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
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
|
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2015 Andy Wingo <wingo@igalia.com>
;;; Copyright © 2017 Mathieu Othacehe <m.othacehe@gmail.com>
;;; Copyright © 2017, 2018 Clément Lassieur <clement@lassieur.org>
;;; Copyright © 2021 Xinglu Chen <public@yoctocell.xyz>
;;; Copyright © 2021 Maxim Cournoyer <maxim.cournoyer@gmail.com>
;;;
;;; 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 (gnu services configuration)
#:use-module (guix packages)
#:use-module (guix records)
#:use-module (guix gexp)
#:use-module ((guix utils) #:select (source-properties->location))
#:use-module ((guix diagnostics) #:select (location-file))
#:use-module ((guix modules) #:select (file-name->module-name))
#:autoload (texinfo) (texi-fragment->stexi)
#:autoload (texinfo serialize) (stexi->texi)
#:use-module (ice-9 match)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-34)
#:use-module (srfi srfi-35)
#:export (configuration-field
configuration-field-name
configuration-field-type
configuration-missing-field
configuration-field-error
configuration-field-serializer
configuration-field-getter
configuration-field-default-value-thunk
configuration-field-documentation
configuration-error?
define-configuration
define-configuration/no-serialization
no-serialization
serialize-configuration
define-maybe
define-maybe/no-serialization
validate-configuration
generate-documentation
configuration->documentation
empty-serializer
serialize-package))
;;; Commentary:
;;;
;;; Syntax for creating Scheme bindings to complex configuration files.
;;;
;;; Code:
(define-condition-type &configuration-error &error
configuration-error?)
(define (configuration-error message)
(raise (condition (&message (message message))
(&configuration-error))))
(define (configuration-field-error field val)
(configuration-error
(format #f "Invalid value for field ~a: ~s" field val)))
(define (configuration-missing-field kind field)
(configuration-error
(format #f "~a configuration missing required field ~a" kind field)))
(define (configuration-no-default-value kind field)
(configuration-error
(format #f "The field `~a' of the `~a' configuration record \
does not have a default value" field kind)))
(define-record-type* <configuration-field>
configuration-field make-configuration-field configuration-field?
(name configuration-field-name)
(type configuration-field-type)
(getter configuration-field-getter)
(predicate configuration-field-predicate)
(serializer configuration-field-serializer)
(default-value-thunk configuration-field-default-value-thunk)
(documentation configuration-field-documentation))
(define (serialize-configuration config fields)
#~(string-append
#$@(map (lambda (field)
((configuration-field-serializer field)
(configuration-field-name field)
((configuration-field-getter field) config)))
fields)))
(define (validate-configuration config fields)
(for-each (lambda (field)
(let ((val ((configuration-field-getter field) config)))
(unless ((configuration-field-predicate field) val)
(configuration-field-error
(configuration-field-name field) val))))
fields))
(define-syntax-rule (id ctx parts ...)
"Assemble PARTS into a raw (unhygienic) identifier."
(datum->syntax ctx (symbol-append (syntax->datum parts) ...)))
(define (define-maybe-helper serialize? prefix syn)
(syntax-case syn ()
((_ stem)
(with-syntax
((stem? (id #'stem #'stem #'?))
(maybe-stem? (id #'stem #'maybe- #'stem #'?))
(serialize-stem (if prefix
(id #'stem prefix #'serialize- #'stem)
(id #'stem #'serialize- #'stem)))
(serialize-maybe-stem (if prefix
(id #'stem prefix #'serialize-maybe- #'stem)
(id #'stem #'serialize-maybe- #'stem))))
#`(begin
(define (maybe-stem? val)
(or (eq? val 'disabled) (stem? val)))
#,@(if serialize?
(list #'(define (serialize-maybe-stem field-name val)
(if (stem? val)
(serialize-stem field-name val)
"")))
'()))))))
(define-syntax define-maybe
(lambda (x)
(syntax-case x (no-serialization prefix)
((_ stem (no-serialization))
(define-maybe-helper #f #f #'(_ stem)))
((_ stem (prefix serializer-prefix))
(define-maybe-helper #t #'serializer-prefix #'(_ stem)))
((_ stem)
(define-maybe-helper #t #f #'(_ stem))))))
(define-syntax-rule (define-maybe/no-serialization stem)
(define-maybe stem (no-serialization)))
(define (define-configuration-helper serialize? serializer-prefix syn)
(syntax-case syn ()
((_ stem (field (field-type def ...) doc custom-serializer ...) ...)
(with-syntax (((field-getter ...)
(map (lambda (field)
(id #'stem #'stem #'- field))
#'(field ...)))
((field-predicate ...)
(map (lambda (type)
(id #'stem type #'?))
#'(field-type ...)))
((field-default ...)
(map (match-lambda
((field-type default-value)
default-value)
((field-type)
;; Quote `undefined' to prevent a possibly
;; unbound warning.
(syntax 'undefined)))
#'((field-type def ...) ...)))
((field-serializer ...)
