PDB and mmCIF extraction

results = crabwurcs.extract_pdb_file("model.cif")
for result in results:
    print(result.glycan.to("wurcs"))
    for residue in result.residues:
        print(residue.node_index, residue.chain, residue.sequence_number)

Recognition uses, in order, the pinned wwPDB CCD component table, concrete registry names, GLYCAM residue decoding, and atom/coordinate-graph fallback for renamed components. Explicit connectivity records are authoritative; coordinate inference is conservative and does not invent inter-residue chains.

Attachment sites and insertion codes are retained. PDB/mmCIF writing, conformer generation, and coordinate optimization are intentionally outside the 0.3 scope.