segment {<segment-statement>} end

<segment-statement> :==

  name=<segid>
  --{Segid of newly created structure. default="    "}
  molecule name=<resname> number=<integer> end
  --{Create independent copies of named molecule.}
  chain {<segment-chain-statement>} end
  --{Setup sequence and connectivity between residues.}

  <segment-chain-statement> :==

    first <resname> tail=<reference>=<resname> end
    --{Define patch that will be applied to the first residue in a sequence.}
    last <resname> head=<reference>=<resname> end
    --{Define patch that will be applied to the last residue in a sequence.}
    link <resname>
      head=<reference>=<resname>
      tail=<reference>=<resname>
    end
    --{Define patch that will be applied between 2 residues in a sequence. 
       If no matching link is found, the chain is restarted.}
    separate-by-segid=<logical>
    --{When reading the sequence from a file, if a new segid is encountered
       restart the chain.}
    convert-chainid-to-segid=<logical>
    --{When reading a sequence from a file, take the segid from the chainid
       column if it is non-blank.}
    coordinates {<pdb-atom-record>} end
    --{Read sequence from PDB file.}
    sequence {<resname>} end
    --{Read this sequence.}