[PATCH 2/3] jp: Use `(nil)` for empty identifier strings

[Joey Pabalinas <joeypabalinas@xxxxxxxxx>]

Indicate the presence of an empty identifier string using `(nil)`; the
empty string case should still provide a somewhat useful error message using:

> zsh:1: not an identifier: (nil)

rather than:

> zsh:1: not an identifier:

which is fairly confusing and sort of useless.

Signed-off-by: Joey Pabalinas <joeypabalinas@xxxxxxxxx>
Requested-by: Bart Schaefer <schaefer@xxxxxxxxxxxxxxxx>

 2 files changed, 6 insertions(+)

diff --git a/Src/params.c b/Src/params.c
index de7730ae735a44963c..44a942296f23ddf88f 100644
--- a/Src/params.c
+++ b/Src/params.c
@@ -3004,6 +3004,8 @@ assignsparam(char *s, char *val, int flags)
     int sstart, created = 0;
 
     if (!isident(s)) {
+	if (!strcmp(s, ""))
+	    s = "(nil)";
 	zerr("not an identifier: %s", s);
 	zsfree(val);
 	errflag |= ERRFLAG_ERROR;
diff --git a/Src/subst.c b/Src/subst.c
index d027e3d83cadc631a7..5fe69a6b94bfad8d9e 100644
--- a/Src/subst.c
+++ b/Src/subst.c
@@ -3150,6 +3150,8 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int pf_flags,
 	}
 	if (*itype_end(s, IIDENT, 0)) {
 	    untokenize(s);
+	    if (!strcmp(s, ""))
+		s = "(nil)";
 	    zerr("not an identifier: %s", s);
 	    return NULL;
 	}
@@ -3210,6 +3212,8 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int pf_flags,
 	++s;
 	if (*itype_end(s, IIDENT, 0)) {
 	    untokenize(s);
+	    if (!strcmp(s, ""))
+		s = "(nil)";
 	    zerr("not an identifier: %s", s);
 	    return NULL;
 	}
-- 
2.15.1