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
|
;;;; "Iedline.scm" SCM interface to readline library
;; Copyright (C) 1994, 1995 Free Software Foundation, Inc.
;;
;; This program is free software: you can redistribute it and/or modify
;; it under the terms of the GNU Lesser 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
;; Lesser General Public License for more details.
;;
;; You should have received a copy of the GNU Lesser General Public
;; License along with this program. If not, see
;; <http://www.gnu.org/licenses/>.
;; Author: Radey Shouman
;; Change both current-input-port and current-output-port to
;; allow line editing of input.
;; All output goes through a soft port in order to detect prompt
;; lines, i.e. lines unterminated by a newline.
(define (make-edited-line-port)
(let ; The prompt string we receive.
((prompt "")
; Hack to make readline overwrite the prompt we manually write.
; Notice that #\cr is being wrapped in #\soh and #\stx, respectively
; RL_PROMPT_START_IGNORE and RL_PROMPT_END_IGNORE (defined in
; <readline/readline.h>), to signal to readline that #\cr is
; invisible.
(prompt-hack (string #\soh #\cr #\stx))
; Concatenation of "prompt-hack" and "prompt", this is the actual
; prompt we send to readline.
(prompt-real "")
(outp (default-output-port))
(inp (default-input-port))
(strp (call-with-input-string "" identity)))
(make-soft-port
(vector (lambda (c)
(write-char c outp))
(lambda (s)
; Reverse-engineered assumption: string-write to this port will
; only be done in the following cases:
;
; - Empty string.
;
; - Printing repl results, in which case the string will
; always come linefeed-terminated.
;
; - Prompt printing, which will never be linefeed-terminated.
; The prompt string is immediately printed (manually),
; later, when GNU readline is called, a carriage return
; prepended to the same prompt string will cause it to
; write its prompt on top of the one we printed ourselves
; (therefore only one instance of the prompt string is
; actually visible to the interactive user). Presumably
; this is the result of kluging optional readline support
; on top of an existing prompting mechanism.
;
; -- astian
(display s outp)
(or (zero? (string-length s))
(eq? #\newline (string-ref s (- (string-length s) 1)))
(begin
(or (string=? s prompt)
(begin
(set! prompt s)
(set! prompt-real (string-append prompt-hack prompt))))
(force-output outp))))
(lambda ()
(force-output outp))
(lambda ()
(let tail ((c (read-char strp)))
(if (char? c) c
(let ((str (read-edited-line prompt-real)))
(if (string? str)
(let ((n (string-length str)))
(add-history str)
(vector-set-length! str (+ 1 n))
(string-set! str n #\newline)
(set! strp (call-with-input-string
str identity))
(tail (read-char strp)))
str)))))
#f)
open_both)))
(define line-editing
(let ((edit-port #f)
(oiport #f)
(ooport #f))
(lambda arg
(define past edit-port)
(cond ((null? arg))
((and (car arg) (not edit-port))
(set! edit-port (make-edited-line-port))
(set! oiport (set-current-input-port edit-port))
(set! ooport (set-current-output-port edit-port)))
(edit-port
(set-current-input-port oiport)
(set-current-output-port ooport)
(set! edit-port #f)))
past)))
(and
(if (provided? 'unix) (isatty? (current-input-port)) #t)
(eq? (current-input-port) (default-input-port))
(not (getenv "EMACS"))
(line-editing #t))
|
