E07330: 'default' is required in this 'switch' expression

What went wrong

Your switch EXPRESSION (used in assignment) is missing a default case. Switch expressions must return a value for ALL possible inputs.

Worked examples

Compilable examples demonstrating this error and the correct fix:

• ek9 -q 788 (Why does a switch expression require a default case in EK9?)

Rationale

Switch EXPRESSIONS must be exhaustive to guarantee a return value.

How to fix it

1. Add default case that returns a value

Common causes

• Forgot default case
• Not realizing expression requires exhaustive coverage

See also

• E07330: switch expression missing default (this error)
• E07320: switch statement missing default
• E07310: enum switch missing cases

Examples

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

Fails with E07330: 'default' is required in this 'switch' expression

#!ek9
defines module error.e07330.bad

  defines function

    sizeOf()
      -> count as Integer
      <- rtn as String: String()

      //Without a default, size has no value when count is 10 or more, or unset
      size <- switch count
        <- text as String?
        case < 10
          text: "small"

      rtn: size

Fixed: Add a default

#!ek9
defines module error.e07330.good

  defines function

    sizeOf()
      -> count as Integer
      <- rtn as String: String()

      size <- switch count
        <- text as String: String()
        case < 10
          text: "small"
        default
          text: "large"

      rtn: size

Questions and answers

These Q&A entries show E07330 and its fix:

• Q788: Why does a switch expression require a default case in EK9?