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21b679f6 LC |
1 | ;;; GNU Guix --- Functional package management for GNU |
2 | ;;; Copyright © 2014 Ludovic Courtès <ludo@gnu.org> | |
3 | ;;; | |
4 | ;;; This file is part of GNU Guix. | |
5 | ;;; | |
6 | ;;; GNU Guix is free software; you can redistribute it and/or modify it | |
7 | ;;; under the terms of the GNU General Public License as published by | |
8 | ;;; the Free Software Foundation; either version 3 of the License, or (at | |
9 | ;;; your option) any later version. | |
10 | ;;; | |
11 | ;;; GNU Guix is distributed in the hope that it will be useful, but | |
12 | ;;; WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | ;;; GNU General Public License for more details. | |
15 | ;;; | |
16 | ;;; You should have received a copy of the GNU General Public License | |
17 | ;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>. | |
18 | ||
19 | (define-module (guix gexp) | |
20 | #:use-module ((guix store) | |
21 | #:select (direct-store-path?)) | |
22 | #:use-module (guix monads) | |
23 | #:use-module ((guix derivations) | |
24 | #:select (derivation? derivation->output-path | |
25 | %guile-for-build derivation)) | |
26 | #:use-module (guix packages) | |
27 | #:use-module (srfi srfi-1) | |
28 | #:use-module (srfi srfi-9) | |
7560b00b | 29 | #:use-module (srfi srfi-9 gnu) |
21b679f6 LC |
30 | #:use-module (srfi srfi-26) |
31 | #:use-module (ice-9 match) | |
32 | #:export (gexp | |
33 | gexp? | |
34 | gexp->derivation | |
35 | gexp->file | |
36 | gexp->script)) | |
37 | ||
38 | ;;; Commentary: | |
39 | ;;; | |
40 | ;;; This module implements "G-expressions", or "gexps". Gexps are like | |
41 | ;;; S-expressions (sexps), with two differences: | |
42 | ;;; | |
43 | ;;; 1. References (un-quotations) to derivations or packages in a gexp are | |
667b2508 LC |
44 | ;;; replaced by the corresponding output file name; in addition, the |
45 | ;;; 'ungexp-native' unquote-like form allows code to explicitly refer to | |
46 | ;;; the native code of a given package, in case of cross-compilation; | |
21b679f6 LC |
47 | ;;; |
48 | ;;; 2. Gexps embed information about the derivations they refer to. | |
49 | ;;; | |
50 | ;;; Gexps make it easy to write to files Scheme code that refers to store | |
51 | ;;; items, or to write Scheme code to build derivations. | |
52 | ;;; | |
53 | ;;; Code: | |
54 | ||
55 | ;; "G expressions". | |
56 | (define-record-type <gexp> | |
667b2508 | 57 | (make-gexp references natives proc) |
21b679f6 LC |
58 | gexp? |
59 | (references gexp-references) ; ((DRV-OR-PKG OUTPUT) ...) | |
667b2508 | 60 | (natives gexp-native-references) ; ((DRV-OR-PKG OUTPUT) ...) |
21b679f6 LC |
61 | (proc gexp-proc)) ; procedure |
62 | ||
7560b00b LC |
63 | (define (write-gexp gexp port) |
64 | "Write GEXP on PORT." | |
65 | (display "#<gexp " port) | |
2cf0ea0d LC |
66 | |
67 | ;; Try to write the underlying sexp. Now, this trick doesn't work when | |
68 | ;; doing things like (ungexp-splicing (gexp ())) because GEXP's procedure | |
69 | ;; tries to use 'append' on that, which fails with wrong-type-arg. | |
70 | (false-if-exception | |
667b2508 LC |
71 | (write (apply (gexp-proc gexp) |
