Unreleased

Breaking Changes

The py macro now dedents the input like pys.

Bug Fixes

Fixed an installation failure in some situations when version lookup fails.
Fixed traceback pointing in scripts with shebangs.

New Features

nonlocal and global can now be called with no arguments, in which case they're no-ops.

0.26.0 (released 2023-02-08)

Removals

Coloring error messages and Python representations for models is no longer supported. (Thus, Hy no longer depends on colorama.)

Breaking Changes

Various warts have been smoothed over in the syntax of ', `, ~, and ~@:
- Whitespace is now allowed after these syntactic elements. Thus one can apply ~ to a symbol whose name begins with "@".
- ` and ~ are no longer allowed in identifiers. (This was already the case for '.)
- The bitwise NOT operator ~ has been renamed to bnot.
Dotted identifiers like foo.bar and .sqrt now parse as expressions (like (. foo bar) and (. None sqrt)) instead of symbols. Some odd cases like foo. and foo..bar are now syntactically illegal.
New macro do-mac.
New macro pragma (although it doesn't do anything useful yet).
hy.cmdline.HyREPL is now hy.REPL.
Redundant scripts named hy3, hyc3, and hy2py3 are no longer installed. Use hy, hyc, and hy2py instead.

Bug Fixes

hy.REPL now restores the global values it changes (such as sys.ps1) after hy.REPL.run terminates.
hy.REPL no longer mixes up Hy's and Python's Readline histories when run inside Python's REPL.
Fixed hy.repr of non-compilable uses of sugared macros, such as (quote) and (quote 1 2).

New Features

Pyodide is now officially supported.
., .., etc. are now usable as ordinary symbols (with the remaining special rule that ... compiles to Ellipsis).
On Pythons ≥ 3.7, Hy modules can now be imported from ZIP archives in the same way as Python modules, via zipimport.
hy2py has a new command-line option --output.
hy2py can now operate recursively on a directory.

0.25.0 (released 2022-11-08)

Breaking Changes

dfor no longer requires brackets around its final arguments, so (dfor x (range 5) [x (* 2 x)]) is now (dfor x (range 5) x (* 2 x)).
except* (PEP 654) is now recognized in try, and a placeholder macro for except* has been added.

Bug Fixes

__file__ should now be set the same way as in Python.
\N{…} escape sequences are now recognized in f-strings.
Fixed a bug with python -O where assertions were still partly evaluated.
Fixed hy.repr of slice objects with non-integer arguments.

New Features

Python 3.11 is now supported.

Misc. Improvements

hyc now requires a command-line argument.
hyc prints each path it writes bytecode to, and its messages now go to standard error instead of standard output.

0.24.0 (released 2022-06-23)

This release is a direct successor to 1.0a4. We've returned to 0.* version numbers to work around the inflexibility of PyPI and pip regarding the default version to install. (We skipped some version numbers because this release is several major releases since 0.20.0.) Sorry for the mess.

Removals

Tag macros have been removed. Use reader macros instead, rewriting (defmacro "#foo" [arg] …) as (defreader foo (setv arg (.parse-one-form &reader)) …).
with-decorator and #@ have been removed in favor of decorator lists (see below).
Fraction literals have been removed. Use fractions.Fraction instead.
Unrecognized backslash escapes in string and byte literals are no longer allowed. (They've been deprecated in Python since 3.6.)
A bare # is no longer a legal symbol.
u is no longer allowed as a string prefix. (It had no effect, anyway.)
hy.read-str has been removed. Use hy.read, which now accepts strings, instead.

Other Breaking Changes

Tuples are now indicated with #( … ), as in #(1 2 3), instead of (, … ), as in (, 1 2 3).
Tuples have their own model type, hy.models.Tuple, instead of being represented as Expressions.
if now requires all three arguments. For the two-argument case (i.e., with no else-clause), when is a drop-in replacement.

cond has a new unbracketed syntax:

(cond [a b] [x y z])     ; Old
(cond  a b  x (do y z))  ; New

defmacro once again requires the macro name as a symbol, not a string literal.
Annotations are now indicated by #^ instead of ^.
annotate (but not #^) now takes the target first and the type second, as in (annotate x int).
The way f-strings are parsed has changed, such that unescaped double quotes are now allowed inside replacement fields.
Non-ASCII whitespace is no longer ignored during tokenization like ASCII whitespace.
The mangling rules have been refined to account for Python's treatment of distinct names as referring to the same variable if they're NFKC-equivalent. Very little real code should be affected.
hy.cmdline.run_repl has been replaced with hy.cmdline.HyREPL.run.

Bug Fixes

Fixed a crash when using keyword objects in match.
Fixed a scoping bug in comprehensions in let bodies.
Literal newlines (of all three styles) are now recognized properly in string and bytes literals.
defmacro no longer allows further arguments after #* args.
!= with model objects is now consistent with =.
Tracebacks from code parsed with hy.read now show source positions.
Elements of builtins such as help are no longer overridden until the REPL actually starts.
Readline is now imported only when necessary, to avoid triggering a CPython bug regarding the standard module curses (cpython#46927).
Module names supplied to hy -m are now mangled.
Hy now precompiles its own Hy code during installation.

New Features

Added user-defined reader macros, defined with defreader.
defn and defclass now allow a decorator list as their first argument.
... is now understood to refer to Ellipsis, as in Python.
Python reserved words are allowed once more as parameter names and keyword arguments. Hy includes a workaround for a CPython bug that prevents the generation of legal Python code for these cases (cpython#90678).
New macro export.
- Or you can set the variable _hy_export_macros to control what macros are collected by (require module *).
New macro delmacro.
New function hy.read_many.
New function hy.model_patterns.parse_if.
New function hy.model_patterns.in_tuple.
Added a command-line option -u (or --unbuffered) per CPython.
Tab-completion in the REPL now attempts to unmangle names.

