orthonym.assembly.identical_prefixes

Note

Internal API. Names and behaviour may change between releases.

Identical substituent prefixes of one scope are cited once, with a multiplying prefix.

“MULTIPLICATIVE PREFIXES ‘DI’, ‘TRI’, ETC. vs. ‘BIS’, ‘TRIS’, ETC.” (the Blue Book), (:7027): “Multiplicative prefixes… are the principal method for describing a

multiplicity of identical features of a structure in chemical names.” The locants of the group are cited together whatever their kind: “Lowest set of locants” (:3189), “Italic capital and lower-case letter locants are lower than Greek letter locants, which, in turn, are lower than numerals” (:3195), so the italic N is cited before the numerals, and (:3448) “multiplicative prefixes, if necessary, are then inserted and do not alter the alphabetical order already established”. Preferred names that cite them so: N,4-dimethyl-N-(3-methylphenyl)benzamide (PIN) (:32879), N,N,2-trimethyl-3-{...}propanamide (PIN) (:21624), N,N,N,1-tetramethylquinolin-1-ium- 3-aminium (PIN) (:42213).

A producer that cites the prefixes of the parent from several sources (the characteristic-group loop, the substituent walk, the N-substituents of an amine or an amide) used to put the sources side by side, so 2-methyl and N-methyl stood in one name and the parent read 2-(4-methoxyphenyl)-2-methyl-N-methylpropanamide. This module is the one place that combines them. Its input is either the parts of the prefixes (name and locants, shared_prefix_entries()) or the rendered prefixes (group_identical_prefixes()); a rendered prefix is read back into its parts and used only when the engine’s own writer of a multiplied component, naming_utils.multiplied_component, writes the very same text from them, so a prefix the reader does not fully understand is left as it was. Nothing is cut out of a finished name: the combined prefix is written again from its parts, and the set of (locant, substituent name) pairs of the input is the set of the output.

orthonym.assembly.identical_prefixes.cited_locants(locants)

locants as strings in the order they are cited in a group, the Blue Book: italic letters before numerals; prefix_locant_order_key).

orthonym.assembly.identical_prefixes.read_prefix(text)

text (‘N-methyl’, ‘2,3-dihydroxy’, ‘2-(4-methoxyphenyl)’) read into its locants and substituent; None unless multiplied_component writes exactly text from them. Two readings that disagree on the name are no reading.

orthonym.assembly.identical_prefixes.write_prefix(name, marked, locants)

The prefix that cites locants (as they are cited in a group) in front of the substituent name written with the marks marked.

orthonym.assembly.identical_prefixes.group_identical_prefixes(prefixes, *, sort=True)

The rendered prefixes of one parent with every substituent that is cited twice or more combined into one multiplied prefix, locants N-first (['2-methyl', 'N-methyl'] gives ['N,2-dimethyl']), in the order of when sort (the order the callers give a list of rendered prefixes, prefix_citation_sort_key with parent_locants).

A prefix the reader does not understand, one without locants, and a substituent whose two citations are the very same text (one group an earlier step listed twice, not two substituents) are left alone.

orthonym.assembly.identical_prefixes.shared_prefix_groups(ring_groups, n_groups, tag=<class 'str'>)

The substituents the ring and the nitrogens of an amine both carry, as multiplied prefixes.

ring_groups maps a substituent name to its locants on the ring and n_groups maps a name to the locants of the nitrogens that carry it (tag turns one of them into the text that is cited: ‘N’, or ‘N1’ from the superscript 1). A name in both is cited once, the italic N locants first (4-methylaniline with a methyl on the nitrogen, N,4-dimethylaniline); the grouping is composition_primitives.combine_identical_prefix_groups.

Returns (ring_groups, n_groups, entries): the two inputs without the shared names and entries, the (alphanumerical key, rendered prefix) pairs of the shared ones.

orthonym.assembly.identical_prefixes.shared_prefix_entries(ring_groups, n_names)

shared_prefix_groups() for an aniline, whose nitrogen carries the substituents n_names (one name per substituent, a name that occurs twice sits twice on the nitrogen). Returns (ring_groups, n_names, entries).

orthonym.assembly.identical_prefixes.split_prefix_zone(name)

(prefixes, parent) of a chain-amide name whose prefixes all cite locants: '2-{...}-3,3-dimethylbutanamide' gives (['2-{...}', '3,3-dimethyl'], 'butanamide'). None for a name of any other shape, or when a prefix is not one the engine’s writer of a multiplied component writes from its parts (read_prefix).

orthonym.assembly.identical_prefixes.merge_n_block_into_name(n_block, name)

name (a chain amide that cites prefixes of its own) with the N-substituents of n_block (‘N-methyl’, ‘N,N-diethyl’, ‘N-ethyl-N-methyl’) cited with them: where a substituent is cited in both, the group is one multiplied prefix, and the prefixes are in the order of (‘N-methyl’ in front of ‘3,3-dimethylbutanamide’ gives ‘N,3,3-trimethylbutanamide’). None when no substituent is shared, or when either text is not read with certainty; the caller then writes the block in front as before.

The result is audited: the (locant, substituent) pairs of the two texts are exactly those of the result.