72 | (append (gexp-references gexp) | |
73 | (gexp-native-references gexp))) | |
74 | port)) | |
7560b00b LC |
75 | (format port " ~a>" |
76 | (number->string (object-address gexp) 16))) | |
77 | ||
78 | (set-record-type-printer! <gexp> write-gexp) | |
79 | ||
21b679f6 LC |
80 | ;; Reference to one of the derivation's outputs, for gexps used in |
81 | ;; derivations. | |
82 | (define-record-type <output-ref> | |
83 | (output-ref name) | |
84 | output-ref? | |
85 | (name output-ref-name)) | |
86 | ||
87 | (define raw-derivation | |
88 | (store-lift derivation)) | |
89 | ||
68a61e9f LC |
90 | (define* (lower-inputs inputs |
91 | #:key system target) | |
92 | "Turn any package from INPUTS into a derivation for SYSTEM; return the | |
93 | corresponding input list as a monadic value. When TARGET is true, use it as | |
94 | the cross-compilation target triplet." | |
21b679f6 LC |
95 | (with-monad %store-monad |
96 | (sequence %store-monad | |
97 | (map (match-lambda | |
98 | (((? package? package) sub-drv ...) | |
68a61e9f LC |
99 | (mlet %store-monad |
100 | ((drv (if target | |
101 | (package->cross-derivation package target | |
102 | system) | |
103 | (package->derivation package system)))) | |
21b679f6 | 104 | (return `(,drv ,@sub-drv)))) |
79c0c8cd LC |
105 | (((? origin? origin) sub-drv ...) |
106 | (mlet %store-monad ((drv (origin->derivation origin))) | |
107 | (return `(,drv ,@sub-drv)))) | |
21b679f6 LC |
108 | (input |
109 | (return input))) | |
110 | inputs)))) | |
111 | ||
b53833b2 LC |
112 | (define* (lower-reference-graphs graphs #:key system target) |
113 | "Given GRAPHS, a list of (FILE-NAME INPUT ...) lists for use as a | |
114 | #:reference-graphs argument, lower it such that each INPUT is replaced by the | |
115 | corresponding derivation." | |
116 | (match graphs | |
117 | (((file-names . inputs) ...) | |
118 | (mlet %store-monad ((inputs (lower-inputs inputs | |
119 | #:system system | |
120 | #:target target))) | |
121 | (return (map cons file-names inputs)))))) | |
122 | ||
21b679f6 LC |
123 | (define* (gexp->derivation name exp |
124 | #:key | |
68a61e9f | 125 | system (target 'current) |
21b679f6 LC |
126 | hash hash-algo recursive? |
127 | (env-vars '()) | |
128 | (modules '()) | |
129 | (guile-for-build (%guile-for-build)) | |
130 | references-graphs | |
131 | local-build?) | |
132 | "Return a derivation NAME that runs EXP (a gexp) with GUILE-FOR-BUILD (a | |
68a61e9f LC |
133 | derivation) on SYSTEM. When TARGET is true, it is used as the |
134 | cross-compilation target triplet for packages referred to by EXP. | |
21b679f6 LC |
135 | |
136 | Make MODULES available in the evaluation context of EXP; MODULES is a list of | |
137 | names of Guile modules from the current search path to be copied in the store, | |
138 | compiled, and made available in the load path during the execution of | |
139 | EXP---e.g., '((guix build utils) (guix build gnu-build-system)). | |
140 | ||
b53833b2 LC |
141 | When REFERENCES-GRAPHS is true, it must be a list of tuples of one of the |
142 | following forms: | |
143 | ||
144 | (FILE-NAME PACKAGE) | |
145 | (FILE-NAME PACKAGE OUTPUT) | |
146 | (FILE-NAME DERIVATION) | |
147 | (FILE-NAME DERIVATION OUTPUT) | |
