python-telegram-bot is a pure Python, asynchronous library that provides both low-level bindings to the Telegram Bot API and a high-level application framework for building Telegram bots. In production, it handles authentication, message sending/receiving, update processing, and bot lifecycle management. The library is used by developers to create bots that can respond to commands, messages, inline queries, callback queries, and other Telegram events, with support for payments, passports, polls, and more. The architecture is organized into three layers: the core `telegram` package containing data models for all Telegram API types (Chat, User, Message, etc.) with consistent serialization and equality semantics; the `telegram.ext` extension framework providing handlers (CommandHandler, MessageHandler, ConversationHandler), an Application class for orchestrating update processing, job queues, persistence, and rate limiting; and the `telegram.request` layer using httpx for async HTTP communication. The library uses async/await throughout and follows a handler-based event-driven pattern. Key entry points include `telegram.ext.Application` (built via `ApplicationBuilder`), `telegram.Bot` for direct API calls, and various handler classes. The primary data flow involves receiving updates from Telegram via polling or webhook, parsing them into `Update` objects, dispatching to registered handlers based on filters, and executing callback functions that can call Bot methods to respond. The library supports custom context types, persistent storage of bot/user/chat data, and scheduled jobs. External dependencies are minimal: `httpx` is the only required runtime dependency. Optional features require additional packages: `cryptography` for Telegram Passport, `APScheduler` for job queues, `cachetools` for callback data caching, `tornado` for webhook server, `aiolimiter` for rate limiting, and `pytz`/`zoneinfo` for timezone support. The library is extensively tested with both offline unit tests and online integration tests against the live Telegram API.
The progressr package provides a minimal, unifying API for reporting progress updates in R. It separates progress signaling (developer-controlled) from progress presentation (end-user controlled) using R's condition system. Developers create progressor functions to signal updates, while end users configure handlers to determine how progress is displayed (terminal, GUI, audio, notifications, or file-based). The architecture centers around a handler plugin system where `with_progress()` manages context and handler state. Key features include integration with parallel frameworks (future, furrr, plyr), Shiny compatibility via `withProgressShiny()`, and a global progression handler for R ≥ 4.0.0. The package emphasizes flexibility—handlers can be mixed and matched, progress reporting can be suppressed, and updates work seamlessly in iterative and parallel contexts. Software engineering rigor is evident through an extensive test suite (50+ test scripts in `inst/testme/`), continuous integration, semantic versioning, and comprehensive vignettes. The design avoids tight coupling—core components like `progressor()`, `with_progress()`, and `progress_aggregator()` are isolated and reusable. While dependencies on optional packages (cli, progress, beepr, etc.) introduce some maintenance complexity, the core remains stable and well-maintained with recent activity.