1.0a4 (released 2022-01-09)

Removals

Python 3.6 is no longer supported.

Other Breaking Changes

import and require no longer need outer brackets. (import [foo [bar]]) is now (import foo [bar]) and (import [foo :as baz]) is now (import foo :as baz). To import all names from a module, use (import foo *).
Lots of objects (listed below) have been spun off to a new package called Hyrule, from which you can import or require them. Thus Hy now brings only the hy module and a limited set of core macros into scope automatically.
- Functions: butlast, coll?, constantly, dec, destructure, distinct, drop-last, end-sequence, flatten, inc, macroexpand-all, parse-args, pformat, postwalk, pp, pprint, prewalk, readable?, recursive?, rest, saferepr, walk
- Classes: PrettyPrinter, Sequence
- Macros: #%, #:, ->, ->>, ap-dotimes, ap-each, ap-each-while, ap-filter, ap-first, ap-if, ap-last, ap-map, ap-map-when, ap-reduce, ap-reject, as->, assoc, cfor, comment, defmacro!, defmacro/g!, defmain, defn+, defn/a+, defseq, dict=:, do-n, doto, fn+, fn/a+, ifp, let+, lif, list-n, loop, ncut, of, profile/calls, profile/cpu, seq, setv+, smacrolet, unless, with-gensyms
Functions that provide first-class Python operators, such as + in constructs like (reduce + xs), are no longer brought into scope automatically. Say (import hy.pyops *) to get them.
Hy scoping rules more closely follow Python scoping in certain edge cases.
let is now a core macro with somewhat different semantics. In particular, definition-like core macros (defn, defclass, import) now introduce new names that shadow corresponding let-bound names and persist outside the body of the let.
The constructors of String and FString now check that the input would be syntactically legal as a literal.
hy.extra.reserved has been renamed to hy.reserved.

Bug Fixes

In comprehension forms other than for, assignments (other than :setv and loop clauses) are now always visible in the surrounding scope.
match now only evaluates the subject once.
let will no longer re-evaluate the default arguments of a function it's used in.
hy.repr now properly formats bracket strings.
The repr and str of string models now include brackets if necessary.
When standard output can't accommodate Unicode, hy2py now crashes instead of emitting incorrect Python code.
Fixed a bug with self-requiring files on Windows.
Improved error messages for illegal uses of finally and else.

New Features

hy.repr now supports several more standard types.
The attribute access macro . now allows method calls. For example, (. x (f a)) is equivalent to (x.f a).
hy.as-model checks for self-references in its argument.
New function hy.model_patterns.keepsym.

1.0a3 (released 2021-07-09)

Bug Fixes

Fixed a dependency-management bug that prevented installation of Hy from a wheel on Pythons < 3.9.

1.0a2 (released 2021-07-07)

Removals

All reimplementations of functions in the package Toolz have been removed. Import these from Toolz (or CyToolz) instead. Beware that the Toolz functions are not all drop-in replacements for the old Hy functions; e.g., partition has a different order of parameters.
- complement, compose (formerly comp in Hy), drop, first, identity, interleave, interpose, iterate, juxt, last, merge-with, nth, partition, second, take-nth, take
All aliases of objects in Python's standard library have been removed. Import these objects explicitly instead.
- From itertools: accumulate, chain, combinations-with-replacement (formerly multicombinations in Hy), combinations, compress, count, cycle, dropwhile (formerly drop-while), filterfalse (formerly remove), groupby (formerly group-by), islice, permutations, product, repeat, starmap (formerly *map), takewhile (formerly take-while), tee, zip-longest
- From functools: reduce
- From fractions: Fraction (formerly fraction)
The following core predicate functions have been removed. Use isinstance etc. instead.
- empty?, even?, every?, float?, integer-char?, integer?, iterable?, iterator?, keyword?, list?, neg?, none?, numeric?, odd?, pos?, some, string?, symbol?, tuple?, zero?
Several other core functions and macros have been removed:
- keyword: Use (hy.models.Keyword (hy.unmangle …)) instead.
- repeatedly: Use toolz.iterate instead.
- if-not: Use (if (not …) …) instead.
- lif-not: Use (lif (not …) …) instead.
- macro-error: Use raise instead.
- calling-module: Now internal to Hy.
- calling-module-name: Now internal to Hy.

Other Breaking Changes

if no longer allows more than three arguments. Use cond instead.
cut with exactly two arguments (the object to be cut and the index) now works like Python slicing syntax and the slice function: (cut x n) gets the first n elements instead of everything after the first n.
In defn, the return-value annotation, if any, is now placed before the function name instead of after.
Python reserved words are no longer allowed as parameter names, nor as keywords in keyword function calls.
Hy model objects are no longer equal to ordinary Python values. For example, (!= 1 '1). You can promote values to models with hy.as-model before making such a check.
The following functions are now called as attributes of the hy module:
- hy.disassemble, hy.gensym, hy.macroexpand, hy.macroexpand-1, hy.repr (formerly hy.contrib.hy-repr.hy-repr), hy.repr-register (formerly hy.contrib.hy-repr.hy-repr-register)
cmp has been renamed to chainc.
defclass no longer automatically adds None to the end of __init__ method definitions.
All special forms have been replaced with macros. This won't affect most preexisting code, but it does mean that user-defined macros can now shadow names like setv.
hy.repr no longer uses the registered method of a supertype.
The constructors of Symbol and Keyword now check that the input would be syntactically legal.
Attempting to call a core macro not implemented on the current version of Python is now an error.
hy.extra.reserved.special has been replaced with hy.extra.reserved.macros.