148 | (FILE-NAME STORE-ITEM) | |
149 | ||
150 | The right-hand-side of each element of REFERENCES-GRAPHS is automatically made | |
151 | an input of the build process of EXP. In the build environment, each | |
152 | FILE-NAME contains the reference graph of the corresponding item, in a simple | |
153 | text format. | |
154 | ||
155 | In that case, the reference graph of each store path is exported in | |
156 | the build environment in the corresponding file, in a simple text format. | |
157 | ||
21b679f6 LC |
158 | The other arguments are as for 'derivation'." |
159 | (define %modules modules) | |
160 | (define outputs (gexp-outputs exp)) | |
161 | ||
b53833b2 LC |
162 | (define (graphs-file-names graphs) |
163 | ;; Return a list of (FILE-NAME . STORE-PATH) pairs made from GRAPHS. | |
164 | (map (match-lambda | |
165 | ((file-name (? derivation? drv)) | |
166 | (cons file-name (derivation->output-path drv))) | |
167 | ((file-name (? derivation? drv) sub-drv) | |
168 | (cons file-name (derivation->output-path drv sub-drv))) | |
169 | ((file-name thing) | |
170 | (cons file-name thing))) | |
171 | graphs)) | |
172 | ||
68a61e9f LC |
173 | (mlet* %store-monad (;; The following binding is here to force |
174 | ;; '%current-system' and '%current-target-system' to be | |
175 | ;; looked up at >>= time. | |
176 | (unused (return #f)) | |
177 | ||
5d098459 | 178 | (system -> (or system (%current-system))) |
68a61e9f LC |
179 | (target -> (if (eq? target 'current) |
180 | (%current-target-system) | |
181 | target)) | |
667b2508 | 182 | (normals (lower-inputs (gexp-inputs exp) |
68a61e9f LC |
183 | #:system system |
184 | #:target target)) | |
667b2508 LC |
185 | (natives (lower-inputs (gexp-native-inputs exp) |
186 | #:system system | |
187 | #:target #f)) | |
188 | (inputs -> (append normals natives)) | |
68a61e9f LC |
189 | (sexp (gexp->sexp exp |
190 | #:system system | |
191 | #:target target)) | |
21b679f6 LC |
192 | (builder (text-file (string-append name "-builder") |
193 | (object->string sexp))) | |
194 | (modules (if (pair? %modules) | |
195 | (imported-modules %modules | |
196 | #:system system | |
197 | #:guile guile-for-build) | |
198 | (return #f))) | |
199 | (compiled (if (pair? %modules) | |
200 | (compiled-modules %modules | |
201 | #:system system | |
202 | #:guile guile-for-build) | |
203 | (return #f))) | |
b53833b2 LC |
204 | (graphs (if references-graphs |
205 | (lower-reference-graphs references-graphs | |
206 | #:system system | |
207 | #:target target) | |
208 | (return #f))) | |
21b679f6 LC |
209 | (guile (if guile-for-build |
210 | (return guile-for-build) | |
53e89b17 LC |
211 | (package->derivation (default-guile) |
212 | system)))) | |
21b679f6 LC |
213 | (raw-derivation name |
214 | (string-append (derivation->output-path guile) | |
215 | "/bin/guile") | |
216 | `("--no-auto-compile" | |
217 | ,@(if (pair? %modules) | |
218 | `("-L" ,(derivation->output-path modules) | |
219 | "-C" ,(derivation->output-path compiled)) | |
220 | '()) | |
221 | ,builder) | |
222 | #:outputs outputs | |
223 | #:env-vars env-vars | |
224 | #:system system | |
225 | #:inputs `((,guile) | |
226 | (,builder) | |
227 | ,@(if modules | |
228 | `((,modules) (,compiled) ,@inputs) | |
