aboutsummaryrefslogtreecommitdiff
path: root/guix/scripts/repl.scm
blob: 02169e80042c5fdc745f6c71d50f3445adb19709 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2018 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 scripts repl)
  #:use-module (guix ui)
  #:use-module (guix scripts)
  #:use-module (guix utils)
  #:use-module (guix packages)
  #:use-module (gnu packages)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-37)
  #:use-module (ice-9 match)
  #:use-module (rnrs bytevectors)
  #:autoload   (system repl repl) (start-repl)
  #:autoload   (system repl server)
                  (make-tcp-server-socket make-unix-domain-server-socket)
  #:export (machine-repl
            guix-repl))

;;; Commentary:
;;;
;;; This command provides a Guile REPL

(define %default-options
  `((type . guile)))

(define %options
  (list (option '(#\h "help") #f #f
                (lambda args
                  (show-help)
                  (exit 0)))
        (option '(#\V "version") #f #f
                (lambda args
                  (show-version-and-exit "guix repl")))
        (option '(#\t "type") #t #f
                (lambda (opt name arg result)
                  (alist-cons 'type (string->symbol arg) result)))
        (option '("listen") #t #f
                (lambda (opt name arg result)
                  (alist-cons 'listen arg result)))))


(define (show-help)
  (display (G_ "Usage: guix repl [OPTIONS...]
Start a Guile REPL in the Guix execution environment.\n"))
  (display (G_ "
  -t, --type=TYPE        start a REPL of the given TYPE"))
  (newline)
  (display (G_ "
  -h, --help             display this help and exit"))
  (display (G_ "
  -V, --version          display version information and exit"))
  (newline)
  (show-bug-report-information))

(define (self-quoting? x)
  "Return #t if X is self-quoting."
  (letrec-syntax ((one-of (syntax-rules ()
                            ((_) #f)
                            ((_ pred rest ...)
                             (or (pred x)
                                 (one-of rest ...))))))
    (one-of symbol? string? pair? null? vector?
            bytevector? number? boolean?)))

(define user-module
  ;; Module where we execute user code.
  (let ((module (resolve-module '(guix-user) #f #f #:ensure #t)))
    (beautify-user-module! module)
    module))

(define* (machine-repl #:optional
                       (input (current-input-port))
                       (output (current-output-port)))
  "Run a machine-usable REPL over ports INPUT and OUTPUT.

The protocol of this REPL is meant to be machine-readable and provides proper
support to represent multiple-value returns, exceptions, objects that lack a
read syntax, and so on.  As such it is more convenient and robust than parsing
Guile's REPL prompt."
  (define (value->sexp value)
    (if (self-quoting? value)
        `(value ,value)
        `(non-self-quoting ,(object-address value)
                           ,(object->string value))))

  (write `(repl-version 0 0) output)
  (newline output)
  (force-output output)

  (let loop ()
    (match (read input)
      ((? eof-object?) #t)
      (exp
       (catch #t
         (lambda ()
           (let ((results (call-with-values
                              (lambda ()

                                (primitive-eval exp))
                            list)))
             (write `(values ,@(map value->sexp results))
                    output)
             (newline output)
             (force-output output)))
         (lambda (key . args)
           (write `(exception ,key ,@(map value->sexp args)))
           (newline output)
           (force-output output)))
       (loop)))))

(define (call-with-connection spec thunk)
  "Dynamically-bind the current input and output ports according to SPEC and
call THUNK."
  (if (not spec)
      (thunk)

      ;; Note: the "PROTO:" prefix in SPEC is here so that we can eventually
      ;; parse things like "fd:123" in a non-ambiguous way.
      (match (string-index spec #\:)
        (#f
         (leave (G_ "~A: invalid listen specification~%") spec))
        (index
         (let ((protocol (string-take spec index))
               (address  (string-drop spec (+ index 1))))
           (define socket
             (match protocol
               ("tcp"
                (make-tcp-server-socket #:port (string->number address)))
               ("unix"
                (make-unix-domain-server-socket #:path address))
               (_
                (leave (G_ "~A: unsupported protocol family~%")
                       protocol))))

           (listen socket 10)
           (let loop ()
             (match (accept socket)
               ((connection . address)
                (if (= AF_UNIX (sockaddr:fam address))
                    (info (G_ "accepted connection~%"))
                    (info (G_ "accepted connection from ~a~%")
                          (inet-ntop (sockaddr:fam address)
                                     (sockaddr:addr address))))
                (dynamic-wind
                  (const #t)
                  (lambda ()
                    (parameterize ((current-input-port connection)
                                   (current-output-port connection))
                      (thunk)))
                  (lambda ()
                    (false-if-exception (close-port connection))
                    (info (G_ "connection closed~%"))))))
             (loop)))))))


(define (guix-repl . args)
  (define opts
    ;; Return the list of package names.
    (args-fold* args %options
                (lambda (opt name arg result)
                  (leave (G_ "~A: unrecognized option~%") name))
                (lambda (arg result)
                  (leave (G_ "~A: extraneous argument~%") arg))
                %default-options))

  (with-error-handling
    (let ((type (assoc-ref opts 'type)))
      (call-with-connection (assoc-ref opts 'listen)
        (lambda ()
          (case type
            ((guile)
             (save-module-excursion
              (lambda ()
                (set-current-module user-module)
                (and=> (getenv "HOME")
                       (lambda (home)
                         (let ((guile (string-append home "/.guile")))
                           (when (file-exists? guile)
                             (load guile)))))
                ;; Do not exit repl on SIGINT.
                ((@@ (ice-9 top-repl) call-with-sigint)
                 (lambda ()
                   (start-repl))))))
            ((machine)
             (machine-repl))
            (else
             (leave (G_ "~a: unknown type of REPL~%") type))))))))

;; Local Variables:
;; eval: (put 'call-with-connection 'scheme-indent-function 1)
;; End: