P.S. I have no idea why you're so skeptical that the Sinclair Executive can execute other than left-to-right, to the point of reading an example where the operations are executed left-to-right as evidence that it can execute in another order. But if you really cannot accept, due to some weird glitch in your programming or whatever, what about:

• The Monroe 20. The example is typed in as 1 + 2 × 4 - 5 ÷ 6 = and the result is given as 1.16 (repeating). That has been executed left-to-right; the result would be 8.16 (repeating) if executed with the usual operator precedence.

• The Montgomery Ward P300. An example is typed in as 8.3 + 2 ÷ 4 - 6.8 =, with the result given being -4.225. That has been executed left-to-right; the result would be 2 if executed with the usual operator precedence.

• The Omron 88. An example is typed in as 98 + 76 - 54 × 32 ÷ 10 =, with the result being given as 384. That has been executed left-to-right; the result would be 1.2 if executed with the usual operator precedence.

And to round it all out here is an issue of Electronic Design with an article (read p41, "Which Arithmetic") that explicitly says that, in 1978, "all scientific calculators" except those of TI and HP used immediate execution. I dunno how many sources for this you need; I'm guessing you'll find some way of deciding that when a magazine says "all scientific calculators except TI and HP" it means something completely different.

I mean, it's just like I said: the basic, four-function calculators are all like this. Scientific Calculators used to all be like this, until technical developments were made that allowed otherwise. Feel free to browse more manuals on that website if you want, it's quite interesting! If you were to, you'd have a better understanding of how these calculators - which I practised with in primary school, but which you, because you didn't, assert don't exist - actually work.

As an extra favour to you, I found the manual of the scientific calculator I had at home when I was growing up - this is what I used whenever I needed a calculator for homework until we were instructed to get a specific calculator, from some specific school year. That calculator was:

• The Casio fx-110. And what do you know, it has an example of typing the keys: 56 × 3 - 89 ÷ 5.2 + 63 = and printing the answer 78.19230769. The answer, if executed with usual operator precedence, would be 213.88461538.

So indeed, it's not just basic calculators. So let's go from here: there were millions and millions of calculators sold on which, if you type 2 + 3 × 5 it would give the answer 25.

Nope! I covered the past as well Mr. Abysmal Reading Comprehension

"You are continuously wrong all the time" is in the present tense which, by your logic, only covers the present moment. "All the time" can no more change that than "never" can change that.

The second clause is only a guess from you, so I don't really care about it.

There is no “=” button on the Sinclair Executive, and you aren’t saying the += means equals

Yes I am!

It can't mean equals if part of its function is addition. "Add, and update the display with the current accumulated value" (which is what the button actually does) does not mean "update the display with the current accumulated value". That is only part of its meaning; saying that something means only part of its meaning is simply not correct.

I’m saying omitting that keypress will evaluate a+bxc, instead of (a+b)xc.

I know you are. And that claim is not supported by the manual. That sequence of keypresses is not there.

All my calculators work the same way, even the one I have that doesn’t have brackets keys (though according to you it doesn’t have a stack if it doesn’t have brackets keys 😂 )

Still waiting for that video!

If you’d proven your assertion about the Sinclair Executive you would have:

• An example in the manual of it obeying order of operations in violation of right to left execution; or

Go ahead and type in a+=bxc+=, I’ll wait.

This was not an example in the manual of it obeying order of operations in violation of right to left execution, so you have failed to provide that evidence.

• The specifications saying how much stack memory it had; or

You know the stack isn’t hardware, right? Go ahead and find any calculator manual which specifies how big the stack is.

A stack requires hardware to operate; it requires memory. In early calculators, the stack was, in fact, a dedicated area of memory, because the amounts of memory we are talking about are so small that there was no way to dynamically assign memory to different functions.

You would not necessarily find the stack size in the manual, but you would expect to find it in the technical specifications. As an example of the kind of evidence you're looking for this guide to using the HP-41 specifically mentions its 5-level stack. Note that this calculator was introduced in 1979, 7 years after the Sinclair Executive, and had 64 memory registers (in the original model; this could be expanded).

So, off you go.

• A video of someone using it to show it using order of operations in violation of right to left execution; or

You just tried to deflect this. I'm quite happy to post a video showing how my free calculator works, but you indicated you would dismiss it as a "chain calculator". If you give any indication that you're not going to dismiss it, I'll happily provide one. For now, we are talking about the evidence you could provide.

• An emulator where you can see the same.

You’re arguing about calculators that precede the internet, and you’re expecting an emulator to exist for it

Weird thing to be skeptical of. Here's a link to an emulator for the Sinclair Cambridge

Note that you can type in the exact same sequence of keys we're talking about on this calculator: 2 + 3 × 5 =, and it will produce 25.

That is four different ways you could have demonstrated that this calculator has the capability to operate other than in immediate execution mode, and your responses were:

1. deflect
2. deflect, and an incorrect assertion about how early stacks worked
3. deflect
4. deflect, and an incorrect preconception about the emulation of early calculators.

