On Thu, 2009-12-24 at 05:31 -0600, Eduardo Cavazos wrote:
> > Something I use heavily in the 'box2d-lite' code is a
> > 'define-record-type++' macro:
> >
> > http://github.com/dharmatech/box2d-lite/blob/master/util/define-record-type.sls
> >
> > It expands into a call to the full 'define-record-type' along with some
> > additional definitions.
> >
> > However, it's cheesy in that it only supports a subset of the syntax of
> > the full 'define-record-type', along with some additional syntax.
> >
> > Is there a pure R6RS definition of the 'define-record-type' macro
> > available somewhere? The definitions I found had implementation specific
> > code in them.
> >
> > I'd rather base my 'define-record-type' deriviative on a full version.
> > I.e. start with the full definition and throw in my extensions.
On Thu, 2009-12-24 at 15:37 -0800, Derick Eddington wrote:
> You don't need to go that far. Just extract what you need and pass
> everything else through:
>
> (define-syntax define-record-type++
> (lambda (stx)
> (syntax-case stx ()
> ((_ name-spec is-type import-type rest ...)
> ;; Invalid name-spec will be detected by define-record-type.
> ;; Invalid is-type or import-type should be detected by
> ;; define-is-type-syntax or define-import-type-syntax.
> ;; Invalid rest will be detected by define-record-type.
> (let loop ((r (syntax (rest ...)))
> (f #F)
> (m #F)
> (a (quote ())))
> (if (null? r)
> (if (and f m)
> (with-syntax (((field-name ...) f)
> (methods m)
> ((DRT-clauses ...) (reverse a))
> (type-name (syntax-case (syntax name-spec) ()
> ((x . _) (syntax x))
> (_ (syntax name-spec)))))
> (syntax
> (begin
> (define-record-type name-spec
> DRT-clauses ...)
> (define-is-type-syntax is-type
> type-name
> (fields field-name ...)
> methods)
> (define-import-type-syntax import-type
> type-name
> (fields field-name ...)
> methods))))
> (syntax-violation #F "missing fields and/or methods" stx #F))
> (syntax-case (car r) (fields methods)
> ((fields x ...)
> ;; Multiple fields clauses will be detected by
> define-record-type.
> (loop (cdr r)
> (map (lambda (x)
> (syntax-case x ()
> ((_ name . _) (syntax name))
> (_ x)))
> (syntax (x ...)))
> m
> (cons (car r) a)))
> ((methods . _)
> ;; Invalid methods sub-clauses should be detected by
> ;; define-is-type-syntax and/or define-import-type-syntax.
> (if m
> (syntax-violation #F "multiple methods clauses" stx #F)
> (loop (cdr r) f (car r) a)))
> (_
> (loop (cdr r) f m (cons (car r) a))))))))))
>
>
> I tested that this works:
>
> (define-record-type++ (foo foo-maker is-it-a-foo?)
> is-foo import-foo
> (fields a (mutable b) (immutable c c-get))
> (methods)
> (sealed #T))
I added a library '(dharmalab records define-record-type)' to dharmalab:
http://github.com/dharmatech/dharmalab
which provides 'define-record-type++'.
I changed 'define-record-type++' so that you don't have to explicitly
name the is-type and import-type macros.
A couple of examples are at:
http://github.com/dharmatech/dharmalab/blob/master/records/define-record-type.org
Ed
