<HTML><BODY>Thank you. This works just fine in any place, where function is expected. But the case with "case" still doesn't work (case 5     [((hash-dot (+ 2 3))) 1]     [else 2]) => 2 I think, that I need to do something with the Racket reader. Понедельник, 29 июля 2013, 13:53 -04:00 от Vincent St-Amour <stamourv@ccs.neu.edu>: <BLOCKQUOTE class=mailru-blockquote style="PADDING-BOTTOM: 0px; PADDING-TOP: 0px; PADDING-LEFT: 10px; MARGIN: 10px; BORDER-LEFT: #0857a6 1px solid; PADDING-RIGHT: 0px"> <DIV> <DIV class="js-helper js-readmsg-msg"> <STYLE type=text/css></STYLE> <DIV class=mr_read__body id=style_13751204460000000879><BASE href="https://e.mail.ru/" target=_self> <DIV id=style_13751204460000000879_BODY>Here's a quick solution:     #lang racket     (define-syntax-rule (hash-dot e)       (let-syntax ([computed-e (lambda (stx) (datum->syntax #'e e))])         (computed-e)))     (hash-dot (+ 2 3)) This defines a local macro that computes the value of `e' at compile time. Any binding that you use in `e' will need to be bound at syntax time (which, in #lang racket, is all of racket/base), which may mean using `(require (for-syntax X))'. If you try to compute, say, a function at compile-time, you'll run into trouble, though. Vincent At Mon, 29 Jul 2013 06:25:21 +0400, Roman Klochkov wrote: > > [1 <multipart/alternative (7bit)>] > [1.1 <text/plain; utf-8 (base64)>] > Is there simple way to calculate during compilation. Something like #. in Common Lisp. > > For example how to do something like > (case ftype > ((#.(keyword->g-type 'enum) > #.(keyword->g-type 'flags)) > (convert-to-foreign value (g-type->lisp type))) > (#.(keyword->g-type 'double) > (coerce value 'double-float)) > (#.(keyword->g-type 'float) > (coerce value 'single-float)) > ((#.(keyword->g-type 'int) > #.(keyword->g-type 'uint) > #.(keyword->g-type 'long) > #.(keyword->g-type 'ulong) > #.(keyword->g-type 'int64) > #.(keyword->g-type 'uint64)) > (round value)) > (else value)) > > > > where keyword->g-type is a function (-> symbol? exact-integer?). > > I don't want to place resulting numbers, because then there will be a lot of "magic numbers" corresponfing to different foreign types. > > > -- > Roman Klochkov > [1.2 <text/html; utf-8 (base64)>] > > [2 <text/plain; us-ascii (7bit)>] > ____________________ > Racket Users list: > <A href="http://lists.racket-lang.org/users" target=_blank>http://lists.racket-lang.org/users</A> </DIV><BASE href="https://e.mail.ru/" target=_self></DIV></DIV></DIV></BLOCKQUOTE> -- Roman Klochkov </BODY></HTML>