diff options
Diffstat (limited to 'guix/records.scm')
| -rw-r--r-- | guix/records.scm | 24 |
1 files changed, 22 insertions, 2 deletions
diff --git a/guix/records.scm b/guix/records.scm index 0649c90ea3..244b124098 100644 --- a/guix/records.scm +++ b/guix/records.scm @@ -25,6 +25,8 @@ #:use-module (ice-9 regex) #:use-module (ice-9 rdelim) #:export (define-record-type* + this-record + alist->record object->fields recutils->alist @@ -93,6 +95,17 @@ interface\" (ABI) for TYPE is equal to COOKIE." (() #t))))))) +(define-syntax-parameter this-record + (lambda (s) + "Return the record being defined. This macro may only be used in the +context of the definition of a thunked field." + (syntax-case s () + (id + (identifier? #'id) + (syntax-violation 'this-record + "cannot be used outside of a record instantiation" + #'id))))) + (define-syntax make-syntactic-constructor (syntax-rules () "Make the syntactic constructor NAME for TYPE, that calls CTOR, and @@ -148,7 +161,14 @@ of TYPE matches the expansion-time ABI." (define (wrap-field-value f value) (cond ((thunked-field? f) - #`(lambda () #,value)) + #`(lambda (x) + (syntax-parameterize ((this-record + (lambda (s) + (syntax-case s () + (id + (identifier? #'id) + #'x))))) + #,value))) ((delayed-field? f) #`(delay #,value)) (else value))) @@ -308,7 +328,7 @@ inherited." (with-syntax ((real-get (wrapped-field-accessor-name field))) #'(define-inlinable (get x) ;; The real value of that field is a thunk, so call it. - ((real-get x))))))) + ((real-get x) x)))))) (define (delayed-field-accessor-definition field) ;; Return the real accessor for FIELD, which is assumed to be a |