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| author | nee <nee.git@cock.li> | 2017-10-25 20:44:54 +0200 |
|---|---|---|
| committer | Ludovic Courtès <ludo@gnu.org> | 2017-11-05 15:21:53 +0100 |
| commit | 6692d8454a89e542d85d2b6a93adfd373aeec39c (patch) | |
| tree | 1ab3e46a2dccf04a2d7c1b9ddc0893061ff7553b | |
| parent | 50c229caf9b8d09944838f0fb92d3121bbb2a4bc (diff) | |
| download | guix-6692d8454a89e542d85d2b6a93adfd373aeec39c.tar.gz | |
guix: records: Add match-record.
* guix/records.scm: New syntax-rule. Signed-off-by: Ludovic Courtès <ludo@gnu.org>
| -rw-r--r-- | guix/records.scm | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/guix/records.scm b/guix/records.scm index 7de5fccef6..1f00e16603 100644 --- a/guix/records.scm +++ b/guix/records.scm @@ -26,7 +26,8 @@ #:export (define-record-type* alist->record object->fields - recutils->alist)) + recutils->alist + match-record)) ;;; Commentary: ;;; @@ -375,4 +376,19 @@ pairs. Stop upon an empty line (after consuming it) or EOF." (else (error "unmatched line" line)))))))) +(define-syntax match-record + (syntax-rules () + "Bind each FIELD of a RECORD of the given TYPE to it's FIELD name. +The current implementation does not support thunked and delayed fields." + ((_ record type (field fields ...) body ...) + (if (eq? (struct-vtable record) type) + ;; TODO compute indices and report wrong-field-name errors at + ;; expansion time + ;; TODO support thunked and delayed fields + (let ((field ((record-accessor type 'field) record))) + (match-record record type (fields ...) body ...)) + (throw 'wrong-type-arg record))) + ((_ record type () body ...) + (begin body ...)))) + ;;; records.scm ends here |