b53833b2 LC |
229 | inputs) |
230 | ,@(match graphs | |
231 | (((_ . inputs) ...) inputs) | |
232 | (_ '()))) | |
21b679f6 | 233 | #:hash hash #:hash-algo hash-algo #:recursive? recursive? |
b53833b2 | 234 | #:references-graphs (and=> graphs graphs-file-names) |
21b679f6 LC |
235 | #:local-build? local-build?))) |
236 | ||
667b2508 LC |
237 | (define* (gexp-inputs exp #:optional (references gexp-references)) |
238 | "Return the input list for EXP, using REFERENCES to get its list of | |
239 | references." | |
21b679f6 LC |
240 | (define (add-reference-inputs ref result) |
241 | (match ref | |
242 | (((? derivation?) (? string?)) | |
243 | (cons ref result)) | |
244 | (((? package?) (? string?)) | |
245 | (cons ref result)) | |
79c0c8cd LC |
246 | (((? origin?) (? string?)) |
247 | (cons ref result)) | |
21b679f6 | 248 | ((? gexp? exp) |
667b2508 | 249 | (append (gexp-inputs exp references) result)) |
21b679f6 LC |
250 | (((? string? file)) |
251 | (if (direct-store-path? file) | |
252 | (cons ref result) | |
253 | result)) | |
254 | ((refs ...) | |
255 | (fold-right add-reference-inputs result refs)) | |
256 | (_ | |
257 | ;; Ignore references to other kinds of objects. | |
258 | result))) | |
259 | ||
260 | (fold-right add-reference-inputs | |
261 | '() | |
667b2508 LC |
262 | (references exp))) |
263 | ||
264 | (define gexp-native-inputs | |
265 | (cut gexp-inputs <> gexp-native-references)) | |
21b679f6 LC |
266 | |
267 | (define (gexp-outputs exp) | |
268 | "Return the outputs referred to by EXP as a list of strings." | |
269 | (define (add-reference-output ref result) | |
270 | (match ref | |
271 | (($ <output-ref> name) | |
272 | (cons name result)) | |
273 | ((? gexp? exp) | |
274 | (append (gexp-outputs exp) result)) | |
275 | (_ | |
276 | result))) | |
277 | ||
278 | (fold-right add-reference-output | |
279 | '() | |
280 | (gexp-references exp))) | |
281 | ||
68a61e9f LC |
282 | (define* (gexp->sexp exp #:key |
283 | (system (%current-system)) | |
284 | (target (%current-target-system))) | |
21b679f6 LC |
285 | "Return (monadically) the sexp corresponding to EXP for the given OUTPUT, |
286 | and in the current monad setting (system type, etc.)" | |
667b2508 | 287 | (define* (reference->sexp ref #:optional native?) |
21b679f6 LC |
288 | (with-monad %store-monad |
289 | (match ref | |
290 | (((? derivation? drv) (? string? output)) | |
291 | (return (derivation->output-path drv output))) | |
292 | (((? package? p) (? string? output)) | |
68a61e9f LC |
293 | (package-file p |
294 | #:output output | |
295 | #:system system | |
667b2508 | 296 | #:target (if native? #f target))) |
79c0c8cd LC |
297 | (((? origin? o) (? string? output)) |
298 | (mlet %store-monad ((drv (origin->derivation o))) | |
299 | (return (derivation->output-path drv output)))) | |
21b679f6 | 300 | (($ <output-ref> output) |
bfd9eed9 LC |
301 | ;; Output file names are not known in advance but the daemon defines |
302 | ;; an environment variable for each of them at build time, so use | |
303 | ;; that trick. | |
304 | (return `((@ (guile) getenv) ,output))) | |
21b679f6 | 305 | ((? gexp? exp) |
667b2508 LC |
306 | (gexp->sexp exp |
307 | #:system system | |