New Features

hy-repr is now the default REPL output function.
The command python -m hy now works the same as hy.
New function hy.as-model.
New macro match (Python 3.10 only).
annotate is now a user-visible macro.

Bug Fixes

Fixed issues with newer prereleases of Python 3.10.
The REPL now properly displays SyntaxErrors.
Fixed a bug in pprint in which width was ignored.
Corrected repr and hy.repr for f-strings.
--spy and --repl-output-fn can now overwrite HYSTARTUP values.

1.0a1 (released 2021-04-12)

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__.

Other Breaking Changes

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.

New Features

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.

Bug Fixes

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.

Misc. Improvements

The library astor is no longer required on Pythons ≥ 3.9.

0.20.0 (released 2021-01-25)

Removals

Python 3.5 is no longer supported.

New Features

let macro now supports extended iterable unpacking syntax.
New contrib module pprint, a Hy equivalent of python.pprint.

Bug Fixes

Fixed a bug that made hy.eval from Python fail on require.
Fixed a bug that prevented pickling of keyword objects.
Fixed a compiler crash from setv with an odd number of arguments in defclass.

0.19.0 (released 2020-07-16)

Breaking Changes

parse-args is no longer implemented with eval; so e.g. you should now say :type int instead of :type 'int.

New Features

Python 3.9 is now supported.

Bug Fixes

Improved support for nesting anaphoric macros by only applying symbol replacement where absolutely necessary.
Quoted f-strings are no longer evaluated prematurely.
Fixed a regression in the production of error messages for empty expressions.
Fixed a scoping bug for code executed with hy -c.
Fixed a bug in the compilation of multiple requires.
Fixed various bugs in command-line option parsing.

0.18.0 (released 2020-02-02)

Removals

Python 2 is no longer supported.
Support for attribute lists in defclass has been removed. Use setv and defn instead.
Literal keywords are no longer parsed differently in calls to functions with certain names.
hy.contrib.multi has been removed. Use cond or the PyPI package multipledispatch instead.

Other Breaking Changes

HySequence is now a subclass of tuple instead of list. Thus, a HyList will never be equal to a list, and you can't use .append, .pop, etc. on a HyExpression or HyList.

New Features

Added special forms py to pys that allow Hy programs to include inline Python code.
Added a special form cmp for chained comparisons.
All augmented assignment operators (except %= and ^=) now allow more than two arguments.
Added support for function annotations (PEP 3107) and variable annotations (PEP 526).
Added a function parse-args as a wrapper for Python's argparse.

Bug Fixes

Statements in the second argument of assert are now executed.
Fixed a bug that caused the condition of a while to be compiled twice.
in and not-in now allow more than two arguments, as in Python.
hy2py can now handle format strings.
Fixed crashes from inaccessible history files.
Removed an accidental import from the internal Python module test.
Fixed a swarm of bugs in hy.extra.anaphoric.

Misc. Improvements

Replaced the dependency clint with colorama.

0.17.0 (released 2019-05-20)

Warning: Hy 0.17.x will be the last Hy versions to support Python 2, and we expect 0.17.0 to be the only release in this line. By the time 0.18.0 is released (in 2020, after CPython 2 has ceased being developed), Hy will only support Python 3.

Removals

Python 3.4 is no longer supported.

New Features

Python 3.8 is now supported.
Format strings with embedded Hy code (e.g., f"The sum is {(+ x y)}") are now supported, even on Pythons earlier than 3.6.
Added a special form setx to create Python 3.8 assignment expressions.
Added new core functions list? and tuple.
Gensyms now have a simpler format that's more concise when mangled (e.g., _hyx_XsemicolonXfooXvertical_lineX1235 is now _hyx_fooXUffffX1).

Bug Fixes

Fixed a crash caused by errors creating temporary files during bytecode compilation.

0.16.0 (released 2019-02-12)

Removals

Empty expressions (()) are no longer legal at the top level.

New Features

eval / hy_eval and hy_compile now accept an optional compiler argument that enables the use of an existing HyASTCompiler instance.
Keyword objects (not just literal keywords) can be called, as shorthand for (get obj :key), and they accept a default value as a second argument.
Minimal macro expansion namespacing has been implemented. As a result, external macros no longer have to require their own macro dependencies.
Macros and tags now reside in module-level __macros__ and __tags__ attributes.

Bug Fixes

Cleaned up syntax and compiler errors.
You can now call defmain with an empty lambda list.
require now compiles to Python AST.
Fixed circular requires.
Fixed module reloading.
Fixed circular imports.
Fixed errors from from __future__ import ... statements and missing Hy module docstrings caused by automatic importing of Hy builtins.
Fixed __main__ file execution.
Fixed bugs in the handling of unpacking forms in method calls and attribute access.
Fixed crashes on Windows when calling hy-repr on date and time objects.
Fixed a crash in mangle for some pathological inputs.
Fixed incorrect mangling of some characters at low code points.
Fixed a crash on certain versions of Python 2 due to changes in the standard module tokenize.

