diff options
| -rw-r--r-- | guix/records.scm | 24 | ||||
| -rw-r--r-- | tests/records.scm | 40 |
2 files changed, 62 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 diff --git a/tests/records.scm b/tests/records.scm index d9469a78bd..45614093a0 100644 --- a/tests/records.scm +++ b/tests/records.scm @@ -170,6 +170,46 @@ (parameterize ((mark (cons 'a 'b))) (eq? (foo-bar y) (mark))))))) +(test-assert "define-record-type* & thunked & this-record" + (begin + (define-record-type* <foo> foo make-foo + foo? + (bar foo-bar) + (baz foo-baz (thunked))) + + (let ((x (foo (bar 40) + (baz (+ (foo-bar this-record) 2))))) + (and (= 40 (foo-bar x)) + (= 42 (foo-baz x)))))) + +(test-assert "define-record-type* & thunked & default & this-record" + (begin + (define-record-type* <foo> foo make-foo + foo? + (bar foo-bar) + (baz foo-baz (thunked) + (default (+ (foo-bar this-record) 2)))) + + (let ((x (foo (bar 40)))) + (and (= 40 (foo-bar x)) + (= 42 (foo-baz x)))))) + +(test-assert "define-record-type* & thunked & inherit & this-record" + (begin + (define-record-type* <foo> foo make-foo + foo? + (bar foo-bar) + (baz foo-baz (thunked) + (default (+ (foo-bar this-record) 2)))) + + (let* ((x (foo (bar 40))) + (y (foo (inherit x) (bar -2))) + (z (foo (inherit x) (baz -2)))) + (and (= -2 (foo-bar y)) + (= 0 (foo-baz y)) + (= 40 (foo-bar z)) + (= -2 (foo-baz z)))))) + (test-assert "define-record-type* & delayed" (begin (define-record-type* <foo> foo make-foo |