Open Dylan 2026.2

This document describes the 2026.2 release of Open Dylan, released July, 2026. The highlights of the release are listed below. For complete details see the commit logs for this release.

Note

Some commit logs, for example for testworks and other libraries that are included in Open Dylan as git submodules, may be in other repositories.

Platform Support

  • On macOS, Apple Silicon (64-bit ArmV8 architecture) is now directly supported, making the use of Rosetta 2 no longer necessary.

Compiler

  • The compiler’s LLVM back-end now uses a set of function calling conventions that is compatible with a wider variety of platform ABIs, and which improves performance in certain situations (such as dispatching methods with keyword arguments).

  • Several phases of compilation, including Optimization, Emitting, and Linking, are now marginally faster.

  • The base-address keyword in LID and HDP project files, specifying a default load address for DLLs on Windows, has been obsoleted. The Base address project link option in the IDE has been removed, and the compiler will no longer attempt to assign a base address automatically when projects are saved.

IDE

  • The Help ‣ Contents and Index and Help ‣ Help on Selection menu items now open the https://opendylan.org web site in the default browser rather than starting an outdated HTML Help file.

Bundled Library Updates

Changes to libraries that are part of the opendylan repository.

Dylan

  • The maximum number of elements that can be stored in a <table> increased from 9562387 to 463830313.

Common-Dylan

  • A new byte-storage module provides low-level access to locally-allocated byte storage and object byte storage, consolidating various ad-hoc facilities that were previously spread throughout the codebase as described in Issue 1732.

System

  • rename-file now signals <file-exists-error> instead of <file-system-error> if the target file exists and if-exists: #"signal" (the default) is used.

  • On Unix platforms, the current-date function and the date-related file properties now return <date> objects providing microsecond precision. The current-timestamp function now properly reflects millisecond precision.

  • Several functions in the system library were previously implemented on Unix platforms using C library routines that used static storage, potentially compromising thread safety. These have been replaced with thread-safe alternatives.

Submoduled Library Updates

No submodule updates occurred in this release.

Contributors

We’d like to thank all the people that made contributions to this release and to surrounding libraries in the Dylan ecosystem….

  • Peter S. Housel

  • Carl Gay

  • Bruce Mitchener