0.15.0 (released 2018-07-21)

Removals

Dotted lists, HyCons, cons, cons?, and list* have been removed. These were redundant with Python's built-in data structures and Hy's most common model types (HyExpression, HyList, etc.).
&key is no longer special in lambda lists. Use &optional instead.
Lambda lists can no longer unpack tuples.
ap-pipe and ap-compose have been removed. Use threading macros and comp instead.
for/a has been removed. Use (for [:async ...] ...) instead.
(except) is no longer allowed. Use (except []) instead.
(import [foo]) is no longer allowed. Use (import foo) instead.

Other Breaking Changes

HyExpression, HyDict, and HySet no longer inherit from HyList. This means you can no longer use alternative punctuation in place of square brackets in special forms (e.g. (fn (x) ...) instead of the standard (fn [x] ...)).
Mangling rules have been overhauled; now, mangled names are always legal Python identifiers.
_ and - are now equivalent, even as single-character names.
- The REPL history variable _ is now *1.
Non-shadow unary =, is, <, etc. now evaluate their argument instead of ignoring it.
list-comp, set-comp, dict-comp, and genexpr have been replaced by lfor, sfor, dfor, and gfor, respectively, which use a new syntax and have additional features. All Python comprehensions can now be written in Hy.
&-parameters in lambda lists must now appear in the same order that Python expects.
Literal keywords now evaluate to themselves, and HyKeyword no longer inherits from a Python string type
HySymbol no longer inherits from HyString.

New Features

Python 3.7 is now supported.
while and for are allowed to have empty bodies.
for supports the various new clause types offered by lfor.
defclass in Python 3 supports specifying metaclasses and other keyword arguments.
Added mangle and unmangle as core functions.
Added more REPL history variables: *2 and *3.
Added a REPL variable holding the last exception: *e.
Added a command-line option -E per CPython.
Added a new module hy.model_patterns.

Bug Fixes

hy2py should now output legal Python code equivalent to the input Hy code in all cases.
Fixed (return) so it can exit a Python 2 generator.
Fixed a case where -> and ->> duplicated an argument.
Fixed bugs that caused defclass to drop statements or crash.
Fixed a REPL crash caused by illegal backslash escapes.
NaN can no longer create an infinite loop during macro-expansion.
Fixed a bug that caused try to drop expressions.
The compiler now properly recognizes unquote-splice.
Trying to import a dotted name is now a syntax error, as in Python.
defmacro! now allows optional arguments.
Fixed handling of variables that are bound multiple times in a single let.

Misc. Improvements

hy-repr uses registered functions instead of methods.
hy-repr supports more standard types.
macroexpand-all will now expand macros introduced by a require in the body of a macro.

0.14.0 (released 2018-02-14)

Removals

Python 3.3 is no longer supported
def is gone; use setv instead
apply is gone; use the new #* and #** syntax instead
yield-from is no longer supported under Python 2
Periods are no longer allowed in keywords
Numeric literals can no longer begin with a comma or underscore
Literal Infs and NaNs must now be capitalized like that

Other Breaking Changes

Single-character "sharp macros" are now "tag macros", which can have longer names
xi from hy.extra.anaphoric is now a tag macro #%
eval is now a function instead of a special form

New Features

The compiler now automatically promotes values to Hy model objects as necessary, so you can write (eval `(+ 1 ~n)) instead of (eval `(+ 1 ~(HyInteger n)))
return has been implemented as a special form
Added a form of string literal called "bracket strings" delimited by #[FOO[ and ]FOO], where FOO is customizable
Added support for PEP 492 (async and await) with fn/a, defn/a, with/a, and for/a
Added Python-style unpacking operators #* and #** (e.g., (f #* args #** kwargs))
Added a macro comment
Added EDN #_ syntax to discard the next term
while loops may now contain an else clause, like for loops
#% works on any expression and has a new &kwargs parameter %**
Added a macro doc and a tag macro #doc
get is available as a function
~@ (unquote-splice) form now accepts any false value as empty

Bug Fixes

Relative imports (PEP 328) are now allowed
Numeric literals are no longer parsed as symbols when followed by a dot and a symbol
Hy now respects the environment variable PYTHONDONTWRITEBYTECODE
String literals should no longer be interpreted as special forms or macros
Tag macros (née sharp macros) whose names begin with ! are no longer mistaken for shebang lines
Fixed a bug where REPL history wasn't saved if you quit the REPL with (quit) or (exit)
exec now works under Python 2
No TypeError from multi-arity defn returning values evaluating to None
try forms are now possible in defmacro and deftag
Multiple expressions are now allowed in try
Fixed a crash when macroexpanding a macro with a named import
Fixed a crash when with suppresses an exception. with now returns None in this case.
Fixed a crash when --repl-output-fn raises an exception
Fixed a crash when HyTypeError was raised with objects that had no source position
assoc now evaluates its arguments only once each
Multiple expressions are now allowed in the else clause of a for loop
else clauses in for and while are recognized more reliably
Statements in the condition of a while loop are repeated properly
Argument destructuring no longer interferes with function docstrings
Nullary yield-from is now a syntax error
break and continue now raise an error when given arguments instead of silently ignoring them

Misc. Improvements

read, read_str, and eval are exposed and documented as top-level functions in the hy module
An experimental let macro has been added to hy.contrib.walk

0.13.1 (released 2017-11-03)

Bug Fixes

Changed setup.py to require astor 0.5, since 0.6 isn't backwards-compatible.

