[rramadass]

> so the program we write is a meta program that constructs the OO system procedurally. The system is not visible in the program text, it is created as a side effect of running the procedures and remains invisible,

Great way of stating it! Most people who cargo-cult "OO is bad" don't get this.

> a good OO system will, by necessity, be highly indirect compared to the program text. A good OO system will also have sufficient benefits that this trade-off is very much worthwhile,

Very true. This is the reason OOD/OOP has been a great success that has led to the explosion of software that we take for granted today.

> My approach to the tradeoff is to remove the indirection in the program text by making it possible to directly express components, connectors and systems in the program text, rather than having to build them all procedurally.

At language source level (eg. DSL) or binary component level (needs runtime support a la COM) ?

[mpweiher]

> Most people who cargo-cult "OO is bad" don't get this [that OO programs are meta programs that build the system].

Alas, many people who advocate OO don't get this either, and in particular they don't see this as a problem to be solved.

Having to do things indirectly is not a good state of affairs. See "goto statement considered harmful". [1]

It is similar to the way we had to work with text editors made for printing terminals: "...requires a mental skill like that of blindfold chess; the user must keep a mental image of the text he is editing, which he cannot easily see, and calculate how each of his editing command `moves' changes it." [2]

> OOD/OOP has been a great success that has led to the explosion of software that we take for granted today.

Yes, people forget that the problems we are now having are the ones that are due to OO success.

> At language source level (eg. DSL) or binary component level (needs runtime support a la COM)

Language level. At the systems level we know how to build these types of system (COM, Smalltalk, Objective-C, Unix pipes and filter, REST, notification systems, ...), what we lack is the ability to express them in the program text: https://objective.st/

[1] https://homepages.cwi.nl/~storm/teaching/reader/Dijkstra68.p...

[2] https://www.gnu.org/software/emacs/emacs-paper.html

[rramadass]

> Having to do things indirectly is not a good state of affairs.

One key point to note here is that "Indirection" is often the mechanism used to design and express an "Abstraction". Given that Abstraction is the key to taming complexity and building large Systems they often go together i.e. Indirection becomes a key element in the design of Abstractions. It is only the non-designer of the Abstraction/Indirection who finds it hard to understand the System in the absence of Documentation/Communication.

[mpweiher]

Yes and no.

Yes, indirection in the source "abstraction" is the way to get to a new abstraction.

However, the result has to be an actual abstraction for that to work, and it often isn't. Often it's just indirection. And once you have the new abstraction, you have to be able to express yourself using that abstraction with little or no leakage.

For example, the "procedure" abstraction works that way, we really and truly don't have to care how it is constructed from assembly language instructions roughly 99.999% of the time.

But here's the kicker: since the actual abstraction mechanism in our languages is procedural, we can only create essentially procedural abstractions. For all other kinds of abstractions, the leakage is close to 100% and we are left with just indirection.

In the code.

Which means we need to take our abstractions and hand-compile them to fit our procedural languages, which we do with varying degrees of deftness. And then mechanisms of communicating the actual but mostly implicit "source" program become crucial, as you point out.

I'd rather be able to create and express those abstractions in the code itself. And then be able to program with those abstractions, rather than having to program in the target language of the human compiler.

[rramadass]

> But here's the kicker: since the actual abstraction mechanism in our languages is procedural, we can only create essentially procedural abstractions. For all other kinds of abstractions, the leakage is close to 100% and we are left with just indirection.

Not quite true. "Abstraction" is what you imagine/design according to your needs and treat as a "Single Concept" (eg. a Design Pattern). The fact that it is made out of more granular elements i.e. machine instructions/language statements/procedures for a state machine does not change your ability to reason and work with abstractions at a higher level. While there maybe some "leakage" (mainly when things fail/need for performance) it is by no means total.

Also many people often equate Abstraction with Indirection since the latter is so prevalent in defining the former. But they are different concepts and have to be treated as such.