diff options
| -rw-r--r-- | Makefile.am | 1 | ||||
| -rw-r--r-- | gnu/system/linux-initrd.scm | 4 | ||||
| -rw-r--r-- | guix/build/bournish.scm | 172 |
3 files changed, 176 insertions, 1 deletions
diff --git a/Makefile.am b/Makefile.am index 9620e600d1..9beeb9d564 100644 --- a/Makefile.am +++ b/Makefile.am @@ -98,6 +98,7 @@ MODULES = \ guix/build/gremlin.scm \ guix/build/emacs-utils.scm \ guix/build/graft.scm \ + guix/build/bournish.scm \ guix/search-paths.scm \ guix/packages.scm \ guix/import/utils.scm \ diff --git a/gnu/system/linux-initrd.scm b/gnu/system/linux-initrd.scm index f6bd84f02e..8ca74104fb 100644 --- a/gnu/system/linux-initrd.scm +++ b/gnu/system/linux-initrd.scm @@ -227,6 +227,7 @@ loaded at boot time in the order in which they appear." #~(begin (use-modules (gnu build linux-boot) (guix build utils) + (guix build bournish) ;add the 'bournish' meta-command (srfi srfi-26)) (with-output-to-port (%make-void-port "w") @@ -242,7 +243,8 @@ loaded at boot time in the order in which they appear." #:qemu-guest-networking? #$qemu-networking? #:volatile-root? '#$volatile-root?)) #:name "base-initrd" - #:modules '((guix build utils) + #:modules '((guix build bournish) + (guix build utils) (guix build syscalls) (gnu build linux-boot) (gnu build linux-modules) diff --git a/guix/build/bournish.scm b/guix/build/bournish.scm new file mode 100644 index 0000000000..4022796658 --- /dev/null +++ b/guix/build/bournish.scm @@ -0,0 +1,172 @@ +;;; GNU Guix --- Functional package management for GNU +;;; Copyright © 2016 Ludovic Courtès <ludo@gnu.org> +;;; +;;; This file is part of GNU Guix. +;;; +;;; GNU Guix 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. +;;; +;;; GNU Guix 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 GNU Guix. If not, see <http://www.gnu.org/licenses/>. + +(define-module (guix build bournish) + #:use-module (system base language) + #:use-module (system base compile) + #:use-module (system repl command) + #:use-module (system repl common) + #:use-module (ice-9 rdelim) + #:use-module (ice-9 match) + #:use-module (ice-9 ftw) + #:use-module (srfi srfi-1) + #:use-module (srfi srfi-26) + #:export (%bournish-language)) + +;;; Commentary: +;;; +;;; This is a super minimal Bourne-like shell language for Guile. It is meant +;;; to be used at the REPL as a rescue shell. In a way, this is to Guile what +;;; eshell is to Emacs. +;;; +;;; Code: + +(define (expand-variable str) + "Return STR or code to obtain the value of the environment variable STR +refers to." + ;; XXX: No support for "${VAR}". + (if (string-prefix? "$" str) + `(or (getenv ,(string-drop str 1)) "") + str)) + +(define* (display-tabulated lst + #:key (columns 3) + (column-width (/ 78 columns))) + "Display the list of string LST in COLUMNS columns of COLUMN-WIDTH +characters." + (define len (length lst)) + (define pad + (if (zero? (modulo len columns)) + 0 + columns)) + (define items-per-column + (quotient (+ len pad) columns)) + (define items (list->vector lst)) + + (let loop ((indexes (unfold (cut >= <> columns) + (cut * <> items-per-column) + 1+ + 0))) + (unless (>= (first indexes) items-per-column) + (for-each (lambda (index) + (let ((item (if (< index len) + (vector-ref items index) + ""))) + (display (string-pad-right item column-width)))) + indexes) + (newline) + (loop (map 1+ indexes))))) + +(define ls-command-implementation + ;; Run-time support procedure. + (case-lambda + (() + (display-tabulated (scandir "."))) + (files + (let ((files (filter (lambda (file) + (catch 'system-error + (lambda () + (lstat file)) + (lambda args + (let ((errno (system-error-errno args))) + (format (current-error-port) "~a: ~a~%" + file (strerror errno)) + #f)))) + files))) + (display-tabulated files))))) + +(define (ls-command . files) + `((@@ (guix build bournish) ls-command-implementation) ,@files)) + +(define (which-command program) + `(search-path ((@@ (guix build bournish) executable-path)) + ,program)) + +(define (cat-command file) + `(call-with-input-file ,file + (lambda (port) + ((@ (guix build utils) dump-port) port (current-output-port)) + *unspecified*))) + +(define (help-command . _) + (display "\ +Hello, this is Bournish, a minimal Bourne-like shell in Guile! + +The shell is good enough to navigate the file system and run commands but not +much beyond that. It is meant to be used as a rescue shell in the initial RAM +disk and is probably not very useful apart from that. It has a few built-in +commands such as 'ls' and 'cd'; it lacks globbing, pipes---everything.\n")) + +(define %not-colon (char-set-complement (char-set #\:))) +(define (executable-path) + "Return the search path for programs as a list." + (match (getenv "PATH") + (#f '()) + (str (string-tokenize str %not-colon)))) + +(define %commands + ;; Built-in commands. + `(("echo" ,(lambda strings `(list ,@strings))) + ("cd" ,(lambda (dir) `(chdir ,dir))) + ("pwd" ,(lambda () `(getcwd))) + ("rm" ,(lambda (file) `(delete-file ,file))) + ("cp" ,(lambda (source dest) `(copy-file ,source ,dest))) + ("help" ,help-command) + ("ls" ,ls-command) + ("which" ,which-command) + ("cat" ,cat-command))) + +(define (read-bournish port env) + "Read a Bournish expression from PORT, and return the corresponding Scheme +code as an sexp." + (match (string-tokenize (read-line port)) + ((command args ...) + (match (assoc command %commands) + ((command proc) ;built-in command + (apply proc (map expand-variable args))) + (#f + (let ((command (if (string-prefix? "\\" command) + (string-drop command 1) + command))) + `(system* ,command ,@(map expand-variable args)))))))) + +(define %bournish-language + (let ((scheme (lookup-language 'scheme))) + (make-language #:name 'bournish + #:title "Bournish" + #:reader read-bournish + #:compilers (language-compilers scheme) + #:decompilers (language-decompilers scheme) + #:evaluator (language-evaluator scheme) + #:printer (language-printer scheme) + #:make-default-environment + (language-make-default-environment scheme)))) + +;; XXX: ",L bournish" won't work unless we call our module (language bournish +;; spec), which is kinda annoying, so provide another meta-command. +(define-meta-command ((bournish guix) repl) + "bournish +Switch to the Bournish language." + (let ((current (repl-language repl))) + (format #t "Welcome to ~a, a minimal Bourne-like shell!~%To switch back, type `,L ~a'.\n" + (language-title %bournish-language) + (language-name current)) + (current-language %bournish-language) + (set! (repl-language repl) %bournish-language))) + +;;; bournish.scm ends here |