monkey2/modules/monkey/newdocs/language/enums.md

@manpage Enums

Enums

Enum is a data type containing a set of Int constants.

By default the members will receive values starting from zero and incemented by one for each new member. You can assign a chosen value to each member when declaring them.

Enum myBasicEnum
	a,b,c 'a=0, b=1, c=2
End

Enum myCustomEnum
	a=7
	b=31,c,d 'c=32, d=33
End

The values can be accessed with the postfix member acces operator (.). Enums values are implicitly converted to integral values when assigned to it.

Local i:UInt=myCustomEnum.b

You can also create Enum variables. An Enum variable contains an Int variable in addition to it's constant members (default value is zero).

Bitwise operators (|,&,~) can be used with Enums variables and Enums members to compute combinations. Such Enums most often contain powers of 2 numbers as members! (1,2,4,8,16,32,64,... and 0 if needed).

A bitmask Enum example:

Enum Flags 'a classic Enum. (4 bits bitmask)
	None=0
  A=$0001 'bin OOOI dec 1
  B=$0002 'bin OOIO dec 2
  C=$0004 'bin OIOO dec 4
  D=$0008 'bin IOOO dec 8
End

An enum with modifiers example (in this case the bitwise operators should be used with at least one modifier):

Enum Foo '(modifiers on 5th and 6th bit)
	None=0
	A=1,B,C,D,E,F,G,H,J,K,L,M ' max 15 because the 5th bit is used for modifier
	Modifier_A=$0010 'bin IOOOO dec 16
	Modifier_B=$0020 'bin IOOOOO dec 32
End

For now enums don't accept negative number literals. To assign a negative number you'll have to type a substraction until the bug is resolved.

Enum Foo '(with a negative member)
	Negative=0-1 'instead of -1
	None=0
	A=1,B,C,D,E,F,G,H,J,K,L,M
End