Structure and Interpretation of Computer Programmers

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Wednesday, December 31, 2014

Rubbies and sores

I imagine many of you are familiar with the difference between Ruby (a beautiful language representing the best pragmatic balance between Smalltalk’s elegance and C’s ubiquity) and Rubby (a horrendous mishmash of abominations in the style of all scripting languages, glommed together by finding nearly-compatible corner cases).

I also make the same distinction between Open Source (an attempt to get the same exploitation of labour as Free Software but without the principles) and Open Sores (the disturbingly wobbly house of cards that arises when collections of developers, none of whom feels empowered to make big changes, individually attach small pieces of mud to the collectively-constructed big ball).

Neither is fair, but both are useful shorthands.

posted by Graham at 10:05  

Sunday, December 28, 2014

In which I resolve

When I was a student I got deeply into GNU and Linux. This has been covered elsewhere on this blog, along with the story that as Apple made the best UNIX, and the lab had NeXT computers, I went down the path of Objective-C and OS X.

I now think that this was because, as an impressionable twenty-something-year-old, I thought that the most important part of the technology was, well, the technology. But I realise now that I want to have taken the other path, and now need to beat across toward it.

The other path I’m talking about is the one where I notice that it’s not programs like those in Debian that are so great, but the licences under which they are distributed. Much of the software in a GNU/Linux distribution is not so good. That makes it much like using software on every other platform. The difference is that I have the right-and hopefully, after a decade of practice, the ability-to do something about it in the case of free software.

I’m certain that GNU is not the best of all systems, though, because the focus has been on the right to make changes, not the capability of making changes. A quick review of the components I can remember in the installation on my MacBook shows that I’d need to understand at least nine different programming languages in order to be able to dive in and address bugs or missing features in the system, holistically speaking. If they’ve given me permission to change how my computer works, they haven’t made it easy.

But as someone who can change software and wants software to be less broken for me and for others, that permission is important. Next year I’ll be looking for more opportunities to work with free software and to make things less broken.

posted by Graham at 20:47  

Wednesday, December 10, 2014

Quotes on JavaScript

Derek Jones, from the PL advent calendar ‘J’ entry:

Javascript would not have existed without the Internet and its ‘design’ must be a contender for the most costly software mistake [ever] made.

Me, 14 months ago:

Fundamentally I fear a world in which programmers think JavaScript is acceptable. Partly because JavaScript, but mostly because when a language is introduced and people avoid it for ages, then just because some CEO says all future websites must use it they start using it, that’s not healthy. Objective-C was introduced and people avoided it for ages, then just because some CEO said all future apps must use it they started using it.

Clearly JavaScript is good enough for a broad set of uses. But then we should ask whether ‘good enough’ means unfurling the Mission Accomplished flag and calling it done. Apparently some people have similar feelings, but also the skill and inclination to do something about it.

posted by Graham at 12:11  

Sunday, December 7, 2014

Object-Oriented Programming in 1714

Here are some excerpts from Leibniz’s La Monadologie (specifically from Daniel Garber and Roger Arlew’s English translation in Discourse on Metaphysics and Other Essays).

THE MONAD, which we shall discuss here, is nothing but a simple substance that enters into composites – simple, that is, without parts.

Thus, one can say that monads can only begin or end all at once, that is, they can only begin by creation and end by annihilation, whereas composites begin or end through their parts.

The monads have no windows through which something can enter or leave. […] Thus, neither substance nor accident can enter a monad from without.

From this we see that if, in our perceptions, we had nothing distinct or, so to speak, in relief and stronger in flavour, we would always be in a stupor. And this is the state of bare monads.

Thus we attribute action to a monad insofar as it has distinct perceptions, and passion, insofar as it has confused perceptions.

But in simple substances the influence of one monad over another can only be ideal, and can only produce its effect through God’s intervention, when in the ideas of God a monad rightly demands that God take it into account in regulating the others from the beginning of things. For, since a created monad cannot have an internal physical influence upon another, this is the only way in which one can depend on another.

But natural machines, that is, living bodies, are still machines in their least parts, to infinity.

And the author of nature has been able to practice this divine and infinitely marvellous art, because each portion of matter is not only divisible to infinity, as the ancients have recognized, but is also actually subdivided without end, each part divided into parts having some motion of their own;

This we see that each living body has a dominant entelechy, which in the animal is the soul; but the limbs of this living body are full of other living beings, plants, animals, each of which also has its entelechy, or its dominant soul.

That’s a small fraction of the complete essay but it’s clear from these extracts that Leibniz saw both the benefit and the drawback to Object-Oriented Programming, and that they were one and the same.

Objects are indivisible atoms, which cannot mess with each other’s insides nor have their own insides messed with. Rather, they have independent existences, unless one of them sends a message to another via the universal actor willing the two into some correlation.

Something appears to be an object in the first instance, because it is an indivisible thing with its own whole definition and purpose. It is actually both a composite, that can be subdivided into other objects with their own definitions and purposes; and it is a component that contributes toward a larger object that has its own definition and purpose.

Scale-variant analogies can get us out of the problem with the object-as-monad. One that has previously been well-explored is Brad Cox’s Software IC, which sees the object take up a position at only one level of abstraction:

  • Component => C instruction.
  • Integrated Circuit => Objective-C Object.
  • Circuit Board => Package or architectural layer.
  • Electronic System => Application.

One that I haven’t yet investigated is the cellular biology analogy introduced by Alan Kay (who also introduced the object-as-monad analogy). He talked about the object as a cell (particularly as a small component of a larger system that has a well-defined boundary across which limited communication occurs), but we can also think about the implications of larger scale order:

  • Cell => Object.
  • Organ => Object.
  • Organism => Object.
  • Society => Object.
  • Population => Object.
  • Biome => Object.

And, as Leibniz said, it’s objects all the way in the other direction: organelles are monads too.

posted by Graham at 01:27  

Sunday, December 7, 2014

An odd thought

An odd thought: I have written software for a computer whose CPU was used as an I/O controller for a computer that I have programmed, whose CPU was used as an I/O controller for a computer that I have programmed. So far, I’m not aware of the i7 being used as an I/O controller.

posted by Graham at 00:49  

Monday, December 1, 2014

Programming language advent

The first article, containing languages beginning with ‘A’, is linked above. I can tell this is going to be a month of reading.

posted by Graham at 08:25  

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