308 | #:target (if native? #f target))) | |
21b679f6 LC |
309 | (((? string? str)) |
310 | (return (if (direct-store-path? str) str ref))) | |
311 | ((refs ...) | |
667b2508 LC |
312 | (sequence %store-monad |
313 | (map (cut reference->sexp <> native?) refs))) | |
21b679f6 LC |
314 | (x |
315 | (return x))))) | |
316 | ||
317 | (mlet %store-monad | |
318 | ((args (sequence %store-monad | |
667b2508 LC |
319 | (append (map reference->sexp (gexp-references exp)) |
320 | (map (cut reference->sexp <> #t) | |
321 | (gexp-native-references exp)))))) | |
21b679f6 LC |
322 | (return (apply (gexp-proc exp) args)))) |
323 | ||
324 | (define (canonicalize-reference ref) | |
325 | "Return a canonical variant of REF, which adds any missing output part in | |
326 | package/derivation references." | |
327 | (match ref | |
328 | ((? package? p) | |
329 | `(,p "out")) | |
79c0c8cd LC |
330 | ((? origin? o) |
331 | `(,o "out")) | |
21b679f6 LC |
332 | ((? derivation? d) |
333 | `(,d "out")) | |
334 | (((? package?) (? string?)) | |
335 | ref) | |
79c0c8cd LC |
336 | (((? origin?) (? string?)) |
337 | ref) | |
21b679f6 LC |
338 | (((? derivation?) (? string?)) |
339 | ref) | |
340 | ((? string? s) | |
341 | (if (direct-store-path? s) `(,s) s)) | |
342 | ((refs ...) | |
343 | (map canonicalize-reference refs)) | |
344 | (x x))) | |
345 | ||
346 | (define (syntax-location-string s) | |
347 | "Return a string representing the source code location of S." | |
348 | (let ((props (syntax-source s))) | |
349 | (if props | |
350 | (let ((file (assoc-ref props 'filename)) | |
351 | (line (and=> (assoc-ref props 'line) 1+)) | |
352 | (column (assoc-ref props 'column))) | |
353 | (if file | |
354 | (simple-format #f "~a:~a:~a" | |
355 | file line column) | |
356 | (simple-format #f "~a:~a" line column))) | |
357 | "<unknown location>"))) | |
358 | ||
359 | (define-syntax gexp | |
360 | (lambda (s) | |
361 | (define (collect-escapes exp) | |
362 | ;; Return all the 'ungexp' present in EXP. | |
363 | (let loop ((exp exp) | |
364 | (result '())) | |
365 | (syntax-case exp (ungexp ungexp-splicing) | |
366 | ((ungexp _) | |
367 | (cons exp result)) | |
368 | ((ungexp _ _) | |
369 | (cons exp result)) | |
370 | ((ungexp-splicing _ ...) | |
371 | (cons exp result)) | |
372 | ((exp0 exp ...) | |
373 | (let ((result (loop #'exp0 result))) | |
374 | (fold loop result #'(exp ...)))) | |
375 | (_ | |
376 | result)))) | |
377 | ||
667b2508 LC |
378 | (define (collect-native-escapes exp) |
379 | ;; Return all the 'ungexp-native' forms present in EXP. | |
380 | (let loop ((exp exp) | |
381 | (result '())) | |
382 | (syntax-case exp (ungexp-native ungexp-native-splicing) | |
383 | ((ungexp-native _) | |
384 | (cons exp result)) | |
385 | ((ungexp-native _ _) | |
386 | (cons exp result)) | |
387 | ((ungexp-native-splicing _ ...) | |
388 | (cons exp result)) | |
389 | ((exp0 exp ...) | |
390 | (let ((result (loop #'exp0 result))) | |
391 | (fold loop result #'(exp ...)))) | |
392 | (_ | |
393 | result)))) | |
394 | ||
21b679f6 LC |
395 | (define (escape->ref exp) |
396 | ;; Turn 'ungexp' form EXP into a "reference". | |
667b2508 LC |
397 | (syntax-case exp (ungexp ungexp-splicing |
398 | ungexp-native ungexp-native-splicing | |
