diff options
Diffstat (limited to 'guix/records.scm')
| -rw-r--r-- | guix/records.scm | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/guix/records.scm b/guix/records.scm index 816e9f6f01..b68aaae1c4 100644 --- a/guix/records.scm +++ b/guix/records.scm @@ -51,6 +51,7 @@ fields, and DELAYED is the list of identifiers of delayed fields." ((_ type name ctor (expected ...) #:thunked thunked #:delayed delayed + #:innate innate #:defaults defaults) (define-syntax name (lambda (s) @@ -73,8 +74,11 @@ fields, and DELAYED is the list of identifiers of delayed fields." #`(make-struct type 0 #,@(map (lambda (field index) (or (field-inherited-value field) - #`(struct-ref #,orig-record - #,index))) + (if (innate-field? field) + (wrap-field-value + field (field-default-value field)) + #`(struct-ref #,orig-record + #,index)))) '(expected ...) (iota (length '(expected ...)))))) @@ -84,6 +88,9 @@ fields, and DELAYED is the list of identifiers of delayed fields." (define (delayed-field? f) (memq (syntax->datum f) 'delayed)) + (define (innate-field? f) + (memq (syntax->datum f) 'innate)) + (define (wrap-field-value f value) (cond ((thunked-field? f) #`(lambda () #,value)) @@ -164,7 +171,8 @@ may look like this: thing? (name thing-name (default \"chbouib\")) (port thing-port - (default (current-output-port)) (thunked))) + (default (current-output-port)) (thunked)) + (loc thing-location (innate) (default (current-source-location)))) This example defines a macro 'thing' that can be used to instantiate records of this type: @@ -190,7 +198,8 @@ It is possible to copy an object 'x' created with 'thing' like this: (thing (inherit x) (name \"bar\")) This expression returns a new object equal to 'x' except for its 'name' -field." +field and its 'loc' field---the latter is marked as \"innate\", so it is not +inherited." (define (field-default-value s) (syntax-case s (default) @@ -202,6 +211,7 @@ field." (define-field-property-predicate delayed-field? delayed) (define-field-property-predicate thunked-field? thunked) + (define-field-property-predicate innate-field? innate) (define (wrapped-field? s) (or (thunked-field? s) (delayed-field? s))) @@ -251,6 +261,7 @@ field." (let* ((field-spec #'((field get properties ...) ...)) (thunked (filter-map thunked-field? field-spec)) (delayed (filter-map delayed-field? field-spec)) + (innate (filter-map innate-field? field-spec)) (defaults (filter-map field-default-value #'((field properties ...) ...)))) (with-syntax (((field-spec* ...) @@ -278,6 +289,7 @@ field." (field ...) #:thunked #,thunked #:delayed #,delayed + #:innate #,innate #:defaults #,defaults)))))))) (define* (alist->record alist make keys |