diff options
Diffstat (limited to 'guix/json.scm')
| -rw-r--r-- | guix/json.scm | 31 |
1 files changed, 26 insertions, 5 deletions
diff --git a/guix/json.scm b/guix/json.scm index 20f0bd8f13..3e3a28b749 100644 --- a/guix/json.scm +++ b/guix/json.scm @@ -1,5 +1,5 @@ ;;; GNU Guix --- Functional package management for GNU -;;; Copyright © 2018, 2019 Ludovic Courtès <ludo@gnu.org> +;;; Copyright © 2018, 2019, 2020 Ludovic Courtès <ludo@gnu.org> ;;; ;;; This file is part of GNU Guix. ;;; @@ -18,15 +18,33 @@ (define-module (guix json) #:use-module (json) - #:use-module (srfi srfi-9) - #:export (define-json-mapping)) + #:use-module (srfi srfi-9)) ;;; Commentary: ;;; ;;; Helpers to map JSON objects to SRFI-9 records. Taken from (guix swh). +;;; This module is superseded by 'define-json-mapping' as found since version +;;; 4.2.0 of Guile-JSON and will be removed once migration is complete. ;;; ;;; Code: +(define-syntax define-as-needed + (lambda (s) + "Define the given syntax rule unless (json) already provides it." + (syntax-case s () + ((_ (macro args ...) body ...) + (if (module-defined? (resolve-interface '(json)) + (syntax->datum #'macro)) + #'(eval-when (expand load eval) + ;; Re-export MACRO from (json). + (module-re-export! (current-module) '(macro))) + #'(begin + ;; Using Guile-JSON < 4.2.0, so provide our own MACRO. + (define-syntax-rule (macro args ...) + body ...) + (eval-when (expand load eval) + (module-export! (current-module) '(macro))))))))) + (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 @@ -48,8 +66,11 @@ following SPEC, a series of field specifications." (symbol->string 'field)))))) (ctor (extract-field table spec) ...))))) -(define-syntax-rule (define-json-mapping rtd ctor pred json->record - (field getter spec ...) ...) +;; For some reason we cannot just have colliding definitions of +;; 'define-json-mapping' (that leads to a build failure in users of this +;; module), hence the use of 'define-as-needed'. +(define-as-needed (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 |