GNU bug report logs - #29926
[PATCH 1/5] gexp: Add 'eval-gexp'.

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Package: guix-patches;

Reported by: 宋文武 <iyzsong <at> member.fsf.org>

Date: Mon, 1 Jan 2018 10:34:05 UTC

Severity: normal

Tags: patch

Merged with 29925, 29927, 29928, 29929, 29930

Done: 宋文武 <iyzsong <at> outlook.com>

Bug is archived. No further changes may be made.

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Report forwarded to guix-patches <at> gnu.org:
bug#29926; Package guix-patches. (Mon, 01 Jan 2018 10:34:05 GMT) Full text and rfc822 format available.
Acknowledgement sent to 宋文武 <iyzsong <at> member.fsf.org>:
New bug report received and forwarded. Copy sent to guix-patches <at> gnu.org. (Mon, 01 Jan 2018 10:34:05 GMT) Full text and rfc822 format available.

Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: 宋文武 <iyzsong <at> member.fsf.org>
To: guix-patches <at> gnu.org
Cc: 宋文武 <iyzsong <at> member.fsf.org>
Subject: [PATCH 1/5] gexp: Add 'eval-gexp'.
Date: Mon,  1 Jan 2018 18:33:32 +0800

* guix/gexp.scm (eval-gexp): New procedure.
---
 guix/gexp.scm | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/guix/gexp.scm b/guix/gexp.scm
index f005c4d29..9709c5ecb 100644
--- a/guix/gexp.scm
+++ b/guix/gexp.scm
@@ -76,6 +76,7 @@
             gexp->derivation
             gexp->file
             gexp->script
+            eval-gexp
             text-file*
             mixed-text-file
             file-union
@@ -1167,6 +1168,21 @@ and '%load-compiled-path' to honor EXP's imported modules."
                          #:local-build? #t
                          #:substitutable? #f)))))
 
+(define* (eval-gexp exp #:optional (name "computed-value"))
+  "Return as a monadic value the EXP (a gexp) evaluate to.  This is
+implemented by building a store file NAME that contains the textual
+representation of EXP's value, and then @code{read} from it."
+  (mlet* %store-monad
+      ((drv (gexp->derivation
+             name
+             (gexp (with-output-to-file (ungexp output)
+                     (lambda ()
+                       (write (eval (quote (ungexp exp)) (current-module))))))
+             #:local-build? #t
+             #:substitutable? #f))
+       (_   (built-derivations (list drv))))
+    (return (call-with-input-file (derivation->output-path drv) read))))
+
 (define* (text-file* name #:rest text)
   "Return as a monadic value a derivation that builds a text file containing
 all of TEXT.  TEXT may list, in addition to strings, objects of any type that
-- 
2.13.3
Merged 29926. Request was from ludo <at> gnu.org (Ludovic Courtès) to control <at> debbugs.gnu.org. (Wed, 07 Mar 2018 14:05:02 GMT) Full text and rfc822 format available.
Merged 29925 29926. Request was from ludo <at> gnu.org (Ludovic Courtès) to control <at> debbugs.gnu.org. (Wed, 07 Mar 2018 14:05:03 GMT) Full text and rfc822 format available.
Merged 29925 29926 29929. Request was from ludo <at> gnu.org (Ludovic Courtès) to control <at> debbugs.gnu.org. (Wed, 07 Mar 2018 14:05:04 GMT) Full text and rfc822 format available.
Merged 29925 29926 29929 29930. Request was from ludo <at> gnu.org (Ludovic Courtès) to control <at> debbugs.gnu.org. (Wed, 07 Mar 2018 14:06:02 GMT) Full text and rfc822 format available.
Merged 29925 29926 29927 29928 29929 29930. Request was from Leo Prikler <leo.prikler <at> student.tugraz.at> to control <at> debbugs.gnu.org. (Tue, 11 May 2021 13:36:02 GMT) Full text and rfc822 format available.
Merged 29925 29926 29927 29928 29929 29930. Request was from Leo Prikler <leo.prikler <at> student.tugraz.at> to control <at> debbugs.gnu.org. (Tue, 11 May 2021 13:36:02 GMT) Full text and rfc822 format available.
bug archived. Request was from Debbugs Internal Request <help-debbugs <at> gnu.org> to internal_control <at> debbugs.gnu.org. (Wed, 09 Jun 2021 11:24:05 GMT) Full text and rfc822 format available.
This bug report was last modified 2 years and 315 days ago.

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