Bump, it's been a week. It's literally just one button press to merge.

Before this PR on non flag enums, if a number that does not belongs to the enum is given as an argument, then nil is returned.

After this PR if the enum acts as flag the user can build enum with values outside the declared constants. Maybe a bitwise & should be applied before returning the enum value.

Also, if this is 0, and there is no 0 as enum value, I would expect nil to be returned.

Hi,

Thanks for the PR but it's not quite right. The idea is that from_value validates that the given value is valid. For example, given:

@[Flags]
enum ColorFlags
  Red = 1
  Green = 2
  Blue = 4
end

Then:

ColorFlags.from_value?(1) # => Red
ColorFlags.from_value?(3) # => Red, Green
ColorFlags.from_value?(5) # => Red, Blue
ColorFlags.from_value?(7) # => Red, Green, Blue

# But...
ColorFlags.from_value?(8) # => nil
ColorFlags.from_value?(9) # => nil
...

So this is not the same as new.

@asterite I have been looking into this more, and have been working on updating my implementation, I have a question though, in your above example from_value?(9), shouldn't that return Red since the bitwise & of 9 and 1 == 1?

Maybe use some sort of base-of-x math?

@asterite @bcardiff I made some updates, I had one outstanding question above regarding the example you gave.

@bmulvihill 9 is not a valid value, because yes, 1 is in it, but it's not an exact combination of all the enum values. One way to implement this, I guess, is to subtract each of the enum values from the given value, if the value is greater than the enum value. In the end the value should end up being zero. I don't know if there's another way to do this.

Another approach would be to use bitwise operators to valid the value.

Given

@[Flags]
enum ColorFlags
  Red = 1
  Green = 2
  Blue = 4
end

if the mask = ColorFlags::Red | ColorFlags::Green | ColorFlags::Blue is built,
then for any v value given to from_value?(v) if v & mask != v it means there are some unexpected flag values.
There is a corner case with 0 though. 0 & mask == 0 but might not be a valid enum value.

@bcardiff I implemented a mask to determine valid values, the behavior now seems to be what is expected.

GTG?

@bmulvihill Thank you! ❤️