(map (lambda (type custom-serializer)
(and serialize?
(match custom-serializer
((serializer)
serializer)
(()
(if serializer-prefix
(id #'stem
serializer-prefix
#'serialize- type)
(id #'stem #'serialize- type))))))
#'(field-type ...)
#'((custom-serializer ...) ...))))
#`(begin
(define-record-type* #,(id #'stem #'< #'stem #'>)
#,(id #'stem #'% #'stem)
#,(id #'stem #'make- #'stem)
#,(id #'stem #'stem #'?)
(%location #,(id #'stem #'stem #'-location)
(default (and=> (current-source-location)
source-properties->location))
(innate))
#,@(map (lambda (name getter def)
(if (eq? (syntax->datum def) (quote 'undefined))
#`(#,name #,getter)
#`(#,name #,getter (default #,def))))
#'(field ...)
#'(field-getter ...)
#'(field-default ...)))
(define #,(id #'stem #'stem #'-fields)
(list (configuration-field
(name 'field)
(type 'field-type)
(getter field-getter)
(predicate field-predicate)
(serializer field-serializer)
(default-value-thunk
(lambda ()
(display '#,(id #'stem #'% #'stem))
(if (eq? (syntax->datum field-default)
'undefined)
(configuration-no-default-value
'#,(id #'stem #'% #'stem) 'field)
field-default)))
(documentation doc))
...))
(define-syntax-rule (stem arg (... ...))
(let ((conf (#,(id #'stem #'% #'stem) arg (... ...))))
(validate-configuration conf
#,(id #'stem #'stem #'-fields))
conf)))))))
(define no-serialization ;syntactic keyword for 'define-configuration'
'(no serialization))
(define-syntax define-configuration
(lambda (s)
(syntax-case s (no-serialization prefix)
((_ stem (field (field-type def ...) doc custom-serializer ...) ...
(no-serialization))
(define-configuration-helper
#f #f #'(_ stem (field (field-type def ...) doc custom-serializer ...)
...)))
((_ stem (field (field-type def ...) doc custom-serializer ...) ...
(prefix serializer-prefix))
(define-configuration-helper
#t #'serializer-prefix #'(_ stem (field (field-type def ...)
doc custom-serializer ...)
...)))
((_ stem (field (field-type def ...) doc custom-serializer ...) ...)
(define-configuration-helper
#t #f #'(_ stem (field (field-type def ...) doc custom-serializer ...)
...))))))
(define-syntax-rule (define-configuration/no-serialization
stem (field (field-type def ...)
doc custom-serializer ...) ...)
(define-configuration stem (field (field-type def ...)
doc custom-serializer ...) ...
(no-serialization)))
(define (empty-serializer field-name val) "")
(define serialize-package empty-serializer)
;; A little helper to make it easier to document all those fields.
(define (generate-documentation documentation documentation-name)
(define (str x) (object->string x))
(define (package->symbol package)
"Return the first symbol name of a package that matches PACKAGE, else #f."
(let* ((module (file-name->module-name
(location-file (package-location package))))
(symbols (filter-map
identity
(module-map (lambda (symbol var)
(and (equal? package (variable-ref var))
symbol))
(resolve-module module)))))
(if (null? symbols)
#f
(first symbols))))
(define (generate configuration-name)
(match (assq-ref documentation configuration-name)
((fields . sub-documentation)
`((deftp (% (category "Data Type") (name ,(str configuration-name)))
(para "Available " (code ,(str configuration-name)) " fields are:")
(table
(% (formatter (asis)))
,@(map
(lambda (f)
(let ((field-name (configuration-field-name f))
(field-type (configuration-field-type f))
(field-docs (cdr (texi-fragment->stexi
(configuration-field-documentation f))))
(default (catch #t
(configuration-field-default-value-thunk f)
(lambda _ '%invalid))))
(define (show-default? val)
(or (string? val) (number? val) (boolean? val)
(package? val)
(and (symbol? val) (not (eq? val '%invalid)))
(and (list? val) (and-map show-default? val))))
(define (show-default val)
(cond
((package? val)
(symbol->string (package->symbol val)))
(else (str val))))
`(entry (% (heading
(code ,(str field-name))
,@(if (show-default? default)
`(" (default: "
(code ,(show-default default)) ")")
'())
" (type: " ,(str field-type) ")"))
(para ,@field-docs)
,@(append-map
generate
(or (assq-ref sub-documentation field-name)
'())))))
fields)))))))
(stexi->texi `(*fragment* . ,(generate documentation-name))))
(define (configuration->documentation configuration-symbol)
"Take CONFIGURATION-SYMBOL, the symbol corresponding to the name used when
defining a configuration record with DEFINE-CONFIGURATION, and output the
Texinfo documentation of its fields."
;; This is helper for a simple, straight-forward application of
;; GENERATE-DOCUMENTATION.
(let ((fields-getter (module-ref (current-module)
(symbol-append configuration-symbol
'-fields))))
(display (generate-documentation `((,configuration-symbol ,fields-getter))
configuration-symbol))))
|