string.phi

{
  ⟦
    org ↦ ⟦
      eolang ↦ ⟦
        string ↦ ⟦
          as-bytes ↦ ∅,
          φ ↦ ξ.as-bytes,
          length ↦ ⟦
            λ ⤍ Lorg_eolang_string_length
          ⟧,
          slice ↦ ⟦
            λ ⤍ Lorg_eolang_string_slice,
            start ↦ ∅,
            len ↦ ∅
          ⟧
        ⟧,
        λ ⤍ Package
      ⟧,
      λ ⤍ Package
    ⟧
  ⟧
}