Check if all fields in a record have been set.

← Operators and Expressions · Ref: Q1087

Check if a record is set with the ? operator:

  if full?
    stdout.println("set")

'default operator ?' uses ALL-field (flattened-aggregate) semantics — it is true only if EVERY field is set, own and inherited. A single unset field makes the whole object unset. Use 'override operator ?' if you need different logic.

See Q1089 for custom override operator ?.

Example

defines module qa.operators.checkrecordfullyset

  defines class

    AppConfig
      dbHost <- String()
      dbPort <- Integer()
      apiKey <- String()

      AppConfig()
        ->
          dbHost as String
          dbPort as Integer
          apiKey as String
        this.dbHost :=: dbHost
        this.dbPort :=: dbPort
        this.apiKey :=: apiKey

      AppConfig()
        -> dbHost as String
        this.dbHost :=: dbHost

      default operator

  defines program

    CheckRecordFullySetDemo()
      stdout <- Stdout()

      //Fully set config
      full <- AppConfig("db.prod", 5432, "secret-key-123")
      stdout.println(`Full config set?: ${full?}`)

      //Partially set — only dbHost provided
      partial <- AppConfig("db.dev")
      stdout.println(`Partial config set?: ${partial?}`)

      //Empty — no fields set
      blank <- AppConfig()
      stdout.println(`Empty config set?: ${blank?}`)

Common mistakes

E01073 — EK9 has no 'null'; use the '?' operator to test whether an object is set. See ek9 -h E01073 for details.

Incorrect:

${full != null}

Correct:

${full?}

Other ways to ask this

Test whether an object is fully initialised using ?
Determine if a record has any unset fields
In Java I'd check each field for null. How do I check if an EK9 object is set?
I need to verify that a config object has all required values before using it

Coming from another language?

Java: manual null checks per field, or Bean Validation @NotNull. Python: all(v is not None for v in vars(obj).values()). EK9: ? operator with default (all-field) or custom (override) semantics.

Keywords: validate, isSet, ?, check, operator, initialised, set