<div dir="ltr"><div>Hi Jens,<br><br>Your binding clause transformers looks very useful. I've definitely hacked together a subset of your functionality in the past so I will be using your library in the future.<br><br></div> And I can see the similar goals. We should compare notes. One question, have you tried to make your def form work with function definitions? It seems like it should be able to, by wrapping the function body with your let-syntax. Would that not work?<br> <br><div><div><div><div><div class="gmail_extra"><br><br><div class="gmail_quote">On Mon, Aug 26, 2013 at 2:14 AM, Jens Axel Søgaard <span dir="ltr"><<a href="mailto:jensaxel@soegaard.net" target="_blank">jensaxel@soegaard.net</a>></span> wrote:<br> <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Hi Stephen,<div class="im"><div><br></div><div><span style="font-family:arial,sans-serif;font-size:15.555556297302246px">> As an educational side project, I've been toying around with a</span></div> <div>> <span style="font-family:arial,sans-serif;font-size:15.555556297302246px">different way of organizing all the binding forms. What I wanted to do</span></div> <div>> <span style="font-family:arial,sans-serif;font-size:15.555556297302246px">is remove the need to manually combine current (and future) binding</span></div><div><span style="font-family:arial,sans-serif;font-size:15.555556297302246px">> f</span><span style="font-family:arial,sans-serif;font-size:15.555556297302246px">orms by moving the binding "logic" to the binding site itself.</span></div> <div><span style="font-family:arial,sans-serif;font-size:15.555556297302246px"><br></span></div></div><div><span style="font-family:arial,sans-serif;font-size:15.555556297302246px">Your goals seem similar to the ones I had for "bind".</span></div> <div><font face="arial, sans-serif" size="1">The different binding forms all have binding clauses.</font></div><div><font face="arial, sans-serif" size="1">I introduced binding clause transformers that decide what</font></div> <div><font face="arial, sans-serif" size="1">to do with a given binding clause.</font></div><div><font face="arial, sans-serif" size="1"><br></font></div><div><font face="arial, sans-serif" size="1">The binding clause transformer :delay can for example</font></div> <div><font face="arial, sans-serif" size="1">be used like this (where bind is my name for a let that understands</font></div><div><font face="arial, sans-serif" size="1">binding clause transformers).</font></div><div><span style="font-family:arial,sans-serif;font-size:15.555556297302246px"><br> </span></div><div><table style="white-space:nowrap;font-family:monospace" cellspacing="0"><tbody><tr style="white-space:inherit"><td style="padding-left:0px;padding-right:0px;vertical-align:baseline;white-space:inherit"> <span style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">(</span><span style="font-family:monospace;white-space:inherit;color:rgb(38,38,128)"><a href="http://htmlpreview.github.io/?https://github.com/soegaard/bind/blob/master/scribblings/bind.html&https://github.com/soegaard/bind/blob/master/scribblings/bind.html=false#%28form._%28%28lib._bind%2Fmain..rkt%29._bind%29%29" style="text-decoration:none;color:black" target="_blank">bind</a></span><span style="font-family:monospace"> </span><span style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">(</span><span style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">[</span><span style="font-family:monospace;white-space:inherit;color:rgb(38,38,128)">x</span><span style="font-family:monospace"> </span><span style="font-family:monospace;white-space:inherit;color:rgb(38,38,128)"><a href="http://htmlpreview.github.io/?https://github.com/soegaard/bind/blob/master/scribblings/bind.html&https://github.com/soegaard/bind/blob/master/scribblings/bind.html=false#%28form._%28%28lib._bind%2Fmain..rkt%29._~3adelay%29%29" style="text-decoration:none;color:black" target="_blank">:delay</a></span><span style="font-family:monospace"> </span><span style="font-family:monospace;white-space:inherit;color:rgb(34,139,34)">1</span><span style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">]</span></td> </tr><tr style="white-space:inherit"><td style="padding-left:0px;padding-right:0px;vertical-align:baseline;white-space:inherit"><span style="font-family:monospace"> </span><span style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">(</span><span style="font-family:monospace;white-space:inherit;color:rgb(38,38,128)"><a