Improve wording of Eshell variable interpolation code/documentation

* lisp/eshell/esh-arg.el (eshell-unescape-inner-double-quote): Rename
from 'eshell-parse-inner-double-quote'.

* lisp/eshell/esh-cmd.el (eshell-with-temp-command): Improve
docstring.

* lisp/eshell/esh-var.el (eshell-parse-variable-ref): Use
'eshell-unescape-inner-double-quote' and improve robustness of quoted
variable name matching.
(eshell-parse-indices): Use 'eshell-unescape-inner-double-quote'.

* doc/misc/eshell.texi (Dollars Expansion): Improve wording of
subscript notation.

3 files changed, 24 insertions, 19 deletions

diff --git a/lisp/eshell/esh-arg.el b/lisp/eshell/esh-arg.el
index e19481c4ba9..ee3f907f85c 100644
--- a/lisp/eshell/esh-arg.el
+++ b/lisp/eshell/esh-arg.el
@@ -354,8 +354,8 @@ after are both returned."
 		  (list 'eshell-escape-arg arg))))
 	  (goto-char (1+ end)))))))
 
-(defun eshell-parse-inner-double-quote (bound)
-  "Parse the inner part of a double quoted string.
+(defun eshell-unescape-inner-double-quote (bound)
+  "Unescape escaped characters inside a double-quoted string.
 The string to parse starts at point and ends at BOUND.
 
 If Eshell is currently parsing a quoted string and there are any
diff --git a/lisp/eshell/esh-cmd.el b/lisp/eshell/esh-cmd.el
index 04b54d9d791..8be1136e311 100644
--- a/lisp/eshell/esh-cmd.el
+++ b/lisp/eshell/esh-cmd.el
@@ -350,24 +350,27 @@ This only returns external (non-Lisp) processes."
 
 (defvar eshell--sep-terms)
 
-(defmacro eshell-with-temp-command (command &rest body)
-  "Narrow the buffer to COMMAND and execute the forms in BODY.
-COMMAND can either be a string, or a cons cell demarcating a
-buffer region.  If COMMAND is a string, temporarily insert it
-into the buffer before narrowing.  Point will be set to the
-beginning of the narrowed region.
+(defmacro eshell-with-temp-command (region &rest body)
+  "Narrow the buffer to REGION and execute the forms in BODY.
+
+REGION is a cons cell (START . END) that specifies the region to
+which to narrow the buffer.  REGION can also be a string, in
+which case the macro temporarily inserts it into the buffer at
+point, and narrows the buffer to the inserted string.  Before
+executing BODY, point is set to the beginning of the narrowed
+REGION.
 
 The value returned is the last form in BODY."
   (declare (indent 1))
-  `(let ((cmd ,command))
-     (if (stringp cmd)
+  `(let ((reg ,region))
+     (if (stringp reg)
          ;; Since parsing relies partly on buffer-local state
          ;; (e.g. that of `eshell-parse-argument-hook'), we need to
          ;; perform the parsing in the Eshell buffer.
          (let ((begin (point)) end
 	       (inhibit-point-motion-hooks t))
            (with-silent-modifications
-             (insert cmd)
+             (insert reg)
              (setq end (point))
              (unwind-protect
                  (save-restriction
@@ -376,8 +379,8 @@ The value returned is the last form in BODY."
                    ,@body)
                (delete-region begin end))))
        (save-restriction
-         (narrow-to-region (car cmd) (cdr cmd))
-         (goto-char (car cmd))
+         (narrow-to-region (car reg) (cdr reg))
+         (goto-char (car reg))
          ,@body))))
 
 (defun eshell-parse-command (command &optional args toplevel)
diff --git a/lisp/eshell/esh-var.el b/lisp/eshell/esh-var.el
index af89e35f553..8746f2bb931 100644
--- a/lisp/eshell/esh-var.el
+++ b/lisp/eshell/esh-var.el
@@ -437,7 +437,7 @@ Possible options are:
             `(eshell-convert
               (eshell-command-to-value
                (eshell-as-subcommand
-                ,(let ((subcmd (or (eshell-parse-inner-double-quote end)
+                ,(let ((subcmd (or (eshell-unescape-inner-double-quote end)
                                    (cons (point) end)))
                        (eshell-current-quoted nil))
                    (eshell-parse-command subcmd)))))
@@ -470,13 +470,15 @@ Possible options are:
     (condition-case nil
         `(eshell-command-to-value
           (eshell-lisp-command
-           ',(read (or (eshell-parse-inner-double-quote (point-max))
+           ',(read (or (eshell-unescape-inner-double-quote (point-max))
                        (current-buffer)))))
       (end-of-file
        (throw 'eshell-incomplete ?\())))
-   ((looking-at (rx (or "'" "\"" "\\\"")))
-    (eshell-with-temp-command (or (eshell-parse-inner-double-quote (point-max))
-                                  (cons (point) (point-max)))
+   ((looking-at (rx-to-string
+                 `(or "'" ,(if eshell-current-quoted "\\\"" "\""))))
+    (eshell-with-temp-command
+        (or (eshell-unescape-inner-double-quote (point-max))
+            (cons (point) (point-max)))
       (let ((name (if (eq (char-after) ?\')
                       (eshell-parse-literal-quote)
                     (eshell-parse-double-quote))))
@@ -506,7 +508,7 @@ For example, \"[0 1][2]\" becomes:
 	(if (not end)
 	    (throw 'eshell-incomplete ?\[)
 	  (forward-char)
-          (eshell-with-temp-command (or (eshell-parse-inner-double-quote end)
+          (eshell-with-temp-command (or (eshell-unescape-inner-double-quote end)
                                         (cons (point) end))
 	    (let (eshell-glob-function (eshell-current-quoted nil))
 	      (setq indices (cons (eshell-parse-arguments