To handle Gromacs topologies, Gromologist implements a hierarchical representation of sections, subsections and entries. Sections represent high-level abstractions, such as individual molecule definitions, force field parameter sets or headers/footers. Subsections correspond to individual fragments of the topology file, delimited with the [ subsection name ] syntax, and directly handle most operations. Entries correspond to individual lines and provide a low-level access to all key features of the contents of a topology.