Instead you have an example in the manual where the calculator executes strictly left to right,

No it doesn't!

I'll explain this once more. In the manual, the calculation we are discussing is rendered as 2.6 + 5 + x 9.1. We can tell the calculator executes this left-to-right because it gets the answer 69.16 and not 48.1. You are saying that, if a different sequence of keys had been pressed, then the calculator would do something produce 48.1 You have no evidence for that claim, because that sequence of keys is not in the manual, and nor is that result. I have evidence that it cannot happen, because it is impossible with the calculator's hardware.

Oh look. it remembers the division whilst we enter other things!

Yes, the calculator has an operator register. Explain what I have said that you think this contradicts, and why. Note that it cannot remember more operators.

And look, it remembers four numbers. Also, (a+b)/(c+d) has three operands, and somehow it manages to remember all of them

No, it can't. You enter four numbers, but it only remembers three (the one you're currently entering, the accumulated total, and one manually stored number). You can see how it works from the diagram: at each step, the next number is calculated from those three values.

(a+b)/(c+d) has four operands (did you get operand confused with operator?).

It doesn't need to remember them all for the same reason that when you add up 4 + 6 + 23 + 21 + 5 + 8 + 1 you only need to remember the running total ("the accumulator"), not all 7 operands in the sum.

Normally is a(b+c)+d(e+f)=, but sure, go ahead and explain to us how you can evaluate that “normally” without brackets and without splitting it up.

That's not an evaluation, that's an expression with an equals sign at the end, which doesn't make any sense. The original expression has brackets, so I'm not sure what you mean by "without brackets" unless you want me to rewrite it in a notation that doesn't use brackets. I just meant I'd first add b to c, then add e to f, then multiply those two values by their respective coefficients. No splitting needed.

Brackets are notation; RPN doesn’t use them

and so is the missing + in 2+3, and yet we know it’s there, which you have acknowledged you saw in the textbook 🤣🤣🤣

If we were talking about whether you need a plus-sign before a number to express that it is positive, the expression 2+3 and its evaluation to 5 would be sufficient evidence that you do not. Likewise, when we are discussing whether you need brackets to express that addition is to be performed before multiplication, the expression 2 3 + 5 x in RPN and its evaluation to 25 is sufficient to show that no brackets are needed. There are no brackets in the RPN expression 2 3 + 5 x, and its correct value is 25.

Nope, I’ve explicitly said they are required

You've said that the brackets can be "built-in" meaning, according to you, that there are no buttons for them. Look man, either the brackets buttons are required for evaluating complex expressions, or they aren't. Make your mind up, then we can talk about this some more.

Bet you’ll deflect

says person

You know, every time you say "says person", it actually is a deflection. So thanks for proving that one.

Just to recall: I asked, "if you mean something else than brackets buttons, explain what" and you did not do that. Indeed, you didn't even quote that sentence in your reply where you seem to delight in quoting every single clause on its own. Interesting!

a problem such as (a+b)c + (d+e)f cannot be done as a simple calculation

that’s because it has no brackets keys dude

I’d write it out in rpn

Is it an RPN calculator?

No, it's not, but you didn't ask how I'd calculate it on this specific calculator, which I have always agreed can't do it. Rather, you just asked how I'd calculate it without splitting it up, and without using brackets keys. I'd write it out in RPN, which does not require brackets keys, and does not need to split it up.

This was your point that you raised, genius, and you forgot what it was about. Embarrassing.

You’re saying that example tells you what would happen when the += key was not pressed a second time?

Nope

Finally!

No it doesn’t! It puts (a+b) on the stack

You really need to get better at explicitly distinguishing between strings of symbols and their numeric counterparts. What it does is it puts the result of adding b to a into the accumulator.

So I’m pretty sure according to you that proves that it obeys the order of operations, right?

Nope

But you insist that the Sinclair Executive obeys the order of operations. And MS Calc behaves the same as the Sinclair Executive. They behave exactly the same - if they don't, find an example of the Sinclair Executive behaving differently. If they do, what's your problem with MS Calc? It's behaving the same as a physical calculator.

Guess what happens you you omit the circled keypress..

Well, it would be a guess, wouldn’t it. That’s all you have, a guess.

Nope. I have a calculator which behaves the exact same way

Try to keep up. We're talking about the Sinclair Executive. Is your calculator one of those? No?! So indeed, you're guessing about how the Sinclair Executive works without that keypress.

So why does ms calc work in the exact same way as an immediate execution calculator?

[not an answer to the question]

I'm just going to replace your deflections with some text like that, to show where you've failed to answer.

It’s right there in the manual that you have to do that second press to put it in brackets

And yet the manual does not say "you have to do that second press to put it in brackets" and there is no example without that second press to compare to soooooo... you're guessing.

and yet, all different parts behaving in different ways.

Uh huh! Keep going!

I know you haven’t worked out where the brackets go!

[not working out where the brackets go]

Thanks for not playing!

We teach them that ab=(axb)

So, you do teach them the concept of implicit multiplication. You just don't use the same words. Cool! Thank fuck for that!