Select the longer warranty period from two product options.

← Operators and Expressions · Ref: Q1216

The >? coalescing maximum operator returns the longer of two Duration values, handling unset gracefully.

  longerWarranty() as pure
    -> left as Duration, right as Duration
    <- rtn as Duration: left >? right

If both durations are set, >? returns the longer one. If one is unset (no warranty info), it returns the available warranty. If both are unset, the result is unset.

This is a COMPARISON operator — it picks the larger value. Do not confuse it with :=? (guarded assignment), which assigns only if the target is unset. See Q1226 for a side-by-side contrast.

See Q1092 for min/max coalescing overview. See Q1210 for <? minimum on Duration.

Example

defines module qa.operators.coalescemax.duration

  defines function

    longerWarranty() as pure
      ->
        left as Duration
        right as Duration
      <- rtn as Duration: left >? right

  defines program

    CoalesceMaxDurationDemo()
      stdout <- Stdout()

      // === BOTH WARRANTIES KNOWN — returns the longer ===

      standardWarranty <- P1Y
      extendedWarranty <- P3Y
      bestWarranty <- longerWarranty(standardWarranty, extendedWarranty)
      stdout.println(`Best warranty: ${bestWarranty}`)

      // === ONE WARRANTY UNKNOWN — returns the available one ===

      knownWarranty <- P2Y
      unknownWarranty <- Duration()
      onlyWarranty <- longerWarranty(knownWarranty, unknownWarranty)
      stdout.println(`Available warranty: ${onlyWarranty}`)

      // === BOTH UNKNOWN — result is unset ===

      missingA <- Duration()
      missingB <- Duration()
      noWarranty <- longerWarranty(missingA, missingB)
      if noWarranty?
        stdout.println(`Warranty: ${noWarranty}`)
      else
        stdout.println("No warranty information available")

Other ways to ask this

How do I find the maximum of two Duration values when one product has no warranty info?
Two product variants have different warranty periods but one might be unspecified — pick the longer.
In Java I'd need null checks before comparing Duration objects. What does EK9 use?
Migrating from C# where I use TimeSpan comparison with nullable checks — what is the EK9 pattern?

Coming from another language?

Java: a == null ? b : b == null ? a : a.compareTo(b) >= 0 ? a : b. Python: max(d for d in [a, b] if d is not None). Go: custom function with nil checks on time.Duration. EK9: left >? right — one operator handles all cases.

Keywords: coalescing, duration, period, >?, maximum, product, warranty, longer