href="http://htmlpreview.github.io/?https://github.com/soegaard/bind/blob/master/scribblings/bind.html&https://github.com/soegaard/bind/blob/master/scribblings/bind.html=false#%28def._%28%28quote._~23~25kernel%29._%2B%29%29" style="text-decoration:none;color:blue" target="_blank">+</a></span><span style="font-family:monospace"> </span><span style="font-family:monospace;white-space:inherit;color:rgb(38,38,128)">x</span><span style="font-family:monospace"> </span><span style="font-family:monospace;white-space:inherit;color:rgb(38,38,128)">x</span><span style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">)</span><span style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">)</span><span style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">)</span></td> </tr></tbody></table></div><div><span style="font-family:arial,sans-serif;font-size:15.555556297302246px"><br></span></div><div><span style="font-family:arial,sans-serif;font-size:15.555556297302246px">At macro expansion time this is expanded into</span></div> <div><span style="font-family:arial,sans-serif;font-size:15.555556297302246px"> </span></div><table style="white-space:nowrap;font-family:monospace" cellspacing="0"><tbody><tr style="white-space:inherit"> <td style="padding-left:0px;padding-right:0px;vertical-align:baseline;white-space:inherit"><span style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">(</span><span style="font-family:monospace;white-space:inherit;color:rgb(38,38,128)"><a href="http://htmlpreview.github.io/?https://github.com/soegaard/bind/blob/master/scribblings/bind.html&https://github.com/soegaard/bind/blob/master/scribblings/bind.html=false#%28form._%28%28lib._racket%2Fprivate%2Fletstx-scheme..rkt%29._let%29%29" style="text-decoration:none;color:black" target="_blank">let</a></span><span style="font-family:monospace"> </span><span style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">(</span><span style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">[</span><span style="font-family:monospace;white-space:inherit;color:rgb(38,38,128)">x</span><span style="font-family:monospace"> </span><span style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">(</span><span style="font-family:monospace;white-space:inherit;color:rgb(38,38,128)"><a href="http://htmlpreview.github.io/?https://github.com/soegaard/bind/blob/master/scribblings/bind.html&https://github.com/soegaard/bind/blob/master/scribblings/bind.html=false#%28form._%28%28lib._racket%2Fpromise..rkt%29._delay%29%29" style="text-decoration:none;color:black" target="_blank">delay</a></span><span style="font-family:monospace"> </span><span style="font-family:monospace;white-space:inherit;color:rgb(34,139,34)">1</span><span style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">)</span><span style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">]</span><span style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">)</span></td> </tr><tr style="white-space:inherit"><td style="padding-left:0px;padding-right:0px;vertical-align:baseline;white-space:inherit"><span style="font-family:monospace"> </span><span style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">(</span><span style="font-family:monospace;white-space:inherit;color:rgb(38,38,128)"><a href="http://htmlpreview.github.io/?https://github.com/soegaard/bind/blob/master/scribblings/bind.html&https://github.com/soegaard/bind/blob/master/scribblings/bind.html=false#%28form._%28%28lib._racket%2Fprivate%2Fletstx-scheme..rkt%29._let-syntax%29%29" style="text-decoration:none;color:black" target="_blank">let-syntax</a></span><span style="font-family:monospace"> </span><span style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">(</span><span style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">[</span><span style="font-family:monospace;white-space:inherit;color:rgb(38,38,128)">clause</span><span style="font-family:monospace"> </span><span style="font-family:monospace;white-space:inherit;color:rgb(38,38,128)"><a href="http://htmlpreview.github.io/?https://github.com/soegaard/bind/blob/master/scribblings/bind.html&https://github.com/soegaard/bind/blob/master/scribblings/bind.html=false#%28form._%28%28lib._racket%2Fprivate%2Fstxcase-scheme..rkt%29._......%29%29" style="text-decoration:none;color:black" target="_blank">...