Re: Completion problems.

[Sven Wischnowsky <wischnow@informatik.hu-berlin.de>]

Bart Schaefer wrote:

> I think (2) would be quite useful in other contexts anyway.  Perhaps (Q)?
> (And we could add (q) which means the same as :q, just for completeness.)

;-) I've been thinking about (q), too.

> There is some question about what paramter unquoting should do in the case
> of mismatched quotes.  I can think of cases where you'd want it to produce
> the same errors as using that same quoting in a command, and other cases
> (like completion) where you'd just like it to assume the closing quote.

Right. Maybe I'll find some time soon...

> } [...] with match specs using `*'-patterns new stuff can be inserted
> } anywhere in the word. To retain the single quotes the completion code
> } would have to keep track of the original positions and would have to
> } calculate the new positions for every single or double quote inside
> } the word. This is extremly difficult, expensive (i.e. slow), and at
> } least I wouldn't implement it (if anyone else is interested: try to
> } find out how the completion code now handles completion inside braces
> } -- you would have to do something similar, but not only for two
> } places, but for a whole list of positions).
> 
> I almost hate to mention this, but braces can be nested, and right now
> completion doesn't work in that case -- presumably *because* it isn't
> keeping track of a list of positions.

I didn't write the original in-brace-completion-code, but I think it
was done in the way it was done mainly because `a{b<TAB>' is
relatively easy to parse and there is only one possible prefix to
complete whereas with `a{b{c' we would have to collect multiple parts
of the string to complete (instead of just removing a bit) and with
`a{b,c}d{e<TAB>' we would have to handle both `abde' and `acde', of
course. At the time completion in braces was added the code only
inserted a prefix and/or a suffix at the cursor position so there
wasn't a problem with keeping a list of positions.

Do you want to say that completion in nested braces should be
possible? (Horrors. But, yes, maybe it should be...)

> There are similar (?) problems with nested parameter substitutions:
> 
> zagzig<1> echo ${${p<TAB>
> path     perl     prompt   psvar           
> zagzig<1> echo ${${pa<TAB>
> zagzig<1> echo ${${path} 
>                          ^Cursor is now here; arguably no space should
>                           have been added, because it can't possibly be
>                           correct in that context.  Also, if you now type
>                           a right-curly, the trailing space is deleted,
>                           but the right-curly is not inserted (which I
>                           guess is theoretically correct).

Completion inside parameter expansions is a different thing because
there we only look at the name and ignore the surrounding parts of the 
string.
The patch below makes the code check for nested parameter expansions
and not insert a space then. The algorithm for testing for nested
expansions is very simple, but I think it should get most things
right.
The patch also makes `}' remove the suffix for completion after
`${...' in the new completion stuff and avoid the space on nested
expansions there, too.
Btw. did you all know that the new completion code currently doesn't
respect AUTO_PARAM_SLASH? I knew, but didn't tell anyone. Naughty me.

> BTW, expand-or-complete is a pain in the butt when combined with braces,
> because as soon as you close the braces the next TAB *expands* them,
> leaving you with multiple half-finished words.  You can prevent this by
> setting GLOB_COMPLETE, but in that case completion after the right-brace
> still doesn't work.

See above -- completion after a closed `{a,b}' would be something
completely new: multiple prefixes. We would have to generate multiple
sets of matches and then select those present in all sets.

Bye
 Sven

diff -u os/Zle/comp.h Src/Zle/comp.h
--- os/Zle/comp.h	Mon Aug  2 11:44:52 1999
+++ Src/Zle/comp.h	Thu Aug  5 10:47:52 1999
@@ -227,7 +227,8 @@
 #define CMF_FILE     1		/* this is a file */
 #define CMF_REMOVE   2		/* remove the suffix */
 #define CMF_PARBR    4		/* paramter expansion with a brace */
-#define CMF_NOLIST   8		/* should not be listed */
+#define CMF_PARNEST  8		/* nested paramter expansion */
+#define CMF_NOLIST  16		/* should not be listed */
 
