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Improve evaluation of conditional Eshell forms

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This simplifies the logic for building these forms and also fixes an
issue where a subcommand in a "&&" or "||" conditional had its output
suppressed.

* lisp/eshell/esh-cmd.el (eshell-structure-basic-command): Make
obsolete.
(eshell-silence-test-command): New function...
(eshell-rewrite-while-command, eshell-rewrite-if-command): ... use it,
and make the command form ourselves.
(eshell-parse-pipeline): Use 'and' and 'or' to make the conditional
command sequence.
(eshell-command-success): New macro.
(eshell-do-eval): Add support for 'and' and 'or' forms.

* test/lisp/eshell/esh-cmd-tests.el (esh-cmd-test/and-operator/output)
(esh-cmd-test/or-operator/output): New tests.
This commit is contained in:
Jim Porter 2024-11-01 10:40:25 -07:00
parent ffda8dfe84
commit 673c906a5b
2 changed files with 84 additions and 24 deletions
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78
lisp/eshell/esh-cmd.el
View file

@ -556,6 +556,7 @@ implemented via rewriting, rather than as a function."
The first of NAMES should be the positive form, and the second the
negative. It's not likely that users should ever need to call this
function."
(declare (obsolete nil "31.1"))
(unless test
(error "Missing test for `%s' command" keyword))
@ -586,6 +587,12 @@ function."
;; Finally, create the form that represents this structured command.
`(,func ,test ,@body))
(defun eshell-silence-test-command (terms)
"If TERMS is a subcommand, wrap it in `eshell-commands' to silence output."
(if (memq (car-safe terms) '(eshell-as-subcommand eshell-lisp-command))
`(eshell-command-success (eshell-commands ,terms t))
terms))
(defun eshell-rewrite-while-command (terms)
"Rewrite a `while' command into its equivalent Eshell command form.
Because the implementation of `while' relies upon conditional
@ -593,10 +600,13 @@ evaluation of its argument (i.e., use of a Lisp special form), it
must be implemented via rewriting, rather than as a function."
(when (and (stringp (car terms))
(member (car terms) '("while" "until")))
(eshell-structure-basic-command
'while '("while" "until") (car terms)
(cadr terms)
(caddr terms))))
(unless (cadr terms)
(error "Missing test for `while' command"))
(let ((condition (eshell-silence-test-command (cadr terms))))
(unless (string= (car terms) "while")
(setq condition `(not ,condition)))
`(while ,condition
,(caddr terms)))))
(defun eshell-rewrite-if-command (terms)
"Rewrite an `if' command into its equivalent Eshell command form.
@ -605,18 +615,21 @@ evaluation of its argument (i.e., use of a Lisp special form), it
must be implemented via rewriting, rather than as a function."
(when (and (stringp (car terms))
(member (car terms) '("if" "unless")))
(eshell-structure-basic-command
'if '("if" "unless") (car terms)
(cadr terms)
(caddr terms)
(if (equal (nth 3 terms) "else")
;; If there's an "else" keyword, allow chaining together
;; multiple "if" forms...
(or (eshell-rewrite-if-command (nthcdr 4 terms))
(nth 4 terms))
;; ... otherwise, only allow a single "else" block (without the
;; keyword) as before for compatibility.
(nth 3 terms)))))
(unless (cadr terms)
(error "Missing test for `while' command"))
(let ((condition (eshell-silence-test-command (cadr terms)))
(then (caddr terms))
(else (if (equal (nth 3 terms) "else")
;; If there's an "else" keyword, allow chaining
;; together multiple "if" forms...
(or (eshell-rewrite-if-command (nthcdr 4 terms))
(nth 4 terms))
;; ... otherwise, only allow a single "else" block
;; (without the keyword) as before for compatibility.
(nth 3 terms))))
(unless (string= (car terms) "if")
(setq condition `(not ,condition)))
`(if ,condition ,then ,else))))
(defun eshell-set-exit-info (status &optional result)
"Set the exit status and result for the last command.
@ -665,9 +678,10 @@ This means an exit code of 0."
sep-terms (nreverse sep-terms))
(while results
(cl-assert (car sep-terms))
(setq final (eshell-structure-basic-command
'if (string= (pop sep-terms) "&&") "if"
(pop results) final)))
(setq final `(,(if (string= (pop sep-terms) "&&") 'and 'or)
(eshell-command-success
(eshell-deferrable ,(pop results)))
,final)))
final))
(defun eshell-parse-subcommand-argument ()
@ -751,12 +765,12 @@ if none)."
;; `eshell-do-eval' [Iterative evaluation]:
;;
;; @ Don't use special forms that conditionally evaluate their
;; arguments, such as `let*', unless Eshell explicitly supports
;; them. Eshell supports the following special forms: `catch',
;; `condition-case', `if', `let', `prog1', `progn', `quote', `setq',
;; `unwind-protect', and `while'.
;; arguments, such as `let*', unless Eshell explicitly supports them.
;; Eshell supports the following special forms: `and', `catch',
;; `condition-case', `if', `let', `or', `prog1', `progn', `quote',
;; `setq', `unwind-protect', and `while'.
;;
;; @ The two `special' variables are `eshell-current-handles' and
;; @ The two "special" variables are `eshell-current-handles' and
;; `eshell-current-subjob-p'. Bind them locally with a `let' if you
;; need to change them. Change them directly only if your intention
;; is to change the calling environment.
@ -803,6 +817,10 @@ returning it as (:eshell-background . PROCESSES)."
(eshell-with-handles (,(not silent) 'append)
,object)))
(defmacro eshell-command-success (command)
"Return non-nil if COMMAND exits successfully."
`(progn ,command (eshell-exit-success-p)))
(defvar eshell-this-command-hook nil)
(defmacro eshell-do-command (object)
@ -1182,6 +1200,18 @@ have been replaced by constants."
(setcar form (car new-form))
(setcdr form (cdr new-form))))
(eshell-do-eval form synchronous-p))
((memq (car form) '(and or))
(eshell-manipulate form (format-message "evaluating %s form" (car form))
(let* ((result (eshell-do-eval (car args) synchronous-p))
(value (cadr result)))
(if (or (null (cdr args))
(if (eq (car form) 'or) value (not value)))
;; If this is the last sub-form or we short-circuited,
;; just return the result.
result
;; Otherwise, remove this sub-form and re-evaluate.
(setcdr form (cdr args))
(eshell-do-eval form synchronous-p)))))
((eq (car form) 'setcar)
(setcar (cdr args) (eshell-do-eval (cadr args) synchronous-p))
(eval form))