0.13.0 (released 2017-06-20)

Language Changes

Pythons 2.6, 3.0, 3.1, and 3.2 are no longer supported
let has been removed. Python's scoping rules do not make a proper implementation of it possible. Use setv instead.
lambda has been removed, but fn now does exactly what lambda did
defreader has been renamed to defsharp; what were previously called "reader macros", which were never true reader macros, are now called "sharp macros"
try now enforces the usual Python order for its elements (else must follow all excepts, and finally must come last). This is only a syntactic change; the elements were already run in Python order even when defined out of order.
try now requires an except or finally clause, as in Python
Importing or executing a Hy file automatically byte-compiles it, or loads a byte-compiled version if it exists and is up to date. This brings big speed boosts, even for one-liners, because Hy no longer needs to recompile its standard library for every startup.
Added bytestring literals, which create bytes objects under Python 3 and str objects under Python 2
Commas and underscores are allowed in numeric literals
Many more operators (e.g., **, //, not, in) can be used as first-class functions
The semantics of binary operators when applied to fewer or more than two arguments have been made more logical
(** a b c d) is now equivalent to (** a (** b (** c d))), not (** (** (** a b) c) d)
setv always returns None
When a try form executes an else clause, the return value for the try form is taken from else instead of the try body. For example, (try 1 (except [ValueError] 2) (else 3)) returns 3.
xor: If exactly one argument is true, return it
hy.core.reserved is now hy.extra.reserved
cond now supports single argument branches

Bug Fixes

All shadowed operators have the same arities as real operators
Shadowed comparison operators now use and instead of & for chained comparisons
partition no longer prematurely exhausts input iterators
read and read-str no longer raise an error when the input parses to a false value (e.g., the empty string)
A yield inside of a with statement will properly suppress implicit returns
setv no longer unnecessarily tries to get attributes
loop no longer replaces string literals equal to "recur"
The REPL now prints the correct value of do and try forms
Fixed a crash when tokenizing a single quote followed by whitespace

Misc. Improvements

New contrib module hy-repr
Added a command-line option --repl-output-fn

0.12.1 (released 2017-01-24)

Bug Fixes

Allow installation without Git

0.12.0 (released 2017-01-17)

This release brings some quite significant changes on the language and as a result very large portions of previously written Hy programs will require changes. At the same time, documentation and error messages were improved, hopefully making the language easier to use.

Language Changes

New syntax for let, with and defclass
defmacro will raise an error on &kwonly, &kwargs and &key arguments
Keyword argument labels to functions are required to be strings
slice replaced with cut to stop overloading the python built-in
removed redundant throw, catch, progn, defun, lisp-if, lisp-if-not, filterfalse, true, false and nil
global now takes multiple arguments
Nonlocal keyword (Python 3 only)
Set literals (#{1 2 3})
Keyword-only arguments (Python 3 only)
Setv can assign multiple variables at once
Empty form allowed for setv, del and cond
One-argument division, rationals and comparison operators (=, !=, <, >, <=, >=)
partition form for chunking collection to n-sized tuples
defn-alias and demacro-alias moved into hy.contrib.alias
None is returned instead of the last form in --init--
for and cond can take a multi-expression body
Hex and octal support for integer literals
Apply now mangles strings and keywords according to Hy mangling rules
Variadic if
defreader can use strings as macro names
as-> macro added
require syntax changed and now supports same features as import
defmulti changed to work with dispatching function
old defmulti renamed to defn
Lazy sequences added to contrib
defmacro! added for once-only evaluation for parameters
comp, constantly, complement and juxt added
keyword arguments allowed in method calls before the object

Bug Fixes

Better error when for doesn't have body
Better error detection with list comprehensions in Python 2.7
Setting value to callable will raise an error
defclass can have properties / methods with built-in names
Better error messages on invalid macro arguments
Better error messages with hy2py and hyc
Cmdline error to string conversion.
In python 3.3+, generator functions always return a value
&rest can be used after &optional

Misc. Improvements

Version information includes SHA1 of current commit
Improved Python 3.5 support
Allow specification of global table and module name for (eval ...)
General documentation improvements
Contrib.walk: Coerce non-list iterables into list form
Flow macros (case and switch)
ap-pipe and ap-compose macros
#@ reader macro for with-decorator
Type check eval parameters
and and or short-circuit
and and or accept zero or more arguments
read-str for tokenizing a line
botsbuildbots moved to contrib
Trailing bangs on symbols are mangled
xi forms (anonymous function literals)
if form optimizations in some cases
xor operator
Overhauled macros to allow macros to ref the Compiler
ap-if requires then branch
Parameters for numeric operations (inc, dec, odd?, even?, etc.) aren't type checked
import_file_to_globals added for use in emacs inferior lisp mode
hy.core.reserved added for querying reserved words
hy2py can use standard input instead of a file
alias, curry, flow and meth removed from contrib
contrib.anaphoric moved to hy.extra

Changes from 0.10.1

Language Changes

new keyword-argument call syntax
Function argument destructuring has been added.
Macro expansion inside of class definitions is now supported.
yield-from support for Python 2
with-decorator can now be applied to classes.
assert now accepts an optional assertion message.
Comparison operators can now be used with map, filter, and reduce.
new last function
new drop-last function
new lisp-if-not/lif-not macro
new symbol? function
butlast can now handle lazy sequences.
Python 3.2 support has been dropped.
Support for the @ matrix-multiplication operator (forthcoming in Python 3.5) has been added.

Bug Fixes

Nested decorators now work correctly.
Importing hy modules under Python >=3.3 has been fixed.
Some bugs involving macro unquoting have been fixed.
Misleading tracebacks when Hy programs raise IOError have been corrected.

