From 64438d976f496f971df4f011f55881f4c2c2a568 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Taylan=20Ulrich=20Bay=C4=B1rl=C4=B1/Kammer?= Date: Sun, 25 Oct 2015 23:01:49 +0200 Subject: [PATCH] Add packages/shell-quasiquote/ --- packages/shell-quasiquote/shell-quasiquote.el | 154 ++++++++++++++++++ 1 file changed, 154 insertions(+) create mode 100644 packages/shell-quasiquote/shell-quasiquote.el diff --git a/packages/shell-quasiquote/shell-quasiquote.el b/packages/shell-quasiquote/shell-quasiquote.el new file mode 100644 index 000000000..1d08defba --- /dev/null +++ b/packages/shell-quasiquote/shell-quasiquote.el @@ -0,0 +1,154 @@ +;;; shell-quasiquote.el --- Turn s-expressions into shell command strings. + +;; Copyright (C) 2015 Free Software Foundation, Inc. + +;; Author: Taylan Ulrich Bayırlı/Kammer +;; Keywords: extensions, unix + +;; This program is free software; you can redistribute it and/or modify +;; it under the terms of the GNU General Public License as published by +;; the Free Software Foundation, either version 3 of the License, or +;; (at your option) any later version. + +;; This program is distributed in the hope that it will be useful, +;; but WITHOUT ANY WARRANTY; without even the implied warranty of +;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +;; GNU General Public License for more details. + +;; You should have received a copy of the GNU General Public License +;; along with this program. If not, see . + +;;; Commentary: + +;; "Shell quasiquote" -- turn s-expressions into POSIX shell command strings. +;; +;; Shells other than POSIX sh are not supported. +;; +;; Quoting is automatic and safe against injection. +;; +;; (let ((file1 "file one") +;; (file2 "file two")) +;; (shqq (cp -r ,file1 ,file2 "My Files"))) +;; => "cp -r 'file one' 'file two' 'My Files'" +;; +;; You can splice many arguments into place with ,@foo. +;; +;; (let ((files (list "file one" "file two"))) +;; (shqq (cp -r ,@files "My Files"))) +;; => "cp -r 'file one' 'file two' 'My Files'" +;; +;; Note that the quoting disables a variety of shell expansions like ~/foo, +;; $ENV_VAR, and e.g. {x..y} in GNU Bash. +;; +;; You can use ,,foo to escape the quoting. +;; +;; (let ((files "file1 file2")) +;; (shqq (cp -r ,,files "My Files"))) +;; => "cp -r file1 file2 'My Files'" +;; +;; And ,,@foo to splice and escape quoting. +;; +;; (let* ((arglist '("-x 'foo bar' -y baz")) +;; (arglist (append arglist '("-z 'qux fux'")))) +;; (shqq (command ,,@arglist))) +;; => "command -x 'foo bar' -y baz -z 'qux fux'" +;; +;; Neat, eh? + + +;;; Code: + +;;; We don't use `shell-quote-argument' because it doesn't provide any safety +;;; guarantees, and this quotes shell keywords as well. +(defun shqq--quote-string (string) + (concat "'" (replace-regexp-in-string "'" "'\\\\''" string) "'")) + +(defun shqq--atom-to-string (atom) + (cond + ((symbolp atom) (symbol-name atom)) + ((stringp atom) atom) + ((numberp atom) (number-to-string atom)) + (t (error "Bad shqq atom: %S" atom)))) + +(defun shqq--quote-atom (atom) + (shqq--quote-string (shqq--atom-to-string atom))) + +(defun shqq--match-comma (form) + "Matches FORM against ,foo i.e. (\, foo) and returns foo. +Returns nil if FORM didn't match. You can't disambiguate between +FORM matching ,nil and not matching." + (if (and (consp form) + (eq '\, (car form)) + (consp (cdr form)) + (null (cddr form))) + (cadr form))) + +(defun shqq--match-comma2 (form) + "Matches FORM against ,,foo i.e. (\, (\, foo)) and returns foo. +Returns nil if FORM didn't match. You can't disambiguate between +FORM matching ,,nil and not matching." + (if (and (consp form) + (eq '\, (car form)) + (consp (cdr form)) + (null (cddr form))) + (shqq--match-comma (cadr form)))) + + +(defmacro shqq (parts) + "First, PARTS is turned into a list of strings. For this, +every element of PARTS must be one of: + +- a symbol, evaluating to its name, + +- a string, evaluating to itself, + +- a number, evaluating to its decimal representation, + +- \",expr\", where EXPR must evaluate to an atom that will be + interpreted according to the previous rules, + +- \",@list-expr\", where LIST-EXPR must evaluate to a list whose + elements will each be interpreted like the EXPR in an \",EXPR\" + form, and spliced into the list of strings, + +- \",,expr\", where EXPR is interpreted like in \",expr\", + +- or \",,@expr\", where EXPR is interpreted like in \",@expr\". + +In the resulting list of strings, all elements except the ones +resulting from \",,expr\" and \",,@expr\" forms are quoted for +shell grammar. + +Finally, the resulting list of strings is concatenated with +separating spaces." + (let ((parts + (mapcar + (lambda (part) + (cond + ((atom part) (shqq--quote-atom part)) + ;; We use the match-comma helpers because pcase can't match ,foo. + (t (pcase part + ;; ,,foo i.e. (, (, foo)) + ((pred shqq--match-comma2) + (shqq--match-comma2 part)) + ;; ,,@foo i.e. (, (,@ foo)) + ((and (pred shqq--match-comma) + (let `,@,form (shqq--match-comma part))) + `(mapconcat #'identity ,form " ")) + ;; ,foo + ;; Insert redundant 'and x' to work around debbugs#18554. + ((and x (pred shqq--match-comma)) + `(shqq--quote-atom ,(shqq--match-comma part))) + ;; ,@foo + (`,@,form + `(mapconcat #'shqq--quote-atom ,form " ")) + (_ + (error "Bad shqq part: %S" part)))))) + parts))) + `(mapconcat #'identity (list ,@parts) " "))) + +(provide 'shell-quasiquote) +;; Local Variables: +;; coding: utf-8 +;; End: +;;; shell-quasiquote.el ends here -- 2.39.2