Interscript: Interoperable Script Conversion Systems for Python

Purpose

The official Python runtime for Interscript — deterministic transliteration over the interscript map corpus (300+ authority-backed systems: BGN/PCGN, ISO, UN, ALA-LC, ODNI, ICAO, DIN, and others).

This version (0.2.0) parses the .imp map DSL directly — no pre-compiled Python map modules or monorepo bootstrap required. Point it at the map corpus and go.

Maps that need vocalized input (undiacritized Arabic, nikud-less Hebrew, unsegmented Thai) dispatch to a secryst crystal through the optional phonological layer; see the phonological-layer documentation on our site.

Install

pip install interscript

Usage

import interscript

interscript.add_load_path(".../interscript/maps/maps")
interscript.transliterate("un-bul-Cyrl-Latn-1977", "нос Бяга БЯГА")
# -> "nos Byaga BYAGA"

API

• add_load_path(path) — register a directory containing .imp/.isc map files

• map_exist(name) — check whether a map is available

• map_list() — list all discoverable map names

• load_map(name) — parse and cache a map (returns an Engine)

• transliterate(name, text) — apply a map to text

Measured coverage (2026-08-20)

The engine passes maps' own embedded tests with the following scores; remaining gaps are documented in the test suite:

map	embedded tests	gap
un-bul-Cyrl-Latn-1977	98/98	none
un-ell-Grek-Latn-1987-ts	206/242	posix letter-class guards
bgnpcgn-prs-Arab-Latn-2007	loads, runs	proper-noun capitalization

Architecture

• parser.py — .imp DSL parser: metadata (incl. | block scalars), tests, dependency declarations, stages, parallel groups, sub expressions

• expr.py — expression layer: any("…") char classes, any("a".."z") ranges, any(["x","y"]) alternations, maybe("…"), space, boundary, line_start/line_end, + concatenation, before:/after: context guards

• engine.py — executor: parallel subs (longest-match-wins + word-aware casing), subst regex, run (dependency-aliased dotted targets), compose/decompose, downcase/upcase/titlecase

Sibling runtimes

• Ruby: gem install interscript (https://rubygems.org/gems/interscript)

• npm: npm install interscript (https://www.npmjs.com/package/interscript)

• This: pip install interscript

License

BSD-2-Clause. See LICENSE.adoc.