Misc. Improvements

attribute completion in REPL
new -m command-line flag for running a module
new -i command-line flag for running a file
improved error messaging for attempted function definitions without argument lists
Macro expansion error messages are no longer truncated.
Error messaging when trying to bind to a non-list non-symbol in a let form has been improved.

Changes from 0.10.0

This release took some time (sorry, all my fault) but it's got a bunch of really nice features. We hope you enjoy hacking with Hy as much as we enjoy hacking on Hy.

In other news, we're Dockerized as an official library image! <https://registry.hub.docker.com/_/hylang/>

$ docker run -it --rm hylang hy 0.10.0 using CPython(default) 3.4.1 on Linux => ((lambda [] (print "Hello, World!"))) Hello, World!

Hy Society

Language Changes

Implement raise :from, Python 3 only.
defmain macro
name & keyword functions added to core
(read) added to core
shadow added to core
New functions interleave interpose zip_longest added to core
nth returns default value when out of bounds
merge-with added
doto macro added
keyword? to find out keywords
setv no longer allows "." in names

Internals

Builtins reimplemented in terms of python stdlib
gensyms (defmacro/g!) handles non-string types better

Tools

Added hy2py to installed scripts

Misc. Fixes

Symbols like true, false, none can't be assigned
Set sys.argv default to [''] like Python does
REPL displays the python version and platform at startup
Dockerfile added for https://registry.hub.docker.com/_/hylang/

Contrib changes

Fix ap-first and ap-last for failure conditions

Changes from 0.9.12

0.10.0 - the "oh man I'm late for PyCon" release

Thanks to theanalyst (Abhi) for getting the release notes together. You're the best! - Hy Society

Breaking Changes

We're calling this release 0.10 because we broke API. Sorry about that. We've removed kwapply in favor of using apply. Please be sure to upgrade all code to work with apply.

(apply function-call args kwargs) ; is the signature

Thanks

Major shoutout to Clinton Dreisbach for implementing loop/recur. As always, massive hugs to olasd for the constant reviews and for implementing HyCons cells. Thanks to @kenanb for redesigning the new Hy logo.

Many thanks to algernon for working on adderall, which helped push Hy further this cycle. Adderall is an implementation of miniKanren in Hy. If you're interested in using Adderall, check out hydiomatic, which prettifies Hy source using Adderall rules.

This release saw an increase of about 11 contributors for a point release, you guys rock!

-Hy Society

Language Changes

for revamped again (Last time, we hope!), this time using a saner itertools.product when nesting
lisp-if/lif added for the lisp-like everything is true if, giving seasoned lispers a better if check (0 is a value, etc)
Reader Macros are macros now!
yield-from is now a proper yield from on Python 3. It also now breaks on Python 2.x.
Added if-not macro
We finally have a lisp like cons cells
Generator expressions, set & dict comprehensions are now supported
(.) is a mini DSL for attribute access
macroexpand & macroexpand-1 added to core
disassemble added to core, which dumps the AST or equivalent python code
coll? added to core to check for a collection
identity function added to core

Misc. Fixes

Lots of doc fixes. Reorganization as well as better docs on Hy internals
Universal Wheel Support
Pygments > 1.6 supports Hy now. All codeblocks in docs have been changed from clojure to hy
Hy REPL supports invoking with --spy & -i options [reword]
first and rest are functions and not macros anymore
"clean" target added to Makefile
hy2py supports a bunch of commandline options to show AST, source etc.
Sub-object mangling: every identifier is split along the dots & mangled separately

Bug Fixes

Empty MacroExpansions work as expected
Python 3.4 port. Sorry this wasn't in a 3.4 release time, we forgot to do a release. Whoops.
eg/lxml/parse-tumblr.hy works with Python 3
hy2py works on Windows
Fixed unicode encoding issue in REPL during unicode exceptions
Fixed handling of comments at end of input (#382)

Contrib changes

Curry module added to contrib
Loop/recur module added which provides TCO at tail position
defmulti has been added - check out more in the docs -- thanks to Foxboron for this one!
Walk module for walking the Hy AST, features a macroexpand-all as well

Changes from Hy 0.9.11

tl;dr:

0.9.12 comes with some massive changes, We finally took the time to implement gensym, as well as a few other bits that help macro writing. Check the changelog for what exactly was added.

The biggest feature, Reader Macros, landed later in the cycle, but were big enough to warrant a release on its own. A huge thanks goes to Foxboron for implementing them and a massive hug goes out to olasd for providing ongoing reviews during the development.

Welcome to the new Hy contributors, Henrique Carvalho Alves, Kevin Zita and Kenan Bölükbaşı. Thanks for your work so far, folks!

Hope y'all enjoy the finest that 2013 has to offer, - Hy Society

Special thanks goes to Willyfrog, Foxboron and theanalyst for writing 0.9.12's NEWS. Thanks, y'all! (PT)

Language Changes

Translate foo? -> is_foo, for better Python interop. (PT)
Reader Macros!
Operators + and * now can work without arguments
Define kwapply as a macro
Added apply as a function
Instant symbol generation with gensym
Allow macros to return None
Add a method for casting into byte string or unicode depending on python version
flatten function added to language
Add a method for casting into byte string or unicode depending on python version
Added type coercing to the right integer for the platform

Misc. Fixes

Added information about core team members
Documentation fixed and extended
Add astor to install_requires to fix hy --spy failing on hy 0.9.11.
Convert stdout and stderr to UTF-8 properly in the run_cmd helper.
Update requirements.txt and setup.py to use rply upstream.
tryhy link added in documentation and README
Command line options documented
Adding support for coverage tests at coveralls.io
Added info about tox, so people can use it prior to a PR
Added the start of hacking rules
Halting Problem removed from example as it was nonfree
Fixed PyPI is now behind a CDN. The --use-mirrors option is deprecated.
Badges for pypi version and downloads.