</a></span><span style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">]</span><span style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">)</span></td> </tr><tr style="white-space:inherit"><td style="padding-left:0px;padding-right:0px;vertical-align:baseline;white-space:inherit"><span style="font-family:monospace"> </span><span style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">(</span><span style="font-family:monospace;white-space:inherit;color:rgb(38,38,128)"><a href="http://htmlpreview.github.io/?https://github.com/soegaard/bind/blob/master/scribblings/bind.html&https://github.com/soegaard/bind/blob/master/scribblings/bind.html=false#%28def._%28%28quote._~23~25kernel%29._%2B%29%29" style="text-decoration:none;color:blue" target="_blank">+</a></span><span style="font-family:monospace"> </span><span style="font-family:monospace;white-space:inherit;color:rgb(38,38,128)">x</span><span style="font-family:monospace"> </span><span style="font-family:monospace;white-space:inherit;color:rgb(38,38,128)">x</span><span style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">)</span><span style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">)</span><span style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">)<br> <br></span></td></tr></tbody></table><div><span style="font-family:arial,sans-serif;font-size:15.555556297302246px">where clause ... introduce a syntax binding such that x in the body</span></div><div><font face="arial, sans-serif" size="1">expands to a use of x. </font></div> <div><font face="arial, sans-serif" size="1"><br></font></div><div><font face="arial, sans-serif" size="1">This is just an example though. The key concept is the binding clause transformer.</font></div><div>Here is the documentation for bind and def (let and define):</div> <div><span style="font-family:arial,sans-serif;font-size:x-small"><a href="http://htmlpreview.github.io/?https://github.com/soegaard/bind/blob/master/scribblings/bind.html" target="_blank">http://htmlpreview.github.io/?https://github.com/soegaard/bind/blob/master/scribblings/bind.html</a></span><br> </div><div><span style="font-family:arial,sans-serif;font-size:x-small"><br></span></div><div><span style="font-family:arial,sans-serif;font-size:x-small">Here is the Github repository: </span><span style="font-family:arial,sans-serif;font-size:x-small"><a href="https://github.com/soegaard/bind" target="_blank">https://github.com/soegaard/bind</a></span></div> <div><span style="font-family:arial,sans-serif;font-size:x-small"><br></span></div><div><span style="font-family:arial,sans-serif;font-size:x-small">Another small example:</span></div><div><pre style="font-family:Consolas,'Liberation Mono',Courier,monospace;font-size:13px;margin-top:15px;margin-bottom:15px;background-color:rgb(248,248,248);border:1px solid rgb(221,221,221);line-height:19px;overflow:auto;padding:6px 10px;border-top-left-radius:3px;border-top-right-radius:3px;border-bottom-right-radius:3px;border-bottom-left-radius:3px;color:rgb(51,51,51)"> <span style="color:rgb(0,128,128)">Example:</span> <span style="color:rgb(0,128,128)">></span> <span>(</span><span style="color:rgb(153,0,0);font-weight:bold">bind</span> <span>([</span><span style="color:rgb(153,0,0);font-weight:bold">v</span> <span style="color:rgb(0,128,128)">:vector</span> <span>(</span><span style="color:rgb(153,0,0);font-weight:bold">for/vector</span> <span>([</span><span style="color:rgb(153,0,0);font-weight:bold">i</span> <span style="color:rgb(0,153,153)">5</span><span>])</span> <span>(</span><span style="color:rgb(0,134,179)">random </span><span style="color:rgb(0,153,153)">10</span><span>))])</span> <span>(</span><span style="color:rgb(0,134,179)">displayln </span><span>(</span><span style="color:rgb(153,0,0);font-weight:bold">~a</span> <span style="color:rgb(221,17,68)">"The vector "</span> <span style="color:rgb(0,128,128)">v</span> <span style="color:rgb(221,17,68)">" contains "</span> <span style="color:rgb(0,128,128)">v</span><span>))</span> <span>(</span><span style="color:rgb(0,134,179)">displayln </span><span>(</span><span style="color:rgb(153,0,0);font-weight:bold">~a</span> <span style="color:rgb(221,17,68)">"The first element is: "</span> <span>(</span><span style="color:rgb(153,0,0);font-weight:bold">v</span> <span style="color:rgb(0,153,153)">0</span><span>)))</span> <span>(</span><span style="color:rgb(153,0,0);font-weight:bold">v!