<div class="gmail_quote">Hi Racketeers,<div> </div><div>Just getting started in the whole Racket thing - it seems like the nicest Lisp around at this point in time. A big reason for me wanting to get to know Lisp/Scheme/Racket was to play around with macros and it seems like Racket takes the idea to its logical conclusion going beyond hygenic macros with its whole language building features. However I have to say I have found it a little difficult to fully get my head around some of the ideas (phase levels etc) so I suppose i could at least understand why some people yearn for the simplicity of "defmacro" despite its flaws. I think i just need to plow through the references some more.</div> <div> </div><div>Anyway for mostly self-educational purposes I was trying to get a particular macro working and cant seem to do it. The inspiration behind it was that I was looking at the Racket Object System and I kind of felt like there was a little less typing to get a class going. I'm also a bit of a fan of light feeling OO systems like in Python that dont really care about enforcing privacy and just wanted to give the class declaration a name and then have a public variable/property available without the need to write 3 lines. In other words instead of typing all this:</div> <div> </div><div><table cellspacing="0" style="text-align:left;white-space:inherit;font-family:serif"><tbody><tr style="white-space:inherit"><td style="padding-left:0px;padding-right:0px;vertical-align:baseline;white-space:inherit"> (<a href="http://docs.racket-lang.org/reference/createclass.html#(form._((lib._racket/private/class-internal..rkt)._class))" style="text-decoration:none;color:black" target="_blank">class</a> <a href="http://docs.racket-lang.org/reference/createclass.html#(def._((lib._racket/private/class-internal..rkt)._object~25))" style="text-decoration:none;color:blue" target="_blank">object%</a></td> </tr><tr style="white-space:inherit"><td style="padding-left:0px;padding-right:0px;vertical-align:baseline;white-space:inherit"> (<a href="http://docs.racket-lang.org/reference/createclass.html#(form._((lib._racket/private/class-internal..rkt)._init))" style="text-decoration:none;color:black" target="_blank">init</a> size) ; initialization argument</td> </tr><tr style="white-space:inherit"><td style="padding-left:0px;padding-right:0px;vertical-align:baseline;white-space:inherit"> (<a href="http://docs.racket-lang.org/reference/define.html#(form._((lib._racket/private/base..rkt)._define))" style="text-decoration:none;color:black" target="_blank">define</a> current-size size) ; field</td> </tr><tr style="white-space:inherit"><td style="padding-left:0px;padding-right:0px;vertical-align:baseline;white-space:inherit"> (<a href="http://docs.racket-lang.org/reference/createclass.html#(form._((lib._racket/private/class-internal..rkt)._define/public))" style="text-decoration:none;color:black" target="_blank">define/public</a> (get-size)</td> </tr><tr style="white-space:inherit"><td style="padding-left:0px;padding-right:0px;vertical-align:baseline;white-space:inherit"> current-size)</td> </tr><tr style="white-space:inherit"><td style="padding-left:0px;padding-right:0px;vertical-align:baseline;white-space:inherit"> ............. I wanted to be able to write something like: (init+ size) that would expand to something like: <table cellspacing="0" style="white-space:inherit;text-align:left;font-family:serif"><tbody><tr style="white-space:inherit"><td style="padding-left:0px;padding-right:0px;vertical-align:baseline;white-space:inherit"> (<a href="http://docs.racket-lang.org/reference/createclass.html#(form._((lib._racket/private/class-internal..rkt)._init))" style="text-decoration:none;color:black" target="_blank">init</a> size) ; initialization argument</td> </tr><tr style="white-space:inherit"><td style="padding-left:0px;padding-right:0px;vertical-align:baseline;white-space:inherit"> (<a href="http://docs.racket-lang.org/reference/define.html#(form._((lib._racket/private/base..rkt)._define))" style="text-decoration:none;color:black" target="_blank">define</a> size+ size) ; field</td> </tr><tr style="white-space:inherit"><td style="padding-left:0px;padding-right:0px;vertical-align:baseline;white-space:inherit"> (<a href="http://docs.racket-lang.org/reference/createclass.html#(form._((lib._racket/private/class-internal..rkt)._define/public))" style="text-decoration:none;color:black" target="_blank">define/public</a> (size++)</td> </tr><tr style="white-space:inherit"><td style="padding-left:0px;padding-right:0px;vertical-align:baseline;white-space:inherit"> size+) even better would be an expansion of (init+ size) to:</td></tr></tbody></table> <table cellspacing="0" style="white-space:inherit;text-align:left;font-family:serif"><tbody><tr style="white-space:inherit"> <td style="padding-left:0px;padding-right:0px;vertical-align:baseline;white-space:inherit"> (<a href="http://docs.racket-lang.org/reference/createclass.html#(form._((lib._racket/private/class-internal..rkt)._init))" style="text-decoration:none;color:black" target="_blank">init</a> size++) ; initialization argument</td> </tr><tr style="white-space:inherit"><td style="padding-left:0px;padding-right:0px;vertical-align:baseline;white-space:inherit"> (<a href="http://docs.racket-lang.org/reference/define.html#(form._((lib._racket/private/base..rkt)._define))" style="text-decoration:none;color:black" target="_blank">define</a> size+ size++) ; field</td> </tr><tr style="white-space:inherit"><td style="padding-left:0px;padding-right:0px;vertical-align:baseline;white-space:inherit"> (<a href="http://docs.racket-lang.org/reference/createclass.html#(form._((lib._racket/private/class-internal..rkt)._define/public))" style="text-decoration:none;color:black" target="_blank">define/public</a> (size)</td> </tr><tr style="white-space:inherit"><td style="padding-left:0px;padding-right:0px;vertical-align:baseline;white-space:inherit"> size+) so that I had a public accesssor method that had the same name as the original declaration. </td></tr></tbody></table>As mentioned this is mainly a self-educational exercise. I know there is "init-field" that would pretty much take care of this and there are some prototype based Object systems in Planet but I just wanted to see if this was possible and how/why not. Anyway hope its not too stupid a question.</td></tr></tbody></table></div> </div>