PATCH: 3.1.5-pws-5++: tidying up zle parameters

[Peter Stephenson <pws@ibmth.df.unipi.it>]

This is the fix for removing zle parameters I alluded to.  You can see
the problem if you set e.g. BUFFER, then call a zle widget, then try
to use BUFFER again.  (If you already called a zle widget you'll see
the problem straight away.)  The problem was that specials didn't get
removed from the parameter table by unsetparam().  At some stage that
got altered so they did, but that was certainly wrong because then
they got freed as well.  I patched it so they didn't get removed,
either, but you could probably argue over this (what is the effect of
unsetting PATH then assigning to it, for example?)  There is now a
PM_REMOVABLE flag which says specials can be removed from the
parameter table, and I've made sure they never get freed.  Much of the
patch is slight cosmetic surgery in unsetparam_pm().

By the way, it seems to me

% typeset -T FOO foo
% foo="scalar"
% print $FOO

%

is probably a bug, so I'll try to remember to have a look at it.
Someone can remind me if I don't.  I never understood quite how
PATH/path were supposed to behave anyway, so have no comment to make
on that issue.

--- Src/Zle/compctl.c.unset	Fri Jan 29 11:28:27 1999
+++ Src/Zle/compctl.c	Fri Jan 29 17:39:42 1999
@@ -1803,7 +1803,7 @@
     struct compparam *cp;
 
     for (cp = compparams; cp->name; cp++) {
-	Param pm = createparam(cp->name, cp->type | PM_SPECIAL);
+	Param pm = createparam(cp->name, cp->type | PM_SPECIAL|PM_REMOVABLE);
 	if (!pm)
 	    pm = (Param) paramtab->getnode(paramtab, cp->name);
 	DPUTS(!pm, "param not set in makecompparams");
--- Src/Zle/zle_params.c.unset	Fri Jan 29 10:56:05 1999
+++ Src/Zle/zle_params.c	Fri Jan 29 17:38:43 1999
@@ -75,7 +75,7 @@
     struct zleparam *zp;
 
     for(zp = zleparams; zp->name; zp++) {
-	Param pm = createparam(zp->name, (zp->type | PM_SPECIAL |
+	Param pm = createparam(zp->name, (zp->type |PM_SPECIAL|PM_REMOVABLE|
 					  (ro ? PM_READONLY : 0)));
 	if (!pm)
 	    pm = (Param) paramtab->getnode(paramtab, zp->name);
--- Src/params.c.unset	Fri Jan 29 17:36:44 1999
+++ Src/params.c	Fri Jan 29 17:36:10 1999
@@ -1662,26 +1662,36 @@
 	    unsetparam_pm(altpm, 1, exp);
     }
 
-    /* If this was a local variable, we need to keep the old     *
-     * struct so that it is resurrected at the right level.      *
-     * This is partly because when an array/scalar value is set  *
-     * and the parameter used to be the other sort, unsetparam() *
-     * is called.  Beyond that, there is an ambiguity:  should   *
-     * foo() { local bar; unset bar; } make the global bar       *
-     * available or not?  The following makes the answer "no".   */
-    if ((locallevel && locallevel >= pm->level) || (pm->flags & PM_SPECIAL))
+    /*
+     * If this was a local variable, we need to keep the old
+     * struct so that it is resurrected at the right level.
+     * This is partly because when an array/scalar value is set
+     * and the parameter used to be the other sort, unsetparam()
+     * is called.  Beyond that, there is an ambiguity:  should
+     * foo() { local bar; unset bar; } make the global bar
+     * available or not?  The following makes the answer "no".
+     *
+     * Some specials, such as those used in zle, still need removing
+     * from the parameter table; they have the PM_REMOVABLE flag.
+     */
+    if ((locallevel && locallevel >= pm->level) ||
+	(pm->flags & (PM_SPECIAL|PM_REMOVABLE)) == PM_SPECIAL)
 	return;
 
-    paramtab->removenode(paramtab, pm->nam); /* remove parameter node from table */
+    /* remove parameter node from table */
+    paramtab->removenode(paramtab, pm->nam);
 
     if (pm->old) {
 	oldpm = pm->old;
 	paramtab->addnode(paramtab, oldpm->nam, oldpm);
-	if ((PM_TYPE(oldpm->flags) == PM_SCALAR) && oldpm->sets.cfn == strsetfn)
+	if ((PM_TYPE(oldpm->flags) == PM_SCALAR) &&
+	    oldpm->sets.cfn == strsetfn)
 	    adduserdir(oldpm->nam, oldpm->u.str, 0, 0);
     }
 
-    paramtab->freenode((HashNode) pm); /* free parameter node */
+    /* Even removable specials shouldn't be deleted. */
+    if (!(pm->flags & PM_SPECIAL))
+	paramtab->freenode((HashNode) pm); /* free parameter node */
 }
 
 /* Standard function to unset a parameter.  This is mostly delegated to *
--- Src/zsh.h.unset	Thu Jan 28 17:58:23 1999
+++ Src/zsh.h	Fri Jan 29 17:33:20 1999
@@ -922,6 +922,7 @@
 #define PM_DONTIMPORT	(1<<14)	/* do not import this variable                */
 #define PM_RESTRICTED	(1<<15) /* cannot be changed in restricted mode       */
 #define PM_UNSET	(1<<16)	/* has null value                             */
+#define PM_REMOVABLE	(1<<17)	/* special can be removed from paramtab */
 
 /* Flags for extracting elements of arrays and associative arrays */
 #define SCANPM_WANTVALS   (1<<0)

-- 
Peter Stephenson <pws@ibmth.df.unipi.it>       Tel: +39 050 844536
WWW:  http://www.ifh.de/~pws/
Dipartimento di Fisica, Via Buonarroti 2, 56127 Pisa, Italy