<div>Hi,</div><div><br></div><div>I'm pleased to announce a new version of Magritte - Magritte 3. The rational for Magritte 3 is eloquently described by Lukas in his mail below.</div><div>The work on Magritte 3 was started by Esteban and completed by myself.</div>
<div><br></div><div>I've created a screen-cast which describes:</div><div><ul><li> the rational for Magritte 3</li><li> the refactorings available to ease the transition from Magritte 1 or 2 to Magritte 3</li><li> A walk-through of updating a sample from Magritte 2 to Magritte 3.</li>
</ul></div><div>The screen-cast is on vimeo at:</div><div><a href="http://vimeo.com/37032840">http://vimeo.com/37032840</a></div><div><br></div><div>The sample used in screen-cast can be downloaded as:</div><div><br></div>
<div><blockquote class="gmail_quote" style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">Gofer it<br>
<span class="Apple-tab-span" style="white-space:pre"> </span>url: '<a href="http://ss3.gemstone.com/ss/MagritteMagic">http://ss3.gemstone.com/ss/MagritteMagic</a>';<br><span class="Apple-tab-span" style="white-space:pre"> </span>package: 'ConfigurationOfMagritteMagic';<br>
<span class="Apple-tab-span" style="white-space:pre"> </span>load.<br><span class="Apple-tab-span" style="white-space:pre"> <br></span>(Smalltalk at: #ConfigurationOfMagritteMagic) load.</blockquote></div><div><br></div>
<div>The slides used in the screen-case can be viewed on slideshare at:</div><div><br></div><a href="http://www.slideshare.net/nickager/magritte3">http://www.slideshare.net/nickager/magritte3</a><div><br></div><div>Enjoy</div>
<div><br></div><div>Nick</div><div><br></div><div><br></div><div><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">---------- Forwarded message ----------</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">From:</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"> </span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><b class="gmail_sendername">Lukas Renggli</b></span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"> </span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><span dir="ltr"><<a href="mailto:renggli@gmail.com" target="_blank" style="color:rgb(17,85,204)">renggli@gmail.com</a>></span></span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">Date: 17 November 2010 17:21</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">Subject: Re: Providing lookup environment for descriptions</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">To: "Magritte, Pier and Related Tools ..." <</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><a href="mailto:smallwiki@iam.unibe.ch" target="_blank" style="color:rgb(17,85,204)">smallwiki@iam.unibe.ch</a></span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">></span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br></span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">The way Magritte builds descriptions by default has become quite a</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">nuisance. </span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">I think that at some point Magritte should be improved</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">in that regard. I wrote a proposal this summer for how to proceed</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">, </span></div>
<div><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">but of course I had to finish my writing and never actually</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">found the time to implement it:</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br></span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">--------------------</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br></span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">I propose to perform the following (non-backward compatible) changes</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">in the Magritte 2 code-base to resolve some major annoyances and</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">issues that keep on reoccurring:</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br></span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">- Move descriptions from class-side to instance-side. This resolves</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">various issues such as cache-invalidation, instance specific</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">descriptions, dynamic descriptions, context dependent descriptions,</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">etc. Furthermore the descriptions will be closer to the code they</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">describe and it will be possible to describe class- and instance-side</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">of an object, not just the instance-side.</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br></span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">- Rename the method #description as the default entry point into</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">Magritte to #magritteDescription. This avoids common problems where</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">the domain model already defines such a method.</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br></span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">- Instead of using a naming convention for description methods, use a</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">pragma called <magritteDescription> to annotate the methods. And to extend and</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">change existing descriptions use <magritteDescription: aSelector>. Finally all</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">Smalltalk implementation reached a consensus of pragmas that can be</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">safely used cross-platform.</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br></span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">All in all the "new" Magritte would look like in the following</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">example. Imagine a shop item with the accessor #place:</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br></span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"> Item>>place</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"> ^ place</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br></span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"> Item>>place: aString</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"> place := aString</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br></span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">The meta-description is defined on the instance-side and annotated. It</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">can refer to itself for the possible places:</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br></span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"> Item>>placeDescription</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"> <magritteDescription></span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br></span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"> ^ MASingleOptionDescription new</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"> options: self possiblePlaces;</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"> label: 'Place of Item';</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"> accessor: #place;</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"> yourself</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br></span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">Class extensions can modify a description using:</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br></span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"> Item>></span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"></span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">placeDescriptionXmlStorage: aDescription</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"> <magritteDescription: #placeDescription></span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br></span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"> ^ placeDescription xmlTag: 'xname'</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br></span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">Since these changes are not backward compatible I'll try to provide</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">automatic refactorings for most parts. Moving existing code to the new</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">codebase will certainly cause some problems, but in the long run I</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">believe this to be a much better approach than the current one. If</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">people have any feedback, concerns or other changes that would be</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">important in the same run I am happy to hear them.</span><span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px"><br>
</span></div>