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| author | Ludovic Courtès <ludo@gnu.org> | 2015-06-11 22:22:05 +0200 |
|---|---|---|
| committer | Ludovic Courtès <ludo@gnu.org> | 2015-06-11 23:33:32 +0200 |
| commit | faef3b6a96114524c2a25e3b84caa042a2d2e598 (patch) | |
| tree | cbff33bc1d9bc350177b6c75e6b9687ed99a655d | |
| parent | b9c8647337762983ac046aec66328ad0efd2f276 (diff) | |
| download | gnu-guix-faef3b6a96114524c2a25e3b84caa042a2d2e598.tar gnu-guix-faef3b6a96114524c2a25e3b84caa042a2d2e598.tar.gz | |
records: Factorize field property predicates.
* guix/records.scm (define-field-property-predicate): New macro.
(define-record-type*)[thunked-field?, delayed-field?]: Use it.
| -rw-r--r-- | guix/records.scm | 30 |
1 files changed, 13 insertions, 17 deletions
diff --git a/guix/records.scm b/guix/records.scm index f66fda8a32..dbdd2201a6 100644 --- a/guix/records.scm +++ b/guix/records.scm @@ -142,6 +142,17 @@ fields, and DELAYED is the list of identifiers of delayed fields." '(expected ...) fields))))))))))))) +(define-syntax-rule (define-field-property-predicate predicate property) + "Define PREDICATE as a procedure that takes a syntax object and, when passed +a field specification, returns the field name if it has the given PROPERTY." + (define (predicate s) + (syntax-case s (property) + ((field (property values (... ...)) _ (... ...)) + #'field) + ((field _ properties (... ...)) + (predicate #'(field properties (... ...)))) + (_ #f)))) + (define-syntax define-record-type* (lambda (s) "Define the given record type such that an additional \"syntactic @@ -189,23 +200,8 @@ field." (field-default-value #'(field options ...))) (_ #f))) - (define (delayed-field? s) - ;; Return the field name if the field defined by S is delayed. - (syntax-case s (delayed) - ((field (delayed) _ ...) - #'field) - ((field _ options ...) - (delayed-field? #'(field options ...))) - (_ #f))) - - (define (thunked-field? s) - ;; Return the field name if the field defined by S is thunked. - (syntax-case s (thunked) - ((field (thunked) _ ...) - #'field) - ((field _ options ...) - (thunked-field? #'(field options ...))) - (_ #f))) + (define-field-property-predicate delayed-field? delayed) + (define-field-property-predicate thunked-field? thunked) (define (wrapped-field? s) (or (thunked-field? s) (delayed-field? s))) |