The plain ‘sequence’ expression.

  sequence do
    participant 'alpha'
    participant 'bravo'
    participant 'charly'
  end

using ‘let‘

‘let’ behaves like a sequence, but the children have their own variable scope.

  pdef = Ruote.process_definition do
    set 'v:var' => 'val'
    echo "out:${v:var}"
    let do
      set 'v:var' => 'val1'
      echo "in:${v:var}"
    end
    echo "out:${v:var}"
  end

# => out:val, in:val1, out:val

as a ‘case’ statement

  let do
    define 'published' do
      do_this
    end
    define 'reviewed' do
      do_that
    end
    subprocess '${case}'
  end

Subprocesses ‘published’ and ‘reviewed’ are bound in a local scope, that gets discarded when the let exits.