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
208
209
210
211
|
;;; Chickadee Game Toolkit
;;; Copyright © 2021 David Thompson <dthompson2@worcester.edu>
;;;
;;; Chickadee 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.
;;;
;;; Chickadee 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
;;; <http://www.gnu.org/licenses/>.
;;; Commentary
;;
;; Non-blocking terminal REPL with readline support.
;;
;;; Code:
(define-module (chickadee async-repl)
#:use-module (chickadee readline)
#:use-module (ice-9 format)
#:use-module (ice-9 match)
#:use-module (ice-9 rdelim)
#:use-module (ice-9 suspendable-ports)
#:use-module (srfi srfi-9)
#:use-module (system base language)
#:use-module (system repl common)
#:use-module (system repl debug)
#:export (make-async-repl
async-repl?
set-async-repl-debug!
start-async-debugger
start-async-repl
update-async-repl
close-async-repl))
;; Need to access some private API things.
(define run-repl* (@@ (system repl repl) run-repl*))
(define meta-command-token (@@ (system repl repl) meta-command-token))
(define %async-repl-prompt-tag (make-prompt-tag 'async-repl))
(define-record-type <async-repl>
(%make-async-repl input-port output-port)
async-repl?
(input-port async-repl-input-port)
(output-port async-repl-output-port)
(state async-repl-state set-async-repl-state!)
(cont async-repl-cont set-async-repl-cont!)
(debug async-repl-debug set-async-repl-debug!) )
(define (async-repl-waiting? repl)
(eq? (async-repl-state repl) 'waiting))
(define (async-repl-ready? repl)
(eq? (async-repl-state repl) 'ready))
(define (async-repl-send repl line)
(let ((output-port (async-repl-output-port repl)))
(add-readline-history line)
(display line output-port)
(newline output-port)
(force-output output-port)
(set-async-repl-state! repl 'ready)))
(define* (make-async-repl)
;; Need non-blocking I/O.
(install-suspendable-ports!)
;; Our REPL is not going to read from standard input, but instead
;; from the input port of a pipe. Readline will read from
;; standard input and then we will pass that text along through
;; the pipe to the REPL.
(match (pipe)
((input-port . output-port)
;; Set input port to non-blocking mode.
(let ((flags (fcntl input-port F_GETFL)))
(fcntl input-port F_SETFL (logior O_NONBLOCK flags)))
(%make-async-repl input-port output-port))))
(define* (async-repl-prompt repl prompt)
(install-readline-handler prompt
(lambda (line)
(async-repl-send repl line)
(remove-readline-handler)))
(set-async-repl-state! repl 'waiting)
;; Suspend the REPL until readline tells us that the user has
;; input a new line.
(abort-to-prompt %async-repl-prompt-tag (current-dynamic-state)))
(define (run-async-repl repl debug)
(define (repl-read repl*)
(define (flush-leading-whitespace)
(let ((c (peek-char)))
(cond
((eof-object? c) #t)
((char-whitespace? c)
(read-char)
(flush-leading-whitespace))
(else #t))))
(define (read-expression)
(when (char-ready?)
(flush-leading-whitespace)
(let ((c (peek-char)))
(cond
((eof-object? c) ; end of file
(read-char)
*unspecified*)
((eqv? c #\,) ; metacommand
(read-char) ; need to read first char
meta-command-token)
((eqv? c #\;) ; comment
(read-line)
*unspecified*)
(else ; read code using current language reader
(parameterize ((current-read-waiter
(lambda (port)
;; If 'read' doesn't complete because it
;; needs more input, then prompt the user
;; for another line.
(async-repl-prompt repl "...> "))))
(let ((read (language-reader (repl-language repl*))))
(read (current-input-port) (current-module)))))))))
;; Check if there are more expressions to process from the
;; previous user input before prompting for new input.
(if (char-ready?)
(read-expression)
(let ((debug (async-repl-debug repl)))
;; If we have debug info then it's time to launch a sub-REPL to
;; do the debugging.
(when debug
(set-async-repl-debug! repl #f)
(format #t "~a~%" (debug-error-message debug))
(format #t "Entering a new prompt. ")
(format #t "Type `,bt' for a backtrace or `,q' to continue.\n")
(run-async-repl repl debug))
(async-repl-prompt repl (repl-prompt repl*))
(read-expression))))
(define (error-string stack key args)
(call-with-output-string
(lambda (port)
(let ((frame (and (< 0 (vector-length stack)) (vector-ref stack 0))))
(print-exception port frame key args)))))
(define (on-error key . args)
(unless (eq? key 'quit)
(let* ((tag (and (pair? (fluid-ref %stacks))
(cdr (fluid-ref %stacks))))
(stack (narrow-stack->vector
(make-stack #t)
;; Cut three frames from the top of the stack:
;; make-stack, this one, and the throw handler.
3
;; Narrow the end of the stack to the most recent
;; start-stack.
tag
;; And one more frame, because %start-stack invoking
;; the start-stack thunk has its own frame too.
0 (and tag 1)))
(debug (make-debug stack 0 (error-string stack key args))))
;; We cannot jump right into the debugger REPL here because
;; there are C frames in the stack. This means that we cannot
;; resume any continuations we create via abort-to-prompt.
;; Instead, we record the debugger object so that the next
;; time the REPL reader procedure is called we can jump
;; straight into a debugging REPL.
(set-async-repl-debug! repl debug))))
;; The user can change the module from inside the REPL, and we don't
;; want that to affect the outside environment when the user exits
;; the REPL.
(save-module-excursion
(lambda ()
(let ((repl* (make-repl (current-language) debug)))
;; The REPL implementation allows custom procedures for the on-error
;; handler, but the validator only accepts symbols! So, we just
;; mutate the dang options ourselves.
(match (assq 'on-error (repl-options repl*))
((_ . spec)
(set-car! spec on-error)))
(run-repl* repl* repl-read)))))
(define* (start-async-repl repl #:optional (on-quit (const #t)))
(bind-readline-variable "blink-matching-paren" "on")
(parameterize ((current-input-port (async-repl-input-port repl)))
(define-syntax-rule (with-repl-prompt body ...)
(call-with-prompt %async-repl-prompt-tag
(lambda () body ...)
handler))
(define (handler k state)
(define (resume)
(with-repl-prompt (with-dynamic-state state k)))
(set-async-repl-cont! repl resume))
(with-repl-prompt
(run-async-repl repl #f)
(on-quit))))
(define (update-async-repl repl)
(when (and (async-repl-waiting? repl) (char-ready?))
(readline-read-char)
(when (async-repl-ready? repl)
(set-async-repl-state! repl 'running)
((async-repl-cont repl)))))
(define (close-async-repl repl)
(close-port (async-repl-input-port repl))
(close-port (async-repl-output-port repl))
(remove-readline-handler)
(newline))
|
