When I try to run this example from the docs:

x = 3: y = 4: GOSUB @add
PRINT result
END

@add
result = x + y
RETURN

It fails with an error:

ERROR: 2:7: Undefined variable result

I think this might be a result of static single-pass variable checking since when I run the program with the slight change below to print in the subroutine, it still fails without ever printing:

x = 3: y = 4: GOSUB @add
PRINT result
END

@add
result = x + y
PRINT result
RETURN

I'm not sure what the intended behavior is, but as it stands I think the example needs to declare the result variable before calling the subroutine.

DIM result AS INTEGER
x = 3: y = 4: GOSUB @add
PRINT result
END

@add
result = x + y
RETURN