Maybe I am? How is it possible to abstract without encapsulation? And also, how is it possible to encapsulate without abstracting some concept (intentionally or not) contained in that encapsulation? I can't really differentiate them, in the context of naming/referencing some list of CPU operations.
I'm using the industry definition of abstraction [1]:
> In software, an abstraction provides access while hiding details that otherwise might make access more challenging
I read this as "an encapsulation of a concept". In software, I think it can be simplified to "named lists of operations".
> Historically pure machine code with jumps etc lacked any from of encapsulation as any data can be accessed and updated by anything.
Not practically, by any stretch of the imagination. And, if the intent is to write silly code, modern languages don't really change much, it's just the number of operations in the named lists will be longer.
You would use calls and returns (or just jumps if not supported), and then name and reference the resulting subroutine in your assembler or with a comment (so you could reference it as "call 0x23423 // multiply R1 and R2"), to encapsulate the concept. If those weren't supported, you would use named macros [2]. Your assembler would used named operations, sometimes expanding to multiple opcodes, with each opcode having a conceptually relevant name in the manual, which abstracted a logic circuit made with named logic gates, consisting of named switches, that shuffled around named charge carriers. Say your code just did a few operations, the named abstraction for the list of operations (which all these things are) there would be "blink_light.asm".
> If you pretend the train is actually going 80.2 MPH instead of somewhere between 80.1573 MPH to 80.2485 MPH which you got from different sensors you don’t need to do every calculation that follows twice.
I don't see this as an abstraction as much as a simple engineering compromise (of accuracy) dictated by constraint (CPU time/solenoid wear/whatever), because you're not hiding complexity as much as ignoring it.
I see what you're saying, and you're probably right, but I see the concepts as equivalent. I see an abstraction as a functional encapsulation of a concept. An encapsulation, if not nonsense, will be some meaningful abstraction (or a renaming of one).
I'm genuinely interested in an example of an encapsulation that isn't an abstraction, and an abstraction that isn't a conceptual encapsulation, to right my perspective! I can't think of any.
[1] https://en.wikipedia.org/wiki/Abstraction_(computer_science)
[2] https://www.tutorialspoint.com/assembly_programming/assembly...
> I can't think of any.
Incorrect definition = incorrect interpretation. I edited this a few times but the separation is you can use an abstraction even if you maintain access to the implementation details.
> assembler
Assembly language which is a different thing. Initially there was no assembler, someone had to write one. In the beginning every line of code had direct access to all memory in part because limited access required extra engineering.
Though even machine code itself is an abstraction across a great number of implementation details.
> I don't see this as an abstraction as much as a simple engineering compromise (of accuracy) dictated by constraint (CPU time/solenoid wear/whatever), because you're not hiding complexity as much as ignoring it.
If it makes you feel better consider the same situation with 5 senators X of which have failed. The point is you don’t need to consider all information at every stage of a process. Instead of all the underlying details you can write code that asks do we have enough information to get a sufficiently accurate speed? What is it?
It doesn’t matter if the code could still look at the raw sensor data, you the programmer prefer the abstraction so it persists even without anything beyond yourself enforcing it.
IE: “hiding details that otherwise might make access more challenging”
You can use TCP/IP or anything else as an abstraction even if you maintain access to the lower level implementation details.
I genuinely appreciate your response, because there's a good chance it'll result in me changing my perspective, and I'm asking these questions with that intent!
> You are thinking of assembly language which is a different thing. Initially there was no assembler, someone had to write one.
This is why I specifically mention opcodes. I've actually written assemblers! And...there's not much to them. It's mostly just replacing the names given to the opcodes in the datasheet back to the opcodes, with a few human niceties. ;)
> consider the same situation with 5 senators X of which have failed
Ohhhhhhhh, ok. I kind of see. Unfortunately, I don't see the difference between abstraction and encapsulation here. I see the abstraction as being speed as being the encapsulation of a set of sensors, ignoring irrelevant values.
I feel like I'm almost there. I may have edited my previous comment after you replied. My "no procrastination" setting kicked in, and I couldn't see.
I don't see how "The former is about semantic levels, the later about information hiding." are different. In my mind, semantic levels exist as compression and encapsulation of information. If you're saying encapsulation means "black box" then that could make sense to me, but "inaccessible" isn't part of the definition, just "containment".
> How is it possible to abstract without encapsulation.
Historically pure machine code with jumps etc lacked any from of encapsulation as any data can be accessed and updated by anything.
However, you would still use abstractions. If you pretend the train is actually going 80.2 MPH instead of somewhere between 80.1573 MPH to 80.2485 MPH which you got from different sensors you don’t need to do every calculation that follows twice.