Enum's type

[abakoboParticipant]

-Are enums 32bit Uint or 32 bit signed Int? I can see an issue where it says ints can’t have negative literal.. (https://github.com/blitz-research/monkey2/issues/138). It looks like in C++ it can have negative members, wich can be a problem for importing external enums.

-Are enums primitive types? (I suppose not)

This is for documentation purpose.

[TomToadParticipant]

You could cheat a bit and use twos compliment

Monkey

[crayon-5cba166580d97833578721 inline="true" ]Enum Flag MyNum = $FFFFFFFF End

1 2 3

[crayon-5cba166580d97833578721 inline="true" ]Enum Flag     MyNum = $FFFFFFFF End

[/crayon]

is equivalent to C++

Monkey

[crayon-5cba166580d9d658687119 inline="true" ]enum class Flag { MyNum = -1 };

1 2 3 4

[crayon-5cba166580d9d658687119 inline="true" ]enum class Flag {     MyNum = -1 };

[/crayon]

To find the twos compliment of a signed Int, you can use Print Hex(UInt(-1)) in Monkey2

[abakoboParticipant]

Thanks for the trick!

I still wonder if enums are primitive types (strings are so may be..) and if enums (will) have uint or int members. So I can make a correct description in the docs. (Looking at enum.monkey2 & values.monkey2 did not help me)

[TomToadParticipant]

An Enum will compile to an opaque enum class in the c++ source which uses a signed int for its base. For some reason, M2’s Enum will not accept negative values. I think this might be a parser bug as I can do this

Monkey

#Import"<std>" Using std.. Enum Direction up = 0-10, down, left, right, end Function Main() Local direction := Direction.down If direction = Direction.up Print "You are moving up" Else Print "You are not moving up" Endif End

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

#Import"<std>"   Using std..   Enum Direction up = 0-10, down, left, right, end   Function Main() Local direction := Direction.down If direction = Direction.up Print "You are moving up" Else Print "You are not moving up" Endif End

And it works as expected. (much easier to understand than the $FFFFFFFF hack I posted earlier)

[Author]

Posts