Comment by lispm | Hacker News Reader

Comment by lispm | Hacker News Reader

Parent Full thread

> Pushing items onto a stack isn't inherently a prepend operation.

a stack has no idea of "prepend" or similar. It's defined by abstract like operations PUSH, POP, IS-EMPTY, MAKE-STACK. How it is implemented is an implementation detail.

> It's generally a "put it on an end" operation,

Which you made up. There is nothing "generally" like that.

> meaning you could append it. Now, with a linked list that would be slower,

and to append would be unnecessary.

> So if I do implement a simple stack, I implement it with a vector (example[1]).

That's a simple "bounded" & "fixed size" stack.

> I'm a professional.

Okay. ;)

> Yes, I know the answer you're fishing for is "immutability"

That would be one answer. Can you think of more?

> > Pushing items onto a stack isn't inherently a prepend operation.

> a stack has no idea of "prepend" or similar. It's defined by abstract like operations PUSH, POP, IS-EMPTY, MAKE-STACK. How it is implemented is an implementation detail.

You say that as if the fact that it's an implementation detail means it doesn't matter.

Implementation details do, in fact, matter.

> > It's generally a "put it on an end" operation,

> Which you made up. There is nothing "generally" like that.

So you're saying that stacks don't have a "push" operation? Or that you don't understand what "push" does?

> > meaning you could append it. Now, with a linked list that would be slower,

> and to append would be unnecessary.

Literally picking and quoting parts of two sentences out of context to state the obvious as if it's a response to anything I said in context is a new low even for you.

> > So if I do implement a simple stack, I implement it with a vector (example[1]).

> That's a simple "bounded" & "fixed size" stack.

No, it's not. Are you aware that vectors can be resized?

> > Yes, I know the answer you're fishing for is "immutability"

> That would be one answer. Can you think of more?

I'm not going to make your argument for you. If you have something to say, say it.

Reply on news.ycombinator.com