E07630: operator cannot be used on an Enumeration in this way

What went wrong

An operator (or method) is applied to the ENUMERATION TYPE itself, for example '$CardSuit' or 'CardSuit > CardSuit.Hearts'. The type is not a value: operators apply to the enumeration's values, such as 'CardSuit.Hearts' or a variable that holds one.

Worked examples

Compilable examples demonstrating this error and the correct fix:

• ek9 -q 99 (How do I create an enumeration in EK9?)

What works on a value

An enumeration's values are ordered (in declaration order), so the comparison operators (<, <=, >, >=, ==, <>, <=>) work on them, as do '$' (the name of the value), '?', '#?' and '#<' / '#>' (the first and last value). Iterate the type itself with 'for suit in CardSuit' or 'cat CardSuit'.

How to fix it

1. Apply the operator to a value: CardSuit.Hearts, or a variable holding one
2. To visit every value, iterate the type: for suit in CardSuit

Common causes

• Writing the type name where a value was meant
• Expecting '$' on the type to list its values

See also

• E07630: operator applied to the enumeration type (this error)
• E07620: operator not defined for type

Examples

Every example is compiled by the EK9 compiler: the first fails exactly as captioned, the others fix it.

Fails with E07630: operator cannot be used on an Enumeration in this way

#!ek9
defines module error.e07630.bad

  defines type

    CardSuit
      Hearts
      Diamonds
      Clubs
      Spades

  defines function

    describeSuits()
      stdout <- Stdout()

      //CardSuit is the type; '$' applies to one of its values
      stdout.println($CardSuit)

Fixed: Apply the operator to a value of the enumeration

#!ek9
defines module error.e07630.good

  defines type

    CardSuit
      Hearts
      Diamonds
      Clubs
      Spades

  defines program

    DescribeSuits()
      stdout <- Stdout()

      //Every value of the enumeration, in order
      for suit in CardSuit
        stdout.println($suit)

      //Operators apply to values, and the values are ordered
      hearts <- CardSuit.Hearts
      stdout.println($hearts)
      stdout.println($(hearts < CardSuit.Spades))

Questions and answers

These Q&A entries show E07630 and its fix:

• Q99: How do I create an enumeration in EK9?