Syntax Fixes

get allows multiple arguments

Bug Fixes

OSX: Fixes for readline Repl problem which caused HyREPL not allowing 'b'
Fix REPL completions on OSX
Make HyObject.replace more resilient to prevent compiler breakage.

Contrib changes

Anaphoric macros added to contrib
Modified eg/twisted to follow the newer hy syntax
Added (experimental) profile module

Changes from Hy 0.9.10

Many thanks to Guillermo Vayá (Willyfrog) for preparing this release's release notes. Major shout-out. (PT)

Misc. Fixes

Many many many documentation fixes
Change virtualenv name to be hy
Rewrite language.hy not to require hy.core.macros
Rewrite the bootstrap macros in hy
Cleanup the hy.macros module
Add comments to the functions and reorder them
Translation of meth from Python to Hy
PY3 should really check for Python >= 3
Add hy._compat module to unify all Python 2 and 3 compatibility codes.
Import future.print_statement in hy code
Coerce the contents of unquote-splice'd things to a list
Various setup.py enhancements.
PEP8 fixes
Use setuptools.find_packages()
Update PyPI classifiers
Update website URL
Install the argparse module in Python 2.6 and before
Delete the duplicate rply in install_requires. With the PyPI version, tests are failed.
Finally fixed access to hy.core.macros here. have to explicitly require them.

Language Changes

Slightly cleaner version of drop-while, could use yield-from when ready
Added many native core functions
Add zero? predicate to check if an object is zero
Macro if-python2 for compile-time choice between Python 2 and Python 3 code branches
Added new travis make target to skip flake8 on pypy but run it on all others
Add "spy mode" to REPL
Add CL handling to hyc
Add yield from via macro magic.
Add some machinery to avoid importing hy in setup.py
Add a rply-based parser and lexer
Allow quoting lambda list keywords.
Clarified rest / cdr, cleaned up require
Make with return the last expression from its branch
Fix yielding to not suck (#151)
Make assoc accept multiple values, also added an even/odd check for checkargs
Added ability to parse doc strings set in defclass declarations,
Provide bin scripts for both Windows and *nix
Removes setf in favor of setv

Changes from Hy 0.9.9

Stupid Fixes

I forgot to include hy.core.language in the sdist. (PT)

Changes from Hy 0.9.8

Syntax Fixes

Macros are now module-specific, and must be required when used. (KH)
Added a few more string escapes to the compiler (Thomas Ballinger)
Keywords are pseudo-callable again, to get the value out of a dict. (PT)
Empty expression is now the same as an empty vector. (Guillermo Vaya)

Language Changes

HyDicts (quoted dicts or internal HST repr) are now lists that compiled down to dicts by the Compiler later on. (ND)
Macros can be constants as well. (KH)
Add eval-when-compile and eval-and-compile (KH)
Add break and continue to Hy (Morten Linderud)
Core language libraries added. As example, I've included take and drop in this release. More to come (PT)
Importing a broken module's behavior now matches Python's more closely. (Morten Linderud)

Misc. Fixes

Ensure compiler errors are always "user friendly" (JD)
Hy REPL quitter repr adjusted to match Hy syntax (Morten Linderud)
Windows will no longer break due to missing readline (Ralph Moritz)

Changes from Hy 0.9.7

Syntax Fixes

Quasi-quoting now exists long with quoting. Macros will also not expand things in quotes.
kwapply now works with symbols as well as raw dicts. (ND)
Try / Except will now return properly again. (PT)
Bare-names sprinkled around the AST won't show up anymore (ND)

Language Changes

Added a new (require) form, to import macros for that module (PT)
Native macros exist and work now! (ND)
(fn) and (lambda) have been merged (ND)
New (defclass) builtin for class definitions (JD)
Add unquote-splicing (ND)

Errata

Paul was an idiot and marked the j-related bug as a JD fix, it was actually ND. My bad.

Changes from Hy 0.9.6

Syntax Fixes

UTF-8 encoded hy symbols are now hy_... rather than __hy_..., it's silly to prefex them as such. (PT)
j is no longer always interpreted as a complex number; we use it much more as a symbol. (ND)
(decorate-with) has been moved to (with-decorate) (JD)
New (unless) macro (JD)
New (when) macro (JD)
New (take) macro (@eigenhombre)
New (drop) macro (@eigenhombre)
import-from and import-as finally removed. (GN)
Allow bodyless functions (JD)
Allow variable without value in let declaration (JD)
new (global) builtin (@eal)
new lambda-list syntax for function defs, for var-arity, kwargs. (JK)

Language Changes

HUGE rewrite of the compiler. Massive thanks go to olasd and jd for making this happen. This solves just an insane number of bugs. (ND, PT, JD)
Eval no longer sucks with statements (ND)
New magic binary flags / mis fixes with the hy interpreter (WKG + @eigenhombre)

Changes from Hy 0.9.5

Syntax Fixes

.pyc generation routines now work on Python 3. (Vladimir Gorbunov)
Allow empty (do) forms (JD)
The else form is now supported in try statements. (JD)
Allow (raise), which, like Python, will re-raise the last Exception. (JD)
Strings, bools, symbols are now valid top-level entries. (Konrad Hinsen)
UTF-8 strings will no longer get punycode encoded. (ND)
bare (yield) is now valid. (PT)
(try) now supports the (finally) form. (JD)
Add in the missing operators and AugAssign operators. (JD)
(foreach) now supports the (else) form. (JD)

WARNING: WARNING: READ ME: READ ME:

From here on out, we will only support "future division" as part of hy. This is actually quite a pain for us, but it's going to be quite an amazing feature.

