union type examples.py

# Example 1
@task
def task1() -> Union[int, str]:
  return "hello world"

--> Outputs literal:
{
  "union": {
    val: <literal scalar string "hello world">
    index: 1
  }
}

@task
def task2(a Union[MyInt, int, str]):
  ...

task2(a=task1())
--> Inputs literal:
"a": {
  "union": {
    val: <literal scalar string "hello world">
    index: 2, <<<<--- this is figured out by the backend runtime
  }
}
  
# example 2
@task
def task1() -> int:
  return 5

--> Outputs literal:
{
  <literal scalar int 5>
}

@task
def task2(a Union[MyInt, int, str]):
  ...

task2(a=task1())
--> Inputs literal:
"a": {
  "union": {
    val: <literal scalar int 5>
    index: 1, <<<<--- this is figured out by the backend runtime
  }
}
  
# example 3
@task
def task1() -> MyInt:
  ...

--> What will be in the LiteralType? will it just be an int?

@task
def task2(a Union[MyInt, int, str]):
  ...

task2(a=task1())
--> How will the backend compiler match... if both MyInt and int look exactly the same, the backend compiler will have to reject this as unambiguous. Is that what you are proposing?

# example 4
@task
def task1() -> Union[MyInt]:
  return MyInt(5)

--> Outputs literal:
{
  "union": {
    val: <literal scalar int 5>
    tag: "MyInt"
  }
}

@task
def task2(a Union[MyInt, int, str]):
  ...

task2(a=task1())
--> Inputs literal:
"a": {
  # the exact literal as output by task1:
  "union": {
    val: <literal scalar int 5>
    tag: "MyInt"
  }
}