thanks, if just replaced the 'begin by 'let () to allow internal definitions but i haven't test it yet (finally no need in my code of define internal at this point) regards, Damien
On Mon, Sep 12, 2022 at 10:47 AM Taylan Kammer <taylan.kam...@gmail.com> wrote: > On 12.09.2022 09:42, Damien Mattei wrote: > > > > Hello, > > i can not find in the scheme community a definition of 'case in term of > macro as for when, unless,while,do... does anyone have it? > > thanks, > > Damien > > The RnRS often contain such definitions. The following is taken from > R7RS-small: > > (define-syntax case > (syntax-rules (else =>) > ((case (key ...) clauses ...) > (let ((atom-key (key ...))) > (case atom-key clauses ...))) > ((case key (else => result)) > (result key)) > ((case key > (else result1 result2 ...)) > (begin result1 result2 ...)) > ((case key > ((atoms ...) result1 result2 ...)) > (if (memv key ’(atoms ...)) > (begin result1 result2 ...))) > ((case key > ((atoms ...) => result)) > (if (memv key ’(atoms ...)) > (result key))) > ((case key > ((atoms ...) => result) > clause clauses ...) > (if (memv key ’(atoms ...)) > (result key) > (case key clause clauses ...))) > ((case key > ((atoms ...) result1 result2 ...) > clause clauses ...) > (if (memv key ’(atoms ...)) > (begin result1 result2 ...) > (case key clause clauses ...)))) > > -- > Taylan > >
