This
great
is
one
+
+
+
!Thisgreatisone! ?
If the operands go the other way, I suppose:
oneisgreatThis!
The stack doesn’t quite work like that. They would get added like this:
This > buffer
great, is, one > stackThen, each + pulls the latest off the stack and operates.
First + would pull ‘one’ as it’s the most recent on the stack.
This page does a good job of explaining: https://www.geeksforgeeks.org/dsa/introduction-to-stack-data-structure-and-algorithm-tutorials/
Edit: you can also see this reflected in the Alt-text:
I NOTATION POLISH REVERSE ❤️Huh, it’s that buffer thing that I didn’t know about and isn’t mentioned in your link (maybe it’s Forth specific?), I use an RPN calculator app, but everything goes on the stack, so “This” would be on the bottom and be popped off last.
Did Randall get this one wrong?
It looks to me that it is either Forth, or implementation specific, not RPN in general. But then again, the meme is about Forth, not RPN
My guess is that POLISH and REVERSE modify the top stack element immediately
But just to nitpick, wouldn’t this parse into “Forth ❤️ I”? Which is to say, aren’t the operands in the wrong order?
But just to nitpick, wouldn’t this parse into “Forth ❤️ I”? Which is to say, aren’t the operands in the wrong order?
No, they’re correct. You’re parsing it wrong.
RPN
data1 data2 function
Neither Forth nor I are actions.
That’s true, but as the Forth is top of stack I’d read it as the subject and I as the object. OFC that’s just how you define the heart-word, but still.
The operand at the top of the stack is used as the second operand for binary operators. Second from the top is used as the first operand.
Here illustrated using
dc, and doing the calculation 3 - 1 and printing the answer with the commandp, getting the result of 2. As we can see here with a noncommutative operation (subtraction), in order to illustrate the point, we get 2, rather than -2.~ dc 3 1 - p 2Color me mystified. Why would you map the verb of an English sentence to anything but a function or method in a computer language expression?
Loved playing with a Forth subset (MUF) in MUD and MUCKs.