This also normalizes behavior from Py 2 --> Py 3.

Thank you so much, Konrad Hinsen.

Language Changes

(pass) has been removed from the language; it's a wart that comes from a need to create valid Python syntax without breaking the whitespace bits. (JD)
We've moved to a new import style, (import-from) and (import-as) will be removed before 1.0. (GN)
Prototypes for quoted forms (PT)
Prototypes for eval (PT)
Enhance tracebacks from language breakage coming from the compiler (JD)
The REPL no longer bails out if the internals break (Konrad Hinsen)
We now support float and complex numbers. (Konrad Hinsen)
Keywords (such as :foo) are now valid and loved. (GN)

Changes from Hy 0.9.4

Syntax Fixes

try now accepts else: (JD)

(try BODY (except [] BODY) (else BODY))

Changes from Hy 0.9.4

Syntax Fixes

Statements in the fn path early will not return anymore. (PT)
Added "not" as the inline "not" operator. It's advised to still use "not-in" or "is-not" rather than nesting. (JD)
let macro added (PT)
Added "~" as the "invert" operator. (JD)
catch now accepts a new format: (JD)

(catch [] BODY) (catch [Exception] BODY) (catch [e Exception] BODY) (catch [e [Exception1 Exception2]] BODY)
With's syntax was fixed to match the rest of the code. It's now: (PT)

(with [name context-managed-fn] BODY) (with [context-managed-fn] BODY)

Language Changes

Added and and or (GN)
Added the tail threading macro (->>) (PT)
UTF encoded symbols are allowed, but mangled. All Hy source is now presumed to be UTF-8. (JD + PT)
Better builtin signature checking (JD)
If hoisting (for things like printing the return of an if statement) have been added. '(print (if true true true))' (PT)

Documentation

Initial documentation added to the source tree. (PT)

Changes from Hy 0.9.3

Syntax Fixes

Nested (do) expressions no longer break Hy (PT)
progn is now a valid alias for do (PT)
defun is now a valid alias for defn (PT)
Added two new escapes for and " (PT)

Language Changes

Show a traceback when a compile-error bubbles up in the Hy REPL (PT)
setf / setv added, the behavior of def may change in the future.
print no longer breaks in Python 3.x (PT)
Added list-comp list comprehensions. (PT)
Function hoisting (for things like inline invocation of functions, e.g. '((fn [] (print "hi!")))' has been added. (PT)
while form added. (ND)

(while [CONDITIONAL] BODY)

Documentation

Initial docs added. (WKG + CW)

Changes from Hy 0.9.2

General Enhancements

hy.__main__ added, python -m hy will now allow a hy shim into existing Python scripts. (PT)

Language Changes

import-as added to allow for importing modules. (Amrut Joshi)
slice added to slice up arrays. (PT)
with-as added to allow for context managed bits. (PT)
% added to do Modulo. (PT)
Tuples added with the '(, foo bar)' syntax. (PT)
car / first added. (PT)
cdr / rest added. (PT)
hy --> .pyc compiler added. (PT)
Completer added for the REPL Readline autocompletion. (PT)
Merge the meth macros into hy.contrib. (PT)
Changed __repr__ to match Hy source conventions. (PT)
2.6 support restored. (PT)

Changes from Hy 0.9.1

General Enhancements

Hy REPL added. (PT)
Doc templates added. (PT)

Language Changes

Add pass (PT)
Add yield (PT)
Moved for to a macro, and move foreach to old for. (PT)
Add the threading macro (->). (PT)
Add "earmufs" in. (tenach)
Add comments in (PT)

Files

NEWS.rst

Latest commit

History

NEWS.rst

File metadata and controls

Unreleased

Breaking Changes

Bug Fixes

New Features

0.26.0 (released 2023-02-08)

Removals

Breaking Changes

Bug Fixes

New Features

0.25.0 (released 2022-11-08)

Breaking Changes

Bug Fixes

New Features

Misc. Improvements

0.24.0 (released 2022-06-23)

Removals

Other Breaking Changes

Bug Fixes

New Features

1.0a4 (released 2022-01-09)

Removals

Other Breaking Changes

Bug Fixes

New Features

1.0a3 (released 2021-07-09)

Bug Fixes

1.0a2 (released 2021-07-07)

Removals

Other Breaking Changes

New Features

Bug Fixes

1.0a1 (released 2021-04-12)

Removals

Other Breaking Changes

New Features

Bug Fixes

Misc. Improvements

0.20.0 (released 2021-01-25)

Removals

New Features

Bug Fixes

0.19.0 (released 2020-07-16)

Breaking Changes

New Features

Bug Fixes

0.18.0 (released 2020-02-02)

Removals

Other Breaking Changes

New Features

Bug Fixes

Misc. Improvements

0.17.0 (released 2019-05-20)

Removals

New Features

Bug Fixes

0.16.0 (released 2019-02-12)

Removals

New Features

Bug Fixes

0.15.0 (released 2018-07-21)

Removals

Other Breaking Changes

New Features

Bug Fixes

Misc. Improvements

0.14.0 (released 2018-02-14)

Removals

Other Breaking Changes

New Features

Bug Fixes

Misc. Improvements

0.13.1 (released 2017-11-03)

Bug Fixes

0.13.0 (released 2017-06-20)