Allow splitting strings in Eshell expansions with "plain" strings

Since '$var[hello 0]' doesn't make sense when 'var' is a string, the
previous restriction was unnecessary.

* lisp/eshell/esh-var.el (Commentary): Update documentation.
(eshell-apply-indices): Allow "plain" strings to split strings.

* test/lisp/eshell/esh-var-test.el
(esh-var-test/interp-var-string-split-indices)
(esh-var-test/quoted-interp-var-string-split-indices): Update tests.

* doc/misc/eshell.texi (Dollars expansion): Update documentation.

1 files changed, 7 insertions, 10 deletions

diff --git a/lisp/eshell/esh-var.el b/lisp/eshell/esh-var.el
index 6f08a3fbc45..af89e35f553 100644
--- a/lisp/eshell/esh-var.el
+++ b/lisp/eshell/esh-var.el
@@ -74,9 +74,8 @@
 ;;   $EXPR["\\\\" 10]
 ;;
 ;; Separate on backslash characters.  Actually, the first argument --
-;; if it doesn't have the form of a number, or a plain variable name
-;; -- can be any regular expression.  So to split on numbers, use
-;; '$EXPR["[0-9]+" 10 20]'.
+;; if it doesn't have the form of a number -- can be any regular
+;; expression.  So to split on numbers, use '$EXPR["[0-9]+" 10 20]'.
 ;;
 ;;   $EXPR[hello]
 ;;
@@ -566,13 +565,11 @@ For example, to retrieve the second element of a user's record in
   (while indices
     (let ((refs (car indices)))
       (when (stringp value)
-        (let (separator)
-          (if (not (or (not (stringp (caar indices)))
-                       (string-match
-                        (concat "^" eshell-variable-name-regexp "$")
-                        (caar indices))))
-              (setq separator (caar indices)
-                    refs (cdr refs)))
+        (let (separator (index (caar indices)))
+          (when (and (stringp index)
+                     (not (get-text-property 0 'number index)))
+            (setq separator index
+                  refs (cdr refs)))
           (setq value
                 (mapcar #'eshell-convert
                         (split-string value separator)))))