-
Notifications
You must be signed in to change notification settings - Fork 344
/
haskell-string.el
220 lines (179 loc) · 10 KB
/
haskell-string.el
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
212
213
214
215
216
217
218
219
220
;;; haskell-string.el --- Haskell related string utilities -*- lexical-binding: t -*-
;; Copyright (C) 2013 Herbert Valerio Riedel
;; Author: Herbert Valerio Riedel <[email protected]>
;; This file is not part of GNU Emacs.
;; This file 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 file 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:
;;; Todo:
;; - write ERT tests
;;; Code:
(require 'cl-lib)
(defun haskell-string-trim (string)
"Remove whitespace around STRING.
A Whitespace character is defined in the Haskell Report as follows
whitechar -> newline | vertab | space | tab | uniWhite
newline -> return linefeed | return | linefeed | formfeed
uniWhite -> any Unicode character defined as whitespace
Note: The implementation currently only supports ASCII
white-space characters, i.e. the implemention doesn't
consider uniWhite."
(let ((s1 (if (string-match "[\t\n\v\f\r ]+\\'" string) (replace-match "" t t string) string)))
(if (string-match "\\`[\t\n\v\f\r ]+" s1) (replace-match "" t t s1) s1)))
(defun haskell-string-only-spaces-p (string)
"Return t if STRING contains only whitespace (or is empty)."
(string= "" (haskell-string-trim string)))
(defun haskell-string-take (string n)
"Return (up to) N character length prefix of STRING."
(substring string 0 (min (length string) n)))
(defconst haskell-string-literal-encode-ascii-array
[ "\\NUL" "\\SOH" "\\STX" "\\ETX" "\\EOT" "\\ENQ" "\\ACK" "\\a" "\\b" "\\t" "\\n" "\\v" "\\f" "\\r" "\\SO" "\\SI" "\\DLE" "\\DC1" "\\DC2" "\\DC3" "\\DC4" "\\NAK" "\\SYN" "\\ETB" "\\CAN" "\\EM" "\\SUB" "\\ESC" "\\FS" "\\GS" "\\RS" "\\US" " " "!" "\\\"" "#" "$" "%" "&" "'" "(" ")" "*" "+" "," "-" "." "/" "0" "1" "2" "3" "4" "5" "6" "7" "8" "9" ":" ";" "<" "=" ">" "?" "@" "A" "B" "C" "D" "E" "F" "G" "H" "I" "J" "K" "L" "M" "N" "O" "P" "Q" "R" "S" "T" "U" "V" "W" "X" "Y" "Z" "[" "\\\\" "]" "^" "_" "`" "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l" "m" "n" "o" "p" "q" "r" "s" "t" "u" "v" "w" "x" "y" "z" "{" "|" "}" "~" "\\DEL" ]
"Array of encodings for 7-bit ASCII character points indexed by ASCII value.")
(defun haskell-string-literal-encode (str &optional no-quotes)
"Encode STR according Haskell escape rules using 7-bit ASCII representation.
The serialization has been implemented to closely match the
behaviour of GHC's Show instance for Strings.
If NO-QUOTES is non-nil, omit wrapping result in quotes.
This is the dual operation to `haskell-string-literal-decode'."
(let ((lastc -1))
(let ((encode (lambda (c)
(let ((lc lastc))
(setq lastc c)
(if (>= c 128) ;; if non-ASCII code point
(format "\\%d" c)
;; else, for ASCII code points
(if (or (and (= lc 14) (= c ?H)) ;; "\SO\&H"
(and (>= lc 128) (>= c ?0) (<= c ?9))) ;; "\123\&4"
(concat "\\&" (aref haskell-string-literal-encode-ascii-array c))
(aref haskell-string-literal-encode-ascii-array c)
))))))
(if no-quotes
(mapconcat encode str "")
(concat "\"" (mapconcat encode str "") "\"")))))
(defconst haskell-string-literal-escapes-regexp
(concat "[\\]\\(?:"
(regexp-opt (append
(mapcar (lambda (c) (format "%c" c))
"abfnrtv\\\"'&") ;; "charesc" escape sequences
(mapcar (lambda (c) (format "^%c" c))
"ABCDEFGHIJKLMNOPQRSTUVWXYZ@[\\]^_") ;; "cntrl" escape sequences
(mapcar (lambda (s) (format "%s" s))
(split-string "NUL SOH STX ETX EOT ENQ ACK BEL BS HT LF VT FF CR
SO SI DLE DC1 DC2 DC3 DC4 NAK SYN ETB CAN EM SUB ESC
FS GS RS US SP DEL")))) ;; "ascii" (w\o "cntrl") escape sequences
"\\|" "[\t\n\v\f\r ]+[\\]" ;; whitespace gaps
"\\|" "[0-9]+" ;; decimal escape sequence
"\\|" "o[0-7]+" ;; octal escape sequence
"\\|" "x[0-9a-f]+" ;; hex escape sequence
"\\)?") ;; everything else is an invalid escape sequence
"Regexp for matching escape codes in string literals.
See Haskell Report Sect 2.6,
URL `http://www.haskell.org/onlinereport/haskell2010/haskellch2.html#x7-200002.6',
for more details.")
