Allow using dollar expansions in Eshell conditionals

* lisp/eshell/esh-cmd.el (eshell-structure-basic-command): Forms
beginning with 'eshell-escape-arg' are "data-wise".

* test/lisp/eshell/esh-cmd-tests.el (esh-cmd-test/while-loop)
(esh-cmd-test/until-loop, esh-cmd-test/if-statement)
(esh-cmd-test/if-else-statement, esh-cmd-test/unless-statement)
(esh-cmd-test/unless-else-statement): Use variable interpolation.
(esh-cmd-test/while-loop-ext-cmd, esh-cmd-test/until-loop-ext-cmd)
(esh-cmd-test/if-else-statement-ext-cmd)
(esh-cmd-test/unless-else-statement-ext-cmd): New tests, adapted from
the existing ones.

* doc/misc/eshell.texi (Control Flow): Update documentation for
conditionals (bug#57129).

1 files changed, 50 insertions, 10 deletions

diff --git a/test/lisp/eshell/esh-cmd-tests.el b/test/lisp/eshell/esh-cmd-tests.el
index 1d5cd29d7cf..b31159a1a8f 100644
--- a/test/lisp/eshell/esh-cmd-tests.el
+++ b/test/lisp/eshell/esh-cmd-tests.el
@@ -132,6 +132,15 @@ e.g. \"{(+ 1 2)} 3\" => 3"
 
 (ert-deftest esh-cmd-test/while-loop ()
   "Test invocation of a while loop."
+  (with-temp-eshell
+   (let ((eshell-test-value '(0 1 2)))
+     (eshell-command-result-p
+      (concat "while $eshell-test-value "
+              "{ setq eshell-test-value (cdr eshell-test-value) }")
+      "(1 2)\n(2)\n"))))
+
+(ert-deftest esh-cmd-test/while-loop-ext-cmd ()
+  "Test invocation of a while loop using an external command."
   (skip-unless (executable-find "["))
   (with-temp-eshell
    (let ((eshell-test-value 0))
@@ -142,6 +151,15 @@ e.g. \"{(+ 1 2)} 3\" => 3"
 
 (ert-deftest esh-cmd-test/until-loop ()
   "Test invocation of an until loop."
+  (with-temp-eshell
+   (let ((eshell-test-value nil))
+     (eshell-command-result-p
+      (concat "until $eshell-test-value "
+              "{ setq eshell-test-value t }")
+      "t\n"))))
+
+(ert-deftest esh-cmd-test/until-loop-ext-cmd ()
+  "Test invocation of an until loop using an external command."
   (skip-unless (executable-find "["))
   (with-temp-eshell
    (let ((eshell-test-value 0))
@@ -152,15 +170,26 @@ e.g. \"{(+ 1 2)} 3\" => 3"
 
 (ert-deftest esh-cmd-test/if-statement ()
   "Test invocation of an if statement."
-  (skip-unless (executable-find "["))
   (with-temp-eshell
-   (eshell-command-result-p "if {[ foo = foo ]} {echo yes}"
-                            "yes\n")
-   (eshell-command-result-p "if {[ foo = bar ]} {echo yes}"
-                            "\\`\\'")))
+   (let ((eshell-test-value t))
+     (eshell-command-result-p "if $eshell-test-value {echo yes}"
+                              "yes\n"))
+   (let ((eshell-test-value nil))
+     (eshell-command-result-p "if $eshell-test-value {echo yes}"
+                              "\\`\\'"))))
 
 (ert-deftest esh-cmd-test/if-else-statement ()
   "Test invocation of an if/else statement."
+  (with-temp-eshell
+   (let ((eshell-test-value t))
+     (eshell-command-result-p "if $eshell-test-value {echo yes} {echo no}"
+                              "yes\n"))
+   (let ((eshell-test-value nil))
+     (eshell-command-result-p "if $eshell-test-value {echo yes} {echo no}"
+                              "no\n"))))
+
+(ert-deftest esh-cmd-test/if-else-statement-ext-cmd ()
+  "Test invocation of an if/else statement using an external command."
   (skip-unless (executable-find "["))
   (with-temp-eshell
    (eshell-command-result-p "if {[ foo = foo ]} {echo yes} {echo no}"
@@ -170,15 +199,26 @@ e.g. \"{(+ 1 2)} 3\" => 3"
 
 (ert-deftest esh-cmd-test/unless-statement ()
   "Test invocation of an unless statement."
-  (skip-unless (executable-find "["))
   (with-temp-eshell
-   (eshell-command-result-p "unless {[ foo = foo ]} {echo no}"
-                            "\\`\\'")
-   (eshell-command-result-p "unless {[ foo = bar ]} {echo no}"
-                            "no\n")))
+   (let ((eshell-test-value t))
+     (eshell-command-result-p "unless $eshell-test-value {echo no}"
+                              "\\`\\'"))
+   (let ((eshell-test-value nil))
+     (eshell-command-result-p "unless $eshell-test-value {echo no}"
+                              "no\n"))))
 
 (ert-deftest esh-cmd-test/unless-else-statement ()
   "Test invocation of an unless/else statement."
+  (with-temp-eshell
+   (let ((eshell-test-value t))
+     (eshell-command-result-p "unless $eshell-test-value {echo no} {echo yes}"
+                              "yes\n"))
+   (let ((eshell-test-value nil))
+     (eshell-command-result-p "unless $eshell-test-value {echo no} {echo yes}"
+                              "no\n"))))
+
+(ert-deftest esh-cmd-test/unless-else-statement-ext-cmd ()
+  "Test invocation of an unless/else statement using an external command."
   (skip-unless (executable-find "["))
   (with-temp-eshell
    (eshell-command-result-p "unless {[ foo = foo ]} {echo no} {echo yes}"