399 | output) | |
21b679f6 LC |
400 | ((ungexp output) |
401 | #'(output-ref "out")) | |
402 | ((ungexp output name) | |
403 | #'(output-ref name)) | |
404 | ((ungexp thing) | |
405 | #'thing) | |
406 | ((ungexp drv-or-pkg out) | |
407 | #'(list drv-or-pkg out)) | |
408 | ((ungexp-splicing lst) | |
667b2508 LC |
409 | #'lst) |
410 | ((ungexp-native thing) | |
411 | #'thing) | |
412 | ((ungexp-native drv-or-pkg out) | |
413 | #'(list drv-or-pkg out)) | |
414 | ((ungexp-native-splicing lst) | |
21b679f6 LC |
415 | #'lst))) |
416 | ||
667b2508 LC |
417 | (define (substitute-ungexp exp substs) |
418 | ;; Given EXP, an 'ungexp' or 'ungexp-native' form, substitute it with | |
419 | ;; the corresponding form in SUBSTS. | |
420 | (match (assoc exp substs) | |
421 | ((_ id) | |
422 | id) | |
423 | (_ | |
424 | #'(syntax-error "error: no 'ungexp' substitution" | |
425 | #'ref)))) | |
426 | ||
427 | (define (substitute-ungexp-splicing exp substs) | |
428 | (syntax-case exp () | |
429 | ((exp rest ...) | |
430 | (match (assoc #'exp substs) | |
431 | ((_ id) | |
432 | (with-syntax ((id id)) | |
433 | #`(append id | |
434 | #,(substitute-references #'(rest ...) substs)))) | |
435 | (_ | |
436 | #'(syntax-error "error: no 'ungexp-splicing' substitution" | |
437 | #'ref)))))) | |
438 | ||
21b679f6 LC |
439 | (define (substitute-references exp substs) |
440 | ;; Return a variant of EXP where all the cars of SUBSTS have been | |
441 | ;; replaced by the corresponding cdr. | |
667b2508 LC |
442 | (syntax-case exp (ungexp ungexp-native |
443 | ungexp-splicing ungexp-native-splicing) | |
21b679f6 | 444 | ((ungexp _ ...) |
667b2508 LC |
445 | (substitute-ungexp exp substs)) |
446 | ((ungexp-native _ ...) | |
447 | (substitute-ungexp exp substs)) | |
21b679f6 | 448 | (((ungexp-splicing _ ...) rest ...) |
667b2508 LC |
449 | (substitute-ungexp-splicing exp substs)) |
450 | (((ungexp-native-splicing _ ...) rest ...) | |
451 | (substitute-ungexp-splicing exp substs)) | |
21b679f6 LC |
452 | ((exp0 exp ...) |
453 | #`(cons #,(substitute-references #'exp0 substs) | |
454 | #,(substitute-references #'(exp ...) substs))) | |
455 | (x #''x))) | |
456 | ||
457 | (syntax-case s (ungexp output) | |
458 | ((_ exp) | |
667b2508 LC |
459 | (let* ((normals (delete-duplicates (collect-escapes #'exp))) |
460 | (natives (delete-duplicates (collect-native-escapes #'exp))) | |
461 | (escapes (append normals natives)) | |
21b679f6 LC |
462 | (formals (generate-temporaries escapes)) |
463 | (sexp (substitute-references #'exp (zip escapes formals))) | |
667b2508 LC |
464 | (refs (map escape->ref normals)) |
465 | (nrefs (map escape->ref natives))) | |
21b679f6 | 466 | #`(make-gexp (map canonicalize-reference (list #,@refs)) |
667b2508 | 467 | (map canonicalize-reference (list #,@nrefs)) |
21b679f6 LC |
468 | (lambda #,formals |
469 | #,sexp))))))) | |
470 | ||
471 | \f | |
472 | ;;; | |
473 | ;;; Convenience procedures. | |
474 | ;;; | |
475 | ||
53e89b17 LC |
476 | (define (default-guile) |
477 | ;; Lazily resolve 'guile-final'. This module must not refer to (gnu …) | |
478 | ;; modules directly, to avoid circular dependencies, hence this hack. | |
