Ensure Eshell variable aliases properly handle indexing

* lisp/eshell/em-dirs.el (eshell-dirs-initialize): Properly handle
indexing for variable aliases.

* lisp/eshell/esh-var (eshell-variable-aliases-list): Properly handle
indexing for variable aliases, and add SIMPLE-FUNCTION entry for
aliases.
(eshell-get-variable): Update how variable alias functions are called.

* test/lisp/eshell/em-alias-tests.el
(em-alias-test/alias-arg-vars-indices)
(em-alias-test/alias-arg-vars-split-indices)
(em-alias-test/alias-all-args-var-split-indices):
* test/lisp/eshell/em-dirs-tests.el (em-dirs-test/pwd-var-indices)
(em-dirs-test/oldpwd-var-indices)
(em-dirs-test/directory-ring-var-indices):
* test/lisp/eshell/esh-var-tests.el
(esh-var-test/inside-emacs-var-split-indices)
(esh-var-test/last-result-var-split-indices): New tests.
(esh-var-test/last-arg-var-split-indices): Expand test to check
conversion behavior inside double quotes (bug#56509).

3 files changed, 71 insertions, 2 deletions

diff --git a/test/lisp/eshell/em-alias-tests.el b/test/lisp/eshell/em-alias-tests.el
index 762f125a786..497159e3460 100644
--- a/test/lisp/eshell/em-alias-tests.el
+++ b/test/lisp/eshell/em-alias-tests.el
@@ -47,6 +47,23 @@
    (eshell-insert-command "alias show-args 'printnl $0 \"$1 $2\"'")
    (eshell-command-result-p "show-args one two" "show-args\none two\n")))
 
+(ert-deftest em-alias-test/alias-arg-vars-indices ()
+  "Test alias with $1, $2, ... variables using indices"
+  (with-temp-eshell
+   (eshell-insert-command "alias funny-sum '+ $1[0] $2[1]'")
+   (eshell-command-result-p "funny-sum (list 1 2) (list 3 4)"
+                            "5\n")))
+
+(ert-deftest em-alias-test/alias-arg-vars-split-indices ()
+  "Test alias with $0, $1, ... variables using split indices"
+  (with-temp-eshell
+   (eshell-insert-command "alias my-prefix 'echo $0[- 0]'")
+   (eshell-command-result-p "my-prefix"
+                            "my\n")
+   (eshell-insert-command "alias funny-sum '+ $1[: 0] $2[: 1]'")
+   (eshell-command-result-p "funny-sum 1:2 3:4"
+                            "5\n")))
+
 (ert-deftest em-alias-test/alias-all-args-var ()
   "Test alias with the $* variable"
   (with-temp-eshell
@@ -61,4 +78,10 @@
    (eshell-insert-command "alias add-pair '+ $*[0] $*[1]'")
    (eshell-command-result-p "add-pair 1 2" "3\n")))
 
+(ert-deftest em-alias-test/alias-all-args-var-split-indices ()
+  "Test alias with the $* variable using split indices"
+  (with-temp-eshell
+   (eshell-insert-command "alias add-funny-pair '+ $*[0][: 0] $*[1][: 1]'")
+   (eshell-command-result-p "add-funny-pair 1:2 3:4" "5\n")))
+
 ;; em-alias-tests.el ends here
diff --git a/test/lisp/eshell/em-dirs-tests.el b/test/lisp/eshell/em-dirs-tests.el
index 69480051e49..8e96cc07471 100644
--- a/test/lisp/eshell/em-dirs-tests.el
+++ b/test/lisp/eshell/em-dirs-tests.el
@@ -40,6 +40,14 @@
     (should (equal (eshell-test-command-result "echo $PWD")
                    (expand-file-name default-directory)))))
 