(defconst haskell-string-literal-decode1-table
(let ((h (make-hash-table :test 'equal)))
(mapc (lambda (c) (puthash (concat "\\" (car c)) (cdr c) h))
'(;; ascii-escapes
("NUL" . "\x00") ("SOH" . "\x01") ("STX" . "\x02") ("ETX" . "\x03") ("EOT" . "\x04") ("ENQ" . "\x05")
("ACK" . "\x06") ("BEL" . "\x07") ("BS" . "\x08") ("HT" . "\x09") ("LF" . "\x0a") ("VT" . "\x0b")
("FF" . "\x0c") ("CR" . "\x0d") ("SO" . "\x0e") ("SI" . "\x0f") ("DLE" . "\x10") ("DC1" . "\x11")
("DC2" . "\x12") ("DC3" . "\x13") ("DC4" . "\x14") ("NAK" . "\x15") ("SYN" . "\x16") ("ETB" . "\x17")
("CAN" . "\x18") ("EM" . "\x19") ("SUB" . "\x1a") ("ESC" . "\x1b") ("FS" . "\x1c") ("GS" . "\x1d")
("RS" . "\x1e") ("US" . "\x1f") ("SP" . "\x20") ("DEL" . "\x7f" )
;; C-compatible single-char escape sequences
("a" . "\x07") ("b" . "\x08") ("f" . "\x0c") ("n" . "\x0a") ("r" . "\x0d") ("t" . "\x09") ("v" . "\x0b")
;; trivial escapes
("\\" . "\\") ("\"" . "\"") ("'" . "'")
;; "empty" escape
("&" . "")))
h)
"Hash table containing irregular escape sequences and their decoded strings.
Used by `haskell-string-literal-decode1'.")
(defun haskell-string-literal-decode1 (l)
"Decode a single string literal escape sequence.
L must contain exactly one escape sequence.
This is an internal function used by `haskell-string-literal-decode'."
(let ((case-fold-search nil))
(cond
((gethash l haskell-string-literal-decode1-table))
((string-match "\\`[\\][0-9]+\\'" l) (char-to-string (string-to-number (substring l 1) 10)))
((string-match "\\`[\\]x[[:xdigit:]]+\\'" l) (char-to-string (string-to-number (substring l 2) 16)))
((string-match "\\`[\\]o[0-7]+\\'" l) (char-to-string (string-to-number (substring l 2) 8)))
((string-match "\\`[\\]\\^[@-_]\\'" l) (char-to-string (- (aref l 2) ?@))) ;; "cntrl" escapes
((string-match "\\`[\\][\t\n\v\f\r ]+[\\]\\'" l) "") ;; whitespace gap
(t (error "Invalid escape sequence")))))
(defun haskell-string-literal-decode (estr &optional no-quotes)
"Decode a Haskell string-literal.
If NO-QUOTES is nil, ESTR must be surrounded by quotes.
This is the dual operation to `haskell-string-literal-encode'."
(if (and (not no-quotes)
(string-match-p "\\`\"[^\\\"[:cntrl:]]*\"\\'" estr))
(substring estr 1 -1) ;; optimized fast-path for trivial strings
(let ((s (if no-quotes ;; else: do general decoding
estr
(if (string-match-p "\\`\".*\"\\'" estr)
(substring estr 1 -1)
(error "String literal must be delimited by quotes"))))
(case-fold-search nil))
(replace-regexp-in-string haskell-string-literal-escapes-regexp #'haskell-string-literal-decode1 s t t))))
(defun haskell-string-ellipsize (string n)
"Return STRING truncated to (at most) N characters.
If truncation occurred, last character in string is replaced by `…'.
See also `haskell-string-take'."
(cond
((<= (length string) n) string) ;; no truncation needed
((< n 1) "")
(t (concat (substring string 0 (1- n)) "…"))))
(defun haskell-string-chomp (str)
"Chomp leading and tailing whitespace from STR."
(while (string-match "\\`\n+\\|^\\s-+\\|\\s-+$\\|\n+\\'"
str)
(setq str (replace-match "" t t str)))
str)
(defun haskell-string-split-to-lines (str)
"Split STR to lines and return a list of strings with preceding and
succeding space removed."
(when (stringp str)
(cl-mapcar #'haskell-string-chomp (split-string str "\n"))))
(defun haskell-string-trim-prefix (prefix str)
"If PREFIX is prefix of STR, the string is trimmed."
(when (and (stringp prefix)
(stringp str))
(if (string-prefix-p prefix str)
(substring str (length prefix)))))
(defun haskell-string-trim-suffix (suffix str)
"If SUFFIX is suffix of STR, the string is trimmed."
(when (and (stringp suffix)
(stringp str))
(if (string-suffix-p suffix str)
(substring str 0 (* -1 (length suffix))))))
(defun haskell-string-drop-qualifier (ident)
"Drop qualifier from given identifier IDENT.
If the identifier is not qualified return it unchanged."
(or (and (string-match "^\\([^.]*\\.\\)*\\(?1:[^.]+\\)$" ident)
(match-string 1 ident))
ident))
(defun haskell-mode-message-line (str)
"Echo STR in mini-buffer.
Given string is shrinken to single line, multiple lines just
disturbs the programmer."
(unless (active-minibuffer-window)
(message "%s" (haskell-mode-one-line str (frame-width)))))
(defun haskell-mode-one-line (str &optional width)
"Try to fit STR as much as possible on one line according to given WIDTH."
(unless width
(setq width (length str)))
(let* ((long-line (replace-regexp-in-string "\n" " " str))
(condensed (replace-regexp-in-string
" +" " " (haskell-string-trim long-line))))
(truncate-string-to-width condensed width nil nil "…")))
(provide 'haskell-string)
;;; haskell-string.el ends here