bdb36958 | 479 | (module-ref (resolve-interface '(gnu packages commencement)) |
53e89b17 LC |
480 | 'guile-final)) |
481 | ||
21b679f6 | 482 | (define* (gexp->script name exp |
53e89b17 | 483 | #:key (modules '()) (guile (default-guile))) |
21b679f6 LC |
484 | "Return an executable script NAME that runs EXP using GUILE with MODULES in |
485 | its search path." | |
486 | (mlet %store-monad ((modules (imported-modules modules)) | |
487 | (compiled (compiled-modules modules))) | |
488 | (gexp->derivation name | |
489 | (gexp | |
490 | (call-with-output-file (ungexp output) | |
491 | (lambda (port) | |
c17b5ab4 LC |
492 | ;; Note: that makes a long shebang. When the store |
493 | ;; is /gnu/store, that fits within the 128-byte | |
494 | ;; limit imposed by Linux, but that may go beyond | |
495 | ;; when running tests. | |
21b679f6 LC |
496 | (format port |
497 | "#!~a/bin/guile --no-auto-compile~%!#~%" | |
498 | (ungexp guile)) | |
4a4cbd0b LC |
499 | |
500 | ;; Write the 'eval-when' form so that it can be | |
501 | ;; compiled. | |
21b679f6 | 502 | (write |
4a4cbd0b LC |
503 | '(eval-when (expand load eval) |
504 | (set! %load-path | |
505 | (cons (ungexp modules) %load-path)) | |
506 | (set! %load-compiled-path | |
507 | (cons (ungexp compiled) | |
508 | %load-compiled-path))) | |
21b679f6 LC |
509 | port) |
510 | (write '(ungexp exp) port) | |
511 | (chmod port #o555))))))) | |
512 | ||
513 | (define (gexp->file name exp) | |
514 | "Return a derivation that builds a file NAME containing EXP." | |
515 | (gexp->derivation name | |
516 | (gexp | |
517 | (call-with-output-file (ungexp output) | |
518 | (lambda (port) | |
dc254e05 LC |
519 | (write '(ungexp exp) port)))) |
520 | #:local-build? #t)) | |
21b679f6 | 521 | |
21b679f6 LC |
522 | \f |
523 | ;;; | |
524 | ;;; Syntactic sugar. | |
525 | ;;; | |
526 | ||
527 | (eval-when (expand load eval) | |
667b2508 LC |
528 | (define* (read-ungexp chr port #:optional native?) |
529 | "Read an 'ungexp' or 'ungexp-splicing' form from PORT. When NATIVE? is | |
530 | true, use 'ungexp-native' and 'ungexp-native-splicing' instead." | |
21b679f6 LC |
531 | (define unquote-symbol |
532 | (match (peek-char port) | |
533 | (#\@ | |
534 | (read-char port) | |
667b2508 LC |
535 | (if native? |
536 | 'ungexp-native-splicing | |
537 | 'ungexp-splicing)) | |
21b679f6 | 538 | (_ |
667b2508 LC |
539 | (if native? |
540 | 'ungexp-native | |
541 | 'ungexp)))) | |
21b679f6 LC |
542 | |
543 | (match (read port) | |
544 | ((? symbol? symbol) | |
545 | (let ((str (symbol->string symbol))) | |
546 | (match (string-index-right str #\:) | |
547 | (#f | |
548 | `(,unquote-symbol ,symbol)) | |
549 | (colon | |
550 | (let ((name (string->symbol (substring str 0 colon))) | |
551 | (output (substring str (+ colon 1)))) | |
552 | `(,unquote-symbol ,name ,output)))))) | |
553 | (x | |
554 | `(,unquote-symbol ,x)))) | |
555 | ||
556 | (define (read-gexp chr port) | |
557 | "Read a 'gexp' form from PORT." | |
558 | `(gexp ,(read port))) | |
559 | ||
560 | ;; Extend the reader | |
561 | (read-hash-extend #\~ read-gexp) | |
667b2508 LC |
562 | (read-hash-extend #\$ read-ungexp) |
563 | (read-hash-extend #\+ (cut read-ungexp <> <> #t))) | |
21b679f6 LC |
564 | |
565 | ;;; gexp.scm ends here |