+(ert-deftest em-dirs-test/pwd-var-indices ()
+  "Test using the $PWD variable with indices."
+  (let ((default-directory "/some/path/here"))
+    (should (equal (eshell-test-command-result "echo $PWD[/ 1]")
+                   "some"))
+    (should (equal (eshell-test-command-result "echo $PWD[/ 1 3]")
+                   '("some" "here")))))
+
 (ert-deftest em-dirs-test/short-pwd-var ()
   "Test using the $+ (current directory) variable."
   (let ((default-directory "/some/path"))
@@ -56,6 +64,16 @@
      (eshell-command-result-p "echo $OLDPWD"
                               "/some/path\n"))))
 
+(ert-deftest em-dirs-test/oldpwd-var-indices ()
+  "Test using the $OLDPWD variable with indices."
+  (let (eshell-last-dir-ring-file-name)
+    (with-temp-eshell
+     (ring-insert eshell-last-dir-ring "/some/path/here")
+     (eshell-command-result-p "echo $OLDPWD[/ 1]"
+                              "some\n")
+     (eshell-command-result-p "echo $OLDPWD[/ 1 3]"
+                              "(\"some\" \"here\")\n"))))
+
 (ert-deftest em-dirs-test/directory-ring-var ()
   "Test using the $- (directory ring) variable."
   (let (eshell-last-dir-ring-file-name)
@@ -71,4 +89,14 @@
      (eshell-command-result-p "echo $-[1]"
                               "/some/path\n"))))
 
+(ert-deftest em-dirs-test/directory-ring-var-indices ()
+  "Test using the $- (directory ring) variable with multiple indices."
+  (let (eshell-last-dir-ring-file-name)
+    (with-temp-eshell
+     (ring-insert eshell-last-dir-ring "/some/path/here")
+     (eshell-command-result-p "echo $-[0][/ 1]"
+                              "some\n")
+     (eshell-command-result-p "echo $-[1][/ 1 3]"
+                              "(\"some\" \"here\")\n"))))
+
 ;; em-dirs-tests.el ends here
diff --git a/test/lisp/eshell/esh-var-tests.el b/test/lisp/eshell/esh-var-tests.el
index 955190aee0b..54e701a6aab 100644
--- a/test/lisp/eshell/esh-var-tests.el
+++ b/test/lisp/eshell/esh-var-tests.el
@@ -494,6 +494,12 @@ inside double-quotes"
                             (format "INSIDE_EMACS=%s,eshell"
                                     emacs-version))))
 
+(ert-deftest esh-var-test/inside-emacs-var-split-indices ()
+  "Test using \"INSIDE_EMACS\" with split indices"
+  (with-temp-eshell
+   (eshell-command-result-p "echo $INSIDE_EMACS[, 1]"
+                            "eshell")))
+
 (ert-deftest esh-var-test/last-result-var ()
   "Test using the \"last result\" ($$) variable"
   (with-temp-eshell
@@ -506,6 +512,16 @@ inside double-quotes"
    (eshell-command-result-p "+ 1 2; + $$ $$"
                             "3\n6\n")))
 
+(ert-deftest esh-var-test/last-result-var-split-indices ()
+  "Test using the \"last result\" ($$) variable with split indices"
+  (with-temp-eshell
+   (eshell-command-result-p
+    "string-join (list \"01\" \"02\") :; + $$[: 1] 3"
+    "01:02\n5\n")
+   (eshell-command-result-p
+    "string-join (list \"01\" \"02\") :; echo \"$$[: 1]\""
+    "01:02\n02\n")))
+
 (ert-deftest esh-var-test/last-arg-var ()
   "Test using the \"last arg\" ($_) variable"
   (with-temp-eshell
@@ -523,7 +539,9 @@ inside double-quotes"
 (ert-deftest esh-var-test/last-arg-var-split-indices ()
   "Test using the \"last arg\" ($_) variable with split indices"
   (with-temp-eshell
-   (eshell-command-result-p "concat 01:02 03:04; echo $_[0][: 1]"
-                            "01:0203:04\n2\n")))
+   (eshell-command-result-p "concat 01:02 03:04; + $_[0][: 1] 5"
+                            "01:0203:04\n7\n")
+   (eshell-command-result-p "concat 01:02 03:04; echo \"$_[0][: 1]\""
+                            "01:0203:04\n02\n")))
 
 ;; esh-var-tests.el ends here