This Python package contains utilities to read and write files in the Human-friendly Structured Data (HSD) format.

It is licensed under the BSD 2-clause license.

The HSD-format is very similar to both JSON and XML, but tries to minimize the effort for humans to read and write it. It ommits special characters as much as possible but (in contrast to YAML for example) is not indentation dependent.

It was developed originally developed as the input format for a scientific simulation tool (DFTB+), but is absolutely general. A typical input written in HSD would look like

driver {
  conjugate_gradients {
    moved_atoms = 1 2 "7:19"
    max_steps = 100
  }
}

hamiltonian {
  dftb {
    scc = yes
    scc_tolerance = 1e-10
    mixer {
      broyden {}
    }
    filling {
      fermi {
        temperature [kelvin] = 1e-8
      }
    }
    k_points_and_weights {
      supercell_folding = {
        2   0   0
        0   2   0
        0   0   2
        0.5 0.5 0.5
      }
    }
  }
}

Content in HSD format can be represented as JSON. Content in JSON format can be represented as HSD, provided it satisfies a restriction for arrays: Either all elements of an array must be objects or none of them. (This allows for a clear separation of structure and data and allows for the very simple input format.)

Content in HSD format can be represented as XML (DOM-tree). Content in XML can be converted to HSD, provided it satisfies the restriction that every child has either data (text) or further children, but never both of them. (Again, this ensures the simplicity of the input format.)