defined

Test whether an optional value is defined

Boolean defined(X?)

Tests whether the given optional value is defined, i.e., has a non-None value.

Parameters

  1. X?: optional value of any type.

Returns: false if the input value is None, otherwise true.

Example: is_defined.wdl

version 1.3

workflow is_defined {
  input {
    String? name
  }

  if (defined(name)) {
    call say_hello { name = select_first([name]) }
  }

  output {
    String? greeting = say_hello.greeting
  }
}

task say_hello {
  input {
    String name
  }

  command <<< printf "Hello ~{name}" >>>

  output {
    String greeting = read_string(stdout())
  }
}

Example input:

{
  "is_defined.name": "John"
}

Example output:

{
  "is_defined.greeting": "Hello John"
}