Release 1.0a1 · hylang/hy

Removals

The core function name has been removed. Use unmangle or the name attribute of keyword objects instead.
deftag has been removed. Instead of (deftag foo …), say (defmacro "#foo" …).
#doc has been removed. Instead of #doc @, say (doc "#@").
__tags__ has been removed. Tag macros are now tracked in __macros__.

Lambda lists (function parameter lists) have been simplified. &optional is gone, &args is #*, &kwargs is #**, and &kwonly is *. Thus, [a &optional b [c 3] &rest args &kwargs kwargs] is now [a [b None] [c 3] #* args #** kwargs].
Hy models have been renamed to remove "Hy", and are no longer automatically brought into scope. Thus, HyList is now hy.models.List.
eval is no longer automatically brought into scope. Call it as hy.eval (or import it explicitly).
Calling a keyword object now does a string lookup, instead of a keyword-object lookup. Thus, (:key obj) is equivalent to (get obj (mangle (. :key name))).
To require a tag macro foo, instead of (require [module [foo]]), you must now say (require [module ["#foo"]]).
Mangling no longer converts leading hyphens to underscores, and unmangling no longer converts leading underscores to hyphens.
F-strings now have their own model type, and store their code parts as models instead of strings.

Python 3.10 is now supported.
Lambda lists now support positional-only arguments.
F-strings now support = syntax per Python.
with now supports unnamed context managers.
defmacro and require can now take macro names as string literals.
New standard macros do-n, list-n, and cfor.
The location of the REPL history file can now be set with the environment variable HY_HISTORY.
REPL initialization scripts are now supported with the envrionment variable HYSTARTUP.
The module hy.extra.reserved has a new function special.
New module hy.contrib.destructure for Clojure-style destructuring.
New module hy.contrib.slicing for multi-index sequence slicing.

Fixed the identifier J being incorrectly parsed as a complex number.
Attempts to assign to constants are now more reliably detected.
Fixed a bug where AST nodes from macro expansion did not properly receive source locations.
Fixed doc sometimes failing to find core macros.
doc now works with names that need mangling.
Fixed bugs with require of names that need mangling.
Fixed a compiler crash from trying to use .. as an operator.
Fixed namespace pollution caused by automatic imports of Hy builtins and macros.
require now works with relative imports and can name modules as members, as in (require [hy.contrib [walk]]).
Fixed error handling for illegal macro names.
Fixed hyc and hy2py not finding relative imports.
Fixed hy.contrib.walk.smacrolet requiring a module name.