->nwords;
     }
-    if (!(he = quietgethist(evhist)) || !he->nwords)
-	return 1;
-    if (zmult > 0) {
-	n = he->nwords - (zmult - 1);
+    if (wordpos) {
+	n = (wordpos > 0) ? wordpos : nwords + wordpos + 1;
+    } else if (zmult > 0) {
+	n = nwords - (zmult - 1);
     } else {
 	n = 1 - zmult;
     }
-    if (n < 1 || n > he->nwords)
+    if (n < 1 || n > nwords) {
+	/*
+	 * We can't put in the requested word, but we did find the
+	 * history entry, so we remember the position in the history
+	 * list.  This avoids getting stuck on a history line with
+	 * fewer words than expected.  The cursor location cs
+	 * has not changed, and lastinsert is still valid.
+	 */
+	lasthist = evhist;
 	return 1;
-    s = he->text + he->words[2*n-2];
-    t = he->text + he->words[2*n-1];
+    }
+    /*
+     * Only remove the old word from the command line if we have
+     * successfully found a new one to insert.
+     */
+    if (deleteword > 0) {
+	int pos = cs;
+	cs = lastpos;
+	foredel(pos - cs);
+    }
+    if (lastinsert) {
+	zfree(lastinsert, lastlen);
+	lastinsert = NULL;
+    }
+    if (l) {
+	for (node = firstnode(l); --n; incnode(node))
+	    ;
+	s = (char *)getdata(node);
+	t = s + strlen(s);
+    } else {
+	s = he->text + he->words[2*n-2];
+	t = he->text + he->words[2*n-1];
+    }
+
     save = *t;
     *t = '\0';			/* ignore trailing whitespace */
-
     lasthist = evhist;
     lastpos = cs;
-    lastinsert = ztrdup(s);
+    lastlen = t - s;
+    lastinsert = zalloc(t - s);
+    memcpy(lastinsert, s, lastlen);
     n = zmult;
     zmult = 1;
     doinsert(s);
Index: Doc/Zsh/zle.yo
===================================================================
RCS file: /cvsroot/zsh/zsh/Doc/Zsh/zle.yo,v
retrieving revision 1.16
diff -u -r1.16 zle.yo
--- Doc/Zsh/zle.yo	15 Sep 2001 20:58:33 -0000	1.16
+++ Doc/Zsh/zle.yo	5 Mar 2002 16:15:58 -0000
@@ -941,6 +941,37 @@
 replaces the word just inserted with the last word from the
 history event prior to the one just used; numeric arguments can be used in
 the same way to pick a word from that event.
+
+When called from a shell function invoked from a user-defined widget, the
+command can take one to three arguments.  The first argument specifies a
+history offset which applies to successive calls to this widget: if is -1,
+the default behaviour is used, while if it is 1, successive calls will move
+forwards through the history.  The value 0 is valid and history line
+examined by the previous execution of the command will be reexamined.  Note
+that negative numbers should be preceeded with a `tt(-)tt(-)' argument to
+avoid confusing them with options.
+
+If two arguments are given, the second specifies the word on the command
+line in normal array index notation (as a more natural alternative to the
+prefix argument).  Hence 1 is the first word, and -1 (the default) is the
+last word.
+
+If a third argument is given, its value is ignored, but it is used to
+signify that the history offset is relative to the current history line,
+rather than the one remembered after previous invocations of
+tt(insert-last-word).
+
+For example, the default behaviour of the command corresponds to
+
+example(zle insert-last-word -- -1 -1)
+
+while the command
+
+example(zle insert-last-word -- -1 1 -)
+
+always copies the first word of the line in the history immediately before
+the line being edited.  This has the side effect that later invocations of
+the widget will be relative to that line.
 )
 tindex(vi-repeat-search)
 item(tt(vi-repeat-search) (unbound) (n) (unbound))(
Index: Doc/Zsh/contrib.yo
===================================================================
RCS file: /cvsroot/zsh/zsh/Doc/Zsh/contrib.yo,v
retrieving revision 1.17
diff -u -r1.17 contrib.yo
--- Doc/Zsh/contrib.yo	7 Dec 2001 12:59:09 -0000	1.17
+++ Doc/Zsh/contrib.yo	5 Mar 2002 16:15:58 -0000
@@ -524,6 +524,20 @@
 zstyle :insert-last-assignment match '[[:alpha:]][][[:alnum:]]#=*'
 bindkey '\e=' insert-last-assignment)
 )
+findex(copy-earlier-word)
+item(tt(copy-earlier-word))(
+This widget works like a combination of tt(insert-last-word) and
+tt(copy-prev-shell-word).  Repeated invocations of the widget retrieve
+earlier words on the relevant history line.  With a numeric argument
+var(N), insert the var(N)th word from the history line; var(N) may be
+negative to count from the end of the line.
+
+If tt(insert-last-word) has been used to retrieve the last word on a
+previous history line, repeated invocations will replace that word with
+earlier words from the same line.
+
+Otherwise, the widget applies to words on the line currently being edited.
+)
 enditem()
 
 subsect(Styles)
Index: Functions/Zle/copy-earlier-word
===================================================================
RCS file: Functions/Zle/copy-earlier-word
diff -N Functions/Zle/copy-earlier-word
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ Functions/Zle/copy-earlier-word	5 Mar 2002 16:15:58 -0000
@@ -0,0 +1,19 @@
+# Copy the word before the one you last copied --- call repeatedly
+# to cycle through the list of words on the history line.
+#
+# Words in combination with insert-last-word to use the line reached,
+# and start from the word before last.  Otherwise, it will operate on
+# the current line.
+
+if (( ${NUMERIC:-0} )); then
+   # 1 means last word, 2 second last, etc.
+   (( __copyword = ${NUMERIC:-0} ))
+elif [[ -n $__copyword && $WIDGET = $LASTWIDGET ]]; then
+  (( __copyword-- ))
+elif [[ $LASTWIDGET = *insert-last-word ]]; then
+  __copyword=-2
+else
+  __copyword=-1
+fi
+
+zle .insert-last-word 0 $__copyword

-- 
Peter Stephenson <pws@xxxxxxx>                  Software Engineer
CSR Ltd., Science Park, Milton Road,
Cambridge, CB4 0WH, UK                          Tel: +44 (0)1223 392070


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