<div class="gmail_quote">On Mon, Jul 6, 2009 at 7:03 AM, Ralph Johnson <span dir="ltr"><<a href="mailto:johnson@cs.uiuc.edu">johnson@cs.uiuc.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div class="im"> But I think that the forces opposing</div>
minimalism are probably complex and powerful. If we don't understand<br>
them, we are unlikely to defeat them.</blockquote><div><br></div><div>The force that opposes minimalism is actually just mental inertia. It is easier to not think about what you're doing, and fling code at a problem until you find a solution. To actually consider how the semantics of the method and object names you choose will affect future developers is simply beyond the capacity of most programmers, who tend to get hung up on the details of implementation. And when they do, the remainder of the complexity that creeps into Squeak images is a product of "taste".</div>
<div><br></div><div>Look at how many methods are in core classes that there because of some weird corner case where the semantics did not quite work. Objects veryDeepCopy* tend to fall into this category. Then you get the pure semantic sugar methods, which can be found in methods such as the SyntaxMorph's polution of object with the 5 selfWrittenAs* methods. </div>
</div><div><br></div>Then there is the huge number of methods that are in desperate need of some thought and refactoring. Consider:<div><br></div><div>anObject actionMap </div><div><br></div><div>vs</div><div><br></div><div>
EventManager actionMapFor: anObject </div><div><br></div><div>vs</div><div><br></div><div>EventManager actionMaps at: anObject ifAbsent: [ EventMangager createActionMap ]</div><div><br></div><div>And then consider what the Morph class does in comparison.</div>
<div><br></div><div>aMorph extension valueOfProperty: #actionMap.</div><div><br></div><div>vs</div><div><br></div><div>aMorph extension otherProperties at: aSymbol ifAbsent: [^ aBlock value]</div><div><br></div><div>where extension is a MorphExtension object, and otherProperties is an IdentityDictionary.</div>
<div><br></div><div>If you look at what is actually trying to be done, both cases are attempting to provide ad hoc properties to a base object. On the one hand, a global external weak reference dictionary was used to do the mapping, and on the other a per-instance dictionary was created to amend the object's properties. They do the same thing (return a dictionary) with roughly the same semantics, but this is definitely a simpler way than having two hyperbolically parallel implementations.</div>
<div><br></div><div>What really needs to happen at some point is a "Grand-Refactoring" where in some fundamental architectural changes can be made with a view towards simplifying the end-user semantics. Look at all the places someone has hacked a new method in a core class, that is only used in a specific context or work around, and then identify the features and generalized semantics that would have accounted for what became a fringe case. One feature that would fix many of these issues is to just provide one standard way for instances of Object to add ad hoc properties and methods. Another feature that has yet to be used properly is traits. Packages are a third.</div>
<div><br></div><div>Why a Grand-Refactoring might never happen, is it will require rewriting substantial amounts of the image, and will necessarily break all existing applications. You can leave in shims to port old code, but unless you remove them quickly (within a year) you ensure that habitual factors will prevent them from ever being removed. You can also do a Slightly-Less-Grand-Refactoring every couple years, to pick any weeds that have grown up between the cracks, or fix issues that people have been working around in the original one. But you don't want to pump out one of those more than once a year, to give people a stable base.</div>
<div><br></div><div>Overcoming mental inertia is very hard work. You have to change your habits, and see things you've stared at for too long with fresh eyes. But it can be done if there is enough will in the community.</div>
<div><br>-- <br>-=-=-=-=-=-=-=-=-=-=- <a href="http://blog.dloh.org/">http://blog.dloh.org/</a><br>
</div>