Function nested

test/compute-engine/dictionary.test.ts:552–553

(leaf: Expression)

    const r = box(['At', dict, { str: 'depth' }] as any).evaluate();
    expect(r.isNaN === true || r.symbol === 'Missing').toBe(true);
  });

  it('leaves a non-string index unevaluated (string keys only)', () => {
    expect(box(['At', dict, 2] as any).evaluate().operator).toBe('At');
  });