Version 29.1.1.0 of package Compat has just been released in GNU ELPA. You can now find it in M-x list-packages RET.
Compat describes itself as: ================================ Emacs Lisp Compatibility Library ================================ More at https://elpa.gnu.org/packages/compat.html ## Summary: To allow for the usage of Emacs functions and macros that are defined in newer versions of Emacs, compat.el provides definitions that are installed ONLY if necessary. If Compat is installed on a recent version of Emacs, all of the definitions are disabled at compile time, such that no negative performance impact is incurred. These reimplementations of functions and macros are at least subsets of the actual implementations. Be sure to read the documentation string to make sure. ## Recent NEWS: ━━━━━━━━━━━━━━━━━━━━━━━ COMPAT.EL - CHANGELOG ━━━━━━━━━━━━━━━━━━━━━━━ 1 Release of "Compat" Version 29.1.1.0 ══════════════════════════════════════ • The macros in `compat-macs.el' have been rewritten and simplified. The refactoring allows to further refine the criteria under which compatibility aliases, functions, macros and variables are installed. • Remove deprecated, prefixed compatibility functions. • Remove deprecated features `compat-help', `compat-font-lock' and `compat-24'. • Compat uses runtime checks (`boundp', `fboundp') to ensure that existing definitions are never overridden, when Compat is loaded on a newer Emacs than it was compiled on. • Compat compiles without byte compilation warnings on all supported Emacs versions. Warnings are treated as errors in the test suite. • Compat takes great care to remove unneeded definitions at compile time. On recent Emacs 29 the byte compiled files are empty and not loaded, such that Compat does not any cost to the Emacs process. • compat-26: Fix and test `image-property' setter. • compat-26: Fix and test `read-multiple-choice'. • compat-28: Fix and test `with-existing-directory'. • compat-28: Drop obsolete function `make-directory-autoloads'. • compat-29: Drop broken functions `string-pixel-width' and `buffer-text-pixel-size'. These functions had poor performance which lead to a downstream issue in the doom-modeline package. If a more efficient solution is possible, the function will be added back. • compat-29: Drop broken function `string-limit'. • compat-29: Drop broken macro `with-buffer-unmodified-if-unchanged', which relied on `buffer-hash' which does not exist on all supported Emacs versions. • compat-29: Add `pos-bol' and `pos-eol'. (Release <2023-01-07 Sat>) 2 Release of "Compat" Version 29.1.0.1 ══════════════════════════════════════ • Add multiple new tests for existing APIs. • Fix bugs in compatibility functions: `setq-local', `proper-list-p, prop-match-p', `file-name-concat', `replace-regexp-in-region', `replace-string-in-region'. • Add new Emacs 29 APIs. Some of them are still untested and may change. If you intend to use an Emacs 29 API please be careful and if possible contribute test cases. All untested functions are marked as `<UNTESTED>' in the Compat code. Over time tests for all functions will be added gradually. • Add the macros `compat-call' and `compat-function' to call compatibility functions. Since Compat avoids overwriting already existing functions, we must define separate compatibility function definitions for functions which changed their calling convention or behavior. These compatibility definitions can be looked up using `compat-function' and called with `compat-call'. For example `assoc' can be called with a `TESTFN' since Emacs 26. In Emacs 25 and older the calling convention was `(assoc KEY ALIST)'. In order to use the new calling convention you can use `(compat-call assoc KEY ALIST TESTFN)'. • Deprecate all `compat-*' prefixed functions. Instead use the aforementioned `compat-call' or `compat-function' macros. • Deprecate `compat-help.el' and `compat-font-lock.el.' • Development moved to GitHub. • BREAKING: Drop broken function `func-arity'. Using `func-arity' is generally discouraged and the function is hard to implement properly due to all the various function types. There it is unlikely that the function will get reintroduced in Compat. • BREAKING: Drop broken function `directory-files-recursively'. In case you need this function, a patch including tests is welcome. • BREAKING: Drop support for Emacs 24.3. Emacs 24.4 is required now. In case you still need Emacs 24.3 support, you can rely on Compat 28.1.2.2. (Release <2023-01-05 Thu>) 3 Release of "Compat" Version 28.1.2.2 ══════════════════════════════════════ This is a minor release that hopes to address . (Release <2022-08-25 Thu>) 4 Release of "Compat" Version 28.1.2.1 ══════════════════════════════════════ This is a minor release adding the following changes: • Add `derived-mode-p' defined in Emacs 27 • Add `provided-mode-derived-p' defined in Emacs 27 • Add `read-multiple-choice' defined in Emacs 26 … …