30
test/lisp/eshell/esh-cmd-tests.el
View file

@ -176,6 +176,21 @@ bug#59469."
(eshell-match-command-output "[ foo = bar ] && echo hi"
"\\`\\'")))
(ert-deftest esh-cmd-test/and-operator/output ()
"Test output with logical && operator."
(skip-unless (executable-find "sh"))
(with-temp-eshell
;; Direct commands
(eshell-match-command-output "sh -c 'echo one; exit 1' && echo two"
"\\`one\n\\'")
(eshell-match-command-output "echo one && echo two"
"\\`one\ntwo\n\\'")
;; Subcommands
(eshell-match-command-output "{ sh -c 'echo one; exit 1' } && echo two"
"\\`one\n\\'")
(eshell-match-command-output "{ echo one } && echo two"
"\\`one\ntwo\n\\'")))
(ert-deftest esh-cmd-test/or-operator ()
"Test logical || operator."
(skip-unless (executable-find "["))
@ -185,6 +200,21 @@ bug#59469."
(eshell-match-command-output "[ foo = bar ] || echo hi"
"hi\n")))
(ert-deftest esh-cmd-test/or-operator/output ()
"Test output with logical || operator."
(skip-unless (executable-find "sh"))
(with-temp-eshell
;; Direct commands
(eshell-match-command-output "sh -c 'echo one; exit 1' || echo two"
"\\`one\ntwo\n\\'")
(eshell-match-command-output "echo one || echo two"
"\\`one\n\\'")
;; Subcommands
(eshell-match-command-output "{ sh -c 'echo one; exit 1' } || echo two"
"\\`one\ntwo\n\\'")
(eshell-match-command-output "{ echo one } || echo two"
"\\`one\n\\'")))
;; Pipelines