51402: Some ksh/bash features, additional sanity checking

* Add "unset -n"
* Allow and enforce "typeset -n -r" for read-only references
* "can't change type via subscript reference" error
* Better checking for self-referential declarations/assignments
* Ksh-style "foo=bar; typeset -n foo" creates foo=bar reference
* Support "typeset -n ref; for ref in ..."
* Subscripted references use NO_EXEC for safety
* References assigned in called scopes reset scope at end
* Allow named references to $! $? $$ $- $0 $_

1 files changed, 4 insertions, 0 deletions

diff --git a/Src/zsh.h b/Src/zsh.h
index 1e35bd33e..96b4b06bd 100644
--- a/Src/zsh.h
+++ b/Src/zsh.h
@@ -1935,6 +1935,9 @@ struct tieddata {
 #define PM_NAMEDDIR     (1<<29) /* has a corresponding nameddirtab entry    */
 #define PM_NAMEREF      (1<<30) /* pointer to a different parameter         */
 
+#define PM_SELFREF	PM_UNIQUE	/* Overload when namerefs resolved  */
+#define PM_NEWREF	PM_SINGLE	/* Overload in for-loop namerefs    */
+
 /* The option string corresponds to the first of the variables above */
 #define TYPESET_OPTSTR "aiEFALRZlurtxUhHT"
 
@@ -1959,6 +1962,7 @@ struct tieddata {
 				  * elements
 				  */
 #define SCANPM_CHECKING   (1<<10) /* Check if set, no need to create */
+#define SCANPM_NOEXEC     (1<<11) /* No command substitutions, etc. */
 /* "$foo[@]"-style substitution
  * Only sign bit is significant
  */