Re: bug

[Peter Stephenson <p.w.stephenson@xxxxxxxxxxxx>]

On Tue, 20 Dec 2011 19:05:11 -0800
Bart Schaefer <schaefer@xxxxxxxxxxxxxxxx> wrote:
> On Dec 20,  6:08pm, Ray Andrews wrote:
> }
> } function z
> } {
> } var=$1
> } echo "var:/${1:0:1}/${1:1:1}/${1:2:1}/"
> } }
> } 
> } $ z abcde
> } var: /a/a/b/
> 
>      For further compatibility with other shells there is a special case
>      for array offset 0.  This usually accesses to the first element of
>      the array.  However, if the substitution refers the positional
>      parameter array, e.g. $@ or $*, then offset 0 instead refers to
>      $0, offset 1 refers to $1, and so on.  In other words, the
>      positional parameter array is effectively extended by prepending
>      $0.  Hence ${*:0:1} substitutes $0 and ${*:1:1} substitutes $1.
> 
> So :0:1 is acting on the invisible $0 even though the reference is to
> an individual positional parameter rather than to the positional array.

Yes, it should only be doing that for array values.

Index: Src/subst.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/subst.c,v
retrieving revision 1.129
diff -p -u -r1.129 subst.c
--- Src/subst.c	28 Nov 2011 09:48:22 -0000	1.129
+++ Src/subst.c	21 Dec 2011 22:31:35 -0000
@@ -2878,24 +2878,26 @@ paramsubst(LinkList l, LinkNode n, char 
 			    return NULL;
 		    }
 		}
-		if (horrible_offset_hack) {
-		    /*
-		     * As part of the 'orrible hoffset 'ack,
-		     * (what hare you? Han 'orrible hoffset 'ack,
-		     * sergeant major), if we are given a ksh/bash/POSIX
-		     * style positional parameter array which includes
-		     * offset 0, we use $0.
-		     */
-		    if (offset == 0 && isarr) {
-			offset_hack_argzero = 1;
-		    } else if (offset > 0) {
-			offset--;
-		    }
-		}
 		if (isarr) {
-		    int alen = arrlen(aval), count;
+		    int alen, count;
 		    char **srcptr, **dstptr, **newarr;
 
+		    if (horrible_offset_hack) {
+			/*
+			 * As part of the 'orrible hoffset 'ack,
+			 * (what hare you? Han 'orrible hoffset 'ack,
+			 * sergeant major), if we are given a ksh/bash/POSIX
+			 * style positional parameter array which includes
+			 * offset 0, we use $0.
+			 */
+			if (offset == 0) {
+			    offset_hack_argzero = 1;
+			} else if (offset > 0) {
+			    offset--;
+			}
+		    }
+
+		    alen = arrlen(aval);
 		    if (offset < 0) {
 			offset += alen;
 			if (offset < 0)


-- 
Peter Stephenson <p.w.stephenson@xxxxxxxxxxxx>
Web page now at http://homepage.ntlworld.com/p.w.stephenson/