Variable binding and assignment about luna HOT 7 OPEN

• I think immutable brings more complex like:
  • Wether the value is immutable or just the pointer to the value (exactly the value' RAM address) is immutable, or both?
  • If the value is immutable, the container and string types's performence will be more slow. But we can optimise them like Haskell and immutable.js dose.
• It's better to have no uninitialised value, like Golang dose. for example, if we defined a uninitialised variable, the value is already malloced on the heap (or just on the stack), and the value should be a instinct zero value, like 0 for a number, "" for a string, "[]" for a list.
• I like function scope because we can write if condition { let a = 1} else { let a =2 }; print(a).

from luna.

• If we bring immutability, it would be good to let the variables mutate but not the data structures, @tj even mentioned this at #45, besides we can optimise like you said. The opposite doesn't make much sense and if both were immutable Luna would turn into a pure-functional language, which I think it's not it's target.
• That's true, but then the user would have to obligatory declare the type of the variable before the assignment, I find that very strict but it might be less error-prone than having a nil value.
• Yeah, function scope fits better with Luna style, another option is to let loops have their own scope but not the if statement.

from luna.

Put it together:

if some_condition:
  let a = "foo"
else
  let a = 42
end

# what's the type of a? If we have a static linter, it's hard to lint the rest of code with operations to a.

So I think people will not write codes like this, declare the type of variable before assign value to it is acceptable in my opinion. And function scope is a bad choice I thought now (I think most static typed languages have block scope as I can remember).

And certainly the variables must be mutable above. Or we should write codes like this:

let a = if some_condition
  return "foo"
else
  return "bar"
end

This will hard to write code if we have a complex condition and multiple variable to assign, so I agree with you (mutable variable and immutable value like clojure dose).

from luna.

I understand you now, it wouldn't be possible to analyze the program statically with uninitialized variables without a type or function scope.

So we have:

• Mutable variables
• Immutable values
• Block scope

I think that's pretty good. I will leave this open for now though, we got a lot of work haha.

from luna.

Hi can you open some issues about what to do, so people can join this repo quickly, thank you 😊

I saw the issues about what to do, some were to generic ...

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I've added the most urgent thing right now (#77), when I have some more time I will add the rest.

from luna.

👍

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