 
 /* Stuff for completion matcher control. */
diff -u os/Zle/zle_tricky.c Src/Zle/zle_tricky.c
--- os/Zle/zle_tricky.c	Wed Aug  4 11:38:31 1999
+++ Src/Zle/zle_tricky.c	Thu Aug  5 10:55:33 1999
@@ -728,7 +728,7 @@
     if ((*p == String || *p == Qstring) && p[1] != Inpar && p[1] != Inbrack) {
 	/* This is really a parameter expression (not $(...) or $[...]). */
 	char *b = p + 1, *e = b;
-	int n = 0, br = 1;
+	int n = 0, br = 1, nest = 0;
 
 	if (*b == Inbrace) {
 	    char *tb = b;
@@ -740,6 +740,10 @@
 	    /* Ignore the possible (...) flags. */
 	    b++, br++;
 	    n = skipparens(Inpar, Outpar, &b);
+
+	    for (tb = p - 1; tb > s && *tb != Outbrace && *tb != Inbrace; tb--);
+	    if (tb > s && *tb == Inbrace && (tb[-1] == String || *tb == Qstring))
+		nest = 1;
 	}
 
 	/* Ignore the stuff before the parameter name. */
@@ -788,9 +792,11 @@
 	     * global variables. */
 
 	    if (set) {
-		if (br >= 2)
+		if (br >= 2) {
 		    mflags |= CMF_PARBR;
-
+		    if (nest)
+			mflags |= CMF_PARNEST;
+		}
 		/* Get the prefix (anything up to the character before the name). */
 		isuf = dupstring(e);
 		untokenize(isuf);
@@ -7728,6 +7734,8 @@
 	    minfo.insc++;
 	    if (minfo.we)
 		minfo.end += minfo.insc;
+	    if (m->flags & CMF_PARNEST)
+		havesuff = 1;
 	}
 	if ((m->flags & CMF_FILE) || (m->ripre && isset(AUTOPARAMSLASH))) {
 	    /* If we have a filename or we completed a parameter name      *
@@ -7741,11 +7749,12 @@
 		t = 1;
 	    else {
 		/* Build the path name. */
-		if (m->ripre && !*psuf) {
+		if (m->ripre && !*psuf && !(m->flags & CMF_PARNEST)) {
 		    int ne = noerrs;
 
-		    p = (char *) zhalloc(strlen(m->ripre) + strlen(str) + 1);
-		    sprintf(p, "%s%s", m->ripre, str);
+		    p = (char *) zhalloc(strlen(m->ripre) + strlen(str) + 2);
+		    sprintf(p, "%s%s%c", m->ripre, str,
+			    ((m->flags & CMF_PARBR) ? Outbrace : '\0'));
 		    noerrs = 1;
 		    parsestr(p);
 		    singsub(&p);
diff -u oc/Base/_brace_parameter Completion/Base/_brace_parameter
--- oc/Base/_brace_parameter	Mon Aug  2 11:45:10 1999
+++ Completion/Base/_brace_parameter	Thu Aug  5 11:00:29 1999
@@ -7,6 +7,8 @@
 if [[ "$SUFFIX" = *\}* ]]; then
   ISUFFIX="${SUFFIX#*\}}$ISUFFIX"
   SUFFIX="${SUFFIX%%\}*}"
+elif [[ "$LBUFFER" = *\$\{[^}]#\$\{[^}]#$PREFIX ]]; then
+  suf='}'
 else
   suf='} '
 fi
@@ -18,4 +20,4 @@
 
 [[ n -gt 0 ]] && suf=''
 
-_parameters -Qs "${q[1,-n-1]}" -S "$suf" -r '-:?#%+=[/'
+_parameters -Qs "${q[1,-n-1]}" -S "$suf" -r '-:?#%+=[/}'

--
Sven Wischnowsky                         wischnow@informatik.hu-berlin.de