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I honestly think the opposite. When I learned generators from Python the understanding of “a function that yields instead of returns” was very easy to grasp. A

I honestly think the opposite. When I learned generators from Python the understanding of “a function that yields instead of returns” was very easy to grasp. And considering I already knew how functions worked & what their syntax was this was just an extra step (rather than starting from scratch). ECMAscript have taken a similar path to Python here. This could also be because my mental model is they are just functions that have the ability to return to the stack at a later point in time, rather than “running to completion”.

throwawaymaths 4y ago
Well maybe it's my small brain but I remember in math class it was very important that "a function has only one return value", which probably is part of why I was confused.
- WorldMaker 4y ago
  Technically generators still only have one return value: an Iterable. That Iterable represents an object with a "next()" callback and you can entirely write by hand Iterables as simple dumb objects if you like. (The generator function syntax makes it a lot easier to build complex state machines, but most languages aren't going to stop you if you prefer to write your state machine by hand.)
- Dylan16807 4y ago
  The mathematical definition of function also rejects all side-effects, so probably not the best thing to use around programming. Call it a routine instead?
  - int_19h 4y ago
    We had a descriptive yet very generic term for function-like stuff: "subprogram".
    - throwawaymaths 4y ago
      Oh man that brings memories: gosub in basic (though I think it was subroutine). Also Pascal had procedures vs functions.
Waterluvian 4y ago
Yup, I can see that! One issue I have is that my model of the stack is that "it's a literal _stack_ of frames. You pop them one by one, executing them." What happens to a frame that you pause? Does it get set aside? Is it still on the stack?
- hundt 4y ago
  This article[0] and a clarifying comment[1] answer the question for JS. I think it's the same for Python. Apparently your model (which was mine, too) is out of date! [0] https://hacks.mozilla.org/2015/05/es6-in-depth-generators/ https://hacks.mozilla.org/2015/05/es6-in-depth-generators/ [1] https://hacks.mozilla.org/2015/05/es6-in-depth-generators/#comment-17692 https://hacks.mozilla.org/2015/05/es6-in-depth-generators/#c...
- int_19h 4y ago
  This kind of thing shows up around several other related PL features, so much so that it has a name: https://wiki.c2.com/?SpaghettiStack https://wiki.c2.com/?SpaghettiStack

throwawaymaths 4y ago

Well maybe it's my small brain but I remember in math class it was very important that "a function has only one return value", which probably is part of why I was confused.

WorldMaker 4y ago
Technically generators still only have one return value: an Iterable. That Iterable represents an object with a "next()" callback and you can entirely write by hand Iterables as simple dumb objects if you like. (The generator function syntax makes it a lot easier to build complex state machines, but most languages aren't going to stop you if you prefer to write your state machine by hand.)
Dylan16807 4y ago
The mathematical definition of function also rejects all side-effects, so probably not the best thing to use around programming. Call it a routine instead?
- int_19h 4y ago
  We had a descriptive yet very generic term for function-like stuff: "subprogram".
  - throwawaymaths 4y ago
    Oh man that brings memories: gosub in basic (though I think it was subroutine). Also Pascal had procedures vs functions.

Waterluvian 4y ago

Yup, I can see that! One issue I have is that my model of the stack is that "it's a literal _stack_ of frames. You pop them one by one, executing them." What happens to a frame that you pause? Does it get set aside? Is it still on the stack?

hundt 4y ago
This article[0] and a clarifying comment[1] answer the question for JS. I think it's the same for Python. Apparently your model (which was mine, too) is out of date! [0] https://hacks.mozilla.org/2015/05/es6-in-depth-generators/ https://hacks.mozilla.org/2015/05/es6-in-depth-generators/ [1] https://hacks.mozilla.org/2015/05/es6-in-depth-generators/#comment-17692 https://hacks.mozilla.org/2015/05/es6-in-depth-generators/#c...
int_19h 4y ago
This kind of thing shows up around several other related PL features, so much so that it has a name: https://wiki.c2.com/?SpaghettiStack https://wiki.c2.com/?SpaghettiStack