Re: PATCH: parameter substitution for exclusion by array

[Peter Stephenson <p.w.stephenson@ntlworld.com>]

On Sun, 22 Apr 2012 14:55:15 +0200
Mikael Magnusson <mikachu@gmail.com> wrote:
> Using ${path:*notexist} prints all elements of $path, not sure if that
> is what one should expect or not. ${path:|notexist} does the same but
> that makes a lot more sense to me :). ${path:*SCALAR} and :| act the
> same way, substitute all elements in $path.

You're right that using :* with something that doesn't exist or isn't an
array should produce an empty result, I hadn't picked up this
difference from :|.

Index: Src/subst.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/subst.c,v
retrieving revision 1.135
diff -p -u -r1.135 subst.c
--- Src/subst.c	22 Apr 2012 18:10:43 -0000	1.135
+++ Src/subst.c	22 Apr 2012 18:18:18 -0000
@@ -2918,6 +2918,19 @@ paramsubst(LinkList l, LinkNode n, char 
 		}
 	    }
 	    deletehashtable(ht);
+	} else if (intersect) {
+	    /*
+	     * The intersection with nothing is nothing...
+	     * Seems a bit pointless complaining that the first
+	     * expression is unset here if the second is, too.
+	     */
+	    if (!vunset) {
+		if (isarr) {
+		    aval = mkarray(NULL);
+		} else {
+		    val = dupstring("");
+		}
+	    }
 	}
     } else {			/* no ${...=...} or anything, but possible modifiers. */
 	/*
Index: Test/D04parameter.ztst
===================================================================
RCS file: /cvsroot/zsh/zsh/Test/D04parameter.ztst,v
retrieving revision 1.66
diff -p -u -r1.66 D04parameter.ztst
--- Test/D04parameter.ztst	22 Apr 2012 18:10:43 -0000	1.66
+++ Test/D04parameter.ztst	22 Apr 2012 18:18:18 -0000
@@ -182,6 +182,9 @@
   scalar='two words'
   print ${scalar:|mod}
   print ${scalar:*mod}
+  print ${args:*nonexistent}
+  empty=
+  print ${args:*empty}
 0:"|" array exclusion and "*" array intersection
 >one two
 >#foo (bar 'three'
@@ -191,6 +194,8 @@
 >two words
 >
 >two words
+>
+>
 
   str1='twocubed'
   array=(the number of protons in an oxygen nucleus)

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