</span> <span style="color:rgb(0,153,153)">0</span> <span style="color:rgb(0,153,153)">42</span><span>)</span> <span>(</span><span style="color:rgb(0,134,179)">displayln </span><span>(</span><span style="color:rgb(153,0,0);font-weight:bold">~a</span> <span style="color:rgb(221,17,68)">"The first element is now: "</span> <span>(</span><span style="color:rgb(153,0,0);font-weight:bold">v</span> <span style="color:rgb(0,153,153)">0</span><span>)))</span> <span>(</span><span style="color:rgb(0,134,179)">displayln </span><span>(</span><span style="color:rgb(153,0,0);font-weight:bold">~a</span> <span style="color:rgb(221,17,68)">"The middle three elements are: "</span> <span>(</span><span style="color:rgb(153,0,0);font-weight:bold">v</span> <span style="color:rgb(0,153,153)">1</span> <span style="color:rgb(0,153,153)">4</span><span>))))</span></pre> </div><div><font face="arial, sans-serif" size="1"><br></font></div><div><font face="arial, sans-serif" size="1">This expands into uses of vector-ref and vector-set! so there is no runtime penalty</font></div><div><font face="arial, sans-serif" size="1">for using this shorthand.</font></div> <div><font face="arial, sans-serif" size="1"><br></font></div><div><font face="arial, sans-serif" size="1">/Jens Axel</font></div><div><font face="arial, sans-serif" size="1"><br></font></div><div><br></div><div class="gmail_extra"> <div class="gmail_quote">2013/8/26 Stephen Chang <span dir="ltr"><<a href="mailto:stchang@ccs.neu.edu" target="_blank">stchang@ccs.neu.edu</a>></span><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> <div><div class="h5"> Hi dev,<br> <br> I've noticed that Racket has a lot of convenient binding forms but<br> they don't fit together unless someone does it manually (for example<br> there's match-let and match-let-values, but no match-for).<br> <br> As an educational side project, I've been toying around with a<br> different way of organizing all the binding forms. What I wanted to do<br> is remove the need to manually combine current (and future) binding<br> forms by moving the binding "logic" to the binding site itself.<br> <br> Inspired by the in-vogue generics movement in the Racket world, I've<br> hacked together a sort of "generic interface" for bindings (in<br> reality, it's just a bunch of syntax properties right now), and<br> implemented alternate versions of some of the main binding forms that<br> support "instances" of these generic bindings.<br> <br> To illustrate, here are some test cases for a generic define I<br> implemented (~define). I also implemented binding "instances" for<br> match and values (which I arbitrarily named $ and ~v below) and I can<br> use these forms in (mostly) any binding position that supports generic<br> bindings.<br> <br> ;; functions<br> > (~define (f1 x y) (+ x y))<br> > (f1 10 20)<br> 30<br> > (~define (f2 ($ (list x y))) (+ x y))<br> > (f2 (list 10 20))<br> 30<br> <br> ;; non-functions<br> > (~define a1 100)<br> > a1<br> 100<br> > (~define (~v a2 a3) (values 134 456))<br> > a2<br> 134<br> > a3<br> 456<br> <br> You can nest bind instances too:<br> <br> > (~define (~v ($ (list b1 b2)) b3) (values (list 22 33) 44))<br> > b1<br> 22<br> > b2<br> 33<br> > b3<br> 44<br> <br> Does anyone think this is useful? Or is it just a lot of work to save<br> a little bit of typing? Has anyone tried something like this before?<br> <br> It's still very much a work in progress but I figure I would ask for<br> some feedback earlier rather than too later, in case there is<br> something that makes this infeasible.<br> <br> Brave souls can look at the hackery here:<br> <a href="https://github.com/stchang/generic-bind/blob/master/generic-bind.rkt" target="_blank">https://github.com/stchang/generic-bind/blob/master/generic-bind.rkt</a><br> (Warning: I'm still trying to figure out all the toys in the Racket<br> macro toolbox. For the most part, everything still looks like a<br> syntax-rule/case/parse/->datum nail to my hammer.)<br> <br> Technical question: I couldn't figure out a nice way to implement<br> ~let. Essentially, I want a let form where some clauses are let-values<br> and some are match-let, but I need to bind them all at the same time,<br> like let. I can't define a ~lambda that works with values because<br> functions in racket can't receive values. Anyone have any ideas?<br> <br> Side observation: Trying to get things to work with multiple return<br> values was a pain because they don't compose (as in, functions can<br> produce them but can't receive them). Not sure if anything can be done<br> about this though.<br></div></div> _________________________<br> Racket Developers list:<br> <a href="http://lists.racket-lang.org/dev" target="_blank">http://lists.racket-lang.org/dev</a><span class="HOEnZb"><font color="#888888"><br> </font></span></blockquote></div><span class="HOEnZb"><font color="#888888"><br><br clear="all"><div><br></div>-- <br>-- <br>Jens Axel Søgaard<br><br> </font></span></div></div> </blockquote></div><br></div></div></div></div></div></div>