Re: PATCH: nested ${(P)} (formerly SHWORDSPLIT and leading spaces)

[Peter Stephenson <p.stephenson@xxxxxxxxxxx>]

On Thu, 12 Nov 2015 09:46:28 +0000
Peter Stephenson <p.stephenson@xxxxxxxxxxx> wrote:
> > +    print ${${(P)${(P)${(P)one}}}}
> 
> Well, one thing that isn't natural is that when you're relying on the
> new logic you need that extra ${...} wrapper even in the first of the
> two cases to trigger the recursive (P).

Seems to work via the obvious fix.

diff --git a/Src/subst.c b/Src/subst.c
index c1369b5..b7f8338 100644
--- a/Src/subst.c
+++ b/Src/subst.c
@@ -1741,6 +1741,12 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int pf_flags,
      * simply removed.
      */
     int ms_flags = 0;
+    /*
+     * We need to do an extra fetch to honour the (P) flag.
+     * Complicated by the use of subexpressions that may have
+     * nested (P) flags.
+     */
+    int fetch_needed;
 
     *s++ = '\0';
     /*
@@ -2325,9 +2331,18 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int pf_flags,
 	    s = dyncat(val, s);
 	    /* Now behave po-faced as if it was always like that... */
 	    subexp = 0;
-	}
+	    /*
+	     * If this is a (P) (first test) and at the top level
+	     * (second test) we can't rely on the caller fetching
+	     * the result from the pending aspar.  So do it below.
+	     */
+	    fetch_needed = aspar && !(pf_flags & PREFORK_SUBEXP);
+	} else
+	    fetch_needed = 0; 	/* any initial aspar fetch already done */
 	v = (Value) NULL;
-    } else if (aspar) {
+    } else
+	fetch_needed = aspar;	/* aspar fetch still needed */
+    if (fetch_needed) {
 	/*
 	 * No subexpression, but in any case the value is going
 	 * to give us the name of a parameter on which we do
diff --git a/Test/D04parameter.ztst b/Test/D04parameter.ztst
index 6f325d2..210c0d8 100644
--- a/Test/D04parameter.ztst
+++ b/Test/D04parameter.ztst
@@ -1840,7 +1840,7 @@
     local two=three
     local three=four
     local -a four=(all these worlds belong to foo)
-    print ${${(P)${(P)${(P)one}}}}
+    print ${(P)${(P)${(P)one}}}
     print ${${(P)${(P)${(P)one}}}[3]}
   }
   testfn