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author | Marius Bakke <mbakke@fastmail.com> | 2019-10-08 19:24:34 +0200 |
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committer | Marius Bakke <mbakke@fastmail.com> | 2019-10-08 19:24:34 +0200 |
commit | d1f3b333e6176a7879ab3742bbebb2a99f61a528 (patch) | |
tree | 8bd82ce68bd2534a48bf13c7256997f82dd1b3f4 /guix/json.scm | |
parent | e01d384efcdaf564bbb221e43b81e087c8e2af06 (diff) | |
parent | 861907f01efb1cae7f260e8cb7b991d5034a486a (diff) | |
download | guix-patches-d1f3b333e6176a7879ab3742bbebb2a99f61a528.tar guix-patches-d1f3b333e6176a7879ab3742bbebb2a99f61a528.tar.gz |
Merge branch 'master' into staging
Diffstat (limited to 'guix/json.scm')
-rw-r--r-- | guix/json.scm | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/guix/json.scm b/guix/json.scm new file mode 100644 index 0000000000..20f0bd8f13 --- /dev/null +++ b/guix/json.scm @@ -0,0 +1,62 @@ +;;; GNU Guix --- Functional package management for GNU +;;; Copyright © 2018, 2019 Ludovic Courtès <ludo@gnu.org> +;;; +;;; 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 (guix json) + #:use-module (json) + #:use-module (srfi srfi-9) + #:export (define-json-mapping)) + +;;; Commentary: +;;; +;;; Helpers to map JSON objects to SRFI-9 records. Taken from (guix swh). +;;; +;;; Code: + +(define-syntax-rule (define-json-reader json->record ctor spec ...) + "Define JSON->RECORD as a procedure that converts a JSON representation, +read from a port, string, or hash table, into a record created by CTOR and +following SPEC, a series of field specifications." + (define (json->record input) + (let ((table (cond ((port? input) + (json->scm input)) + ((string? input) + (json-string->scm input)) + ((or (null? input) (pair? input)) + input)))) + (let-syntax ((extract-field (syntax-rules () + ((_ table (field key json->value)) + (json->value (assoc-ref table key))) + ((_ table (field key)) + (assoc-ref table key)) + ((_ table (field)) + (assoc-ref table + (symbol->string 'field)))))) + (ctor (extract-field table spec) ...))))) + +(define-syntax-rule (define-json-mapping rtd ctor pred json->record + (field getter spec ...) ...) + "Define RTD as a record type with the given FIELDs and GETTERs, à la SRFI-9, +and define JSON->RECORD as a conversion from JSON to a record of this type." + (begin + (define-record-type rtd + (ctor field ...) + pred + (field getter) ...) + + (define-json-reader json->record ctor + (field spec ...) ...))) |