orthonym.rules.greek_stereo_descriptors

Note

Internal API. Names and behaviour may change between releases.

Shared Greek stereodescriptor letters for natural-product nomenclature.

IUPAC 2013 (the Blue Book) writes the steroid ring-face and the carbohydrate anomeric configuration with the GREEK letters α, β, ξ — “The stereodescriptors ‘α’, ‘β’, and ‘ξ’ … are cited before the name of the fundamental parent structure”, “The symbols ‘α’, ‘β’, or ‘ξ’ … are placed immediately at the beginning of the name”. The prose uses the English words ‘alpha’/’beta’ only to name the letters; every emitted NAME uses the symbol (the Blue Book contains 5α 44×, α-D- 41×, β-D- 58×, and the spelled-out form inside a name 0×). OPSIN 2.9.0 parses the Greek symbol and the ASCII word to the identical structure, so routing every stereodescriptor emitter through these constants is a pure spelling-conformance change with no round-trip effect (mirrors the rules/lambda_convention.LAMBDA fix for λ).

This is the single source of truth: every steroid ring-face and sugar anomeric emitter imports ALPHA/BETA/XI from here, never a bare 'alpha'/'beta'.