How do I name class fields without triggering E11031?

← Variable Naming Rules and Conventions · Ref: Q925

Class fields follow the same banned name rules as all variables. Use names that describe what the field represents in the domain model.

EK9 bans exactly 12 non-descriptive names (E11031): temp, tmp, flag, flg, data, dat, object, obj, value, val, buffer, buf. These are case-insensitive. Names like status, state, config, handle, str, num, item, result, input, output, count, index, list, map, set, key, type, param, arg, var, ret, res are NOT banned.

Separately, E11032 bans operator keywords as variable names: empty, length, contains, abs, sqrt, close, matches.

INSTEAD OF BANNED FIELDS:

- 'val' -> 'orderTotal', 'measurementReading'
- 'tmp' -> 'swapHolder', 'intermediateResult'
- 'dat' -> 'sensorPayload', 'configEntry'
- 'buf' -> 'readChunk', 'outputAccumulator'

ALWAYS ALLOWED EXCEPTIONS:

- Single-character: x, y, z, i, j, k (math variables, loop counters)
- Compound words: connectionState, errorCount, dataSource
- Domain descriptive: customerName, orderTotal, retryLimit

Example

defines module qa.naming.inclasses

  defines class

    <?-
      Shows descriptive field naming in a class.
    -?>
    SensorDevice
      sensorId as String: String()
      currentReading as Float: Float()
      isCalibrated as Boolean: Boolean()

      SensorDevice()
        -> deviceId as String
        sensorId :=: deviceId

      recordMeasurement()
        -> measuredValue as Float
        currentReading := measuredValue
        isCalibrated := true

      operator $ as pure
        <- rtn as String: `${sensorId}: ${currentReading}`

      override operator ? as pure
        <- rtn as Boolean: isCalibrated?

  defines program

    InClassesDemo()
      stdout <- Stdout()

      // GOOD: descriptive field names inside class
      sensor <- SensorDevice("TH-001")
      sensor.recordMeasurement(22.5)
      stdout.println($sensor)

      // Compound words: ALLOWED as locals too
      errorCount <- 0
      dataSource <- "network"
      stdout.println(`Errors: ${errorCount}, Source: ${dataSource}`)

      // Single-char math: ALLOWED
      x <- 1.0
      y <- 2.0
      stdout.println(`Position: ${x}, ${y}`)

Common mistakes

E11031 — The name 'data' is one of the 12 banned non-descriptive variable names, so declaring 'data' triggers E11031 — use a descriptive name like dataSource. See ek9 -h E11031 for details.

Incorrect:

      data <- "network"
      stdout.println(`Errors: ${errorCount}, Source: ${data}`)

Correct:

      dataSource <- "network"
      stdout.println(`Errors: ${errorCount}, Source: ${dataSource}`)

Keywords: class, naming, E11031, property, banned, field