changelog.md

Summary of user-visible changes

Changes are marked in bold which could result in backwards-incompatibility.

Note that since 0.3.0, no deprecations have actually resulted in removals. They are advisory only and we have no plans to break the deprecated forms.

1.6.0 / ???

New Features

• Precompile built-in macros, improving startup time significantly.
• Accept :global-mangle false in compiler opts to disable global mangling.
• Macro sandbox can now read (but not write) files.

Bug Fixes

• Work around string formatting bug in Fengari.
• Use options.warn when provided in the parser.

1.5.1 / 2024-08-24

Bug Fixes

• ,doc/fennel.doc: Don't mutate :fnl/arglist directly when showing callable form
• (set (. tgt k1 ...) v) now works on known globals and $, $1 ... $9 in hashfns
• Macro quote expansion no longer breaks when sym, list or sequence is shadowed
• Bring fennel.traceback behavior closer to Lua's traceback by not modifying non-string and non-nil values.
• Avoid losing precision when compiling large numbers on LuaJIT.
• Add syntax for representing infinity and NaN values.

1.5.0 / 2024-06-23

New Features

• Macro pick-values is now a special, allowing it to emit better Lua output.
• Add fennel.getinfo as source-map-aware equivalent of debug.getinfo.
• Optimize allocation away when destructuring tables to tables.
• Allow & and &as in the same destructure clause.
• More consistent module-not-found warnings for --require-as-include.
• Improve compiler output for and/or forms with potential side-effects.
• Allow locals in places where they make sense rather than mid-expression.
• Accept --keywords option to add to the list of built-in Lua keywords.
• REPL completion now works on partial REPL commands: e.g. ,complete ,d -> ,doc.
• Tables in the REPL default to printing with limited depth.
• View settings in REPL can be changed: (set ___repl___.view-opts.depth 100).
• Support dynamic field names in (set (. tbl field) val).
• The fennel.compile function now accepts an AST, iterator, or file.
• Catch typos when a space is missing after a string.

Bug Fixes

• (pick-values 0 (side-effects)) now correctly preserves side effects
• Don't non-nil assert on _foo arguments in lambda.
• Propagate compile options into ,compile repl command.
• IIFEs emitted by and/or inside (fn [...]) now propagate varargs.
• macrodebug on cyclic macro expansions now serialize to valid code (no @1, ..)

1.4.2 / 2024-02-23

Bug Fixes

• Fix a bug where (tail! (f x)) could sometimes compile to return return f(x)
• Make tail! ensure its target is not a special form call like (tail! (or x (f)))
• Fix broken man page installation on make install

1.4.1 / 2024-02-19

This was the last release that provided Linux arm32 binaries.

New Features

• Iterators accept locals wrapped in parens like all other multi-value bindings.
• fennel.repl is now a callable table, allowing the default (fennel.repl) options to be customized by setting option fields on the table itself. This accidentally caused incompatibility with coroutine.create.

Bug Fixes

• Fix a bug with metadata tables in lambda being ignored.
• Fix identity value for band operator.
• Fix a bug in icollect with &into and multiple values.
• assert-repl, as a drop-in replacement for assert, no longer takes an opts param
• Fix a bug where (. (a-macro) k) bypassed protections against invalid Lua output

Changes and Removals

• Deprecate the __fennelrest destructuring metamethod.

1.4.0 / 2023-12-01

Bug Fixes

• Prevent metadata from being accessible in compiler sandbox.

New Forms

• Add tail! which asserts that the argument is called in tail position.
• Add assert-repl to make an assertion which opens a repl when it fails.

New Features

• Add --assert-as-repl flag to replace assert calls with assert-repl.
• Allow you to return a value from the repl with ,return FORM command.
• Save previous REPL values in *1, *2, and *3 locals.
• Make repl prompt change when repl sessions get nested.

1.3.1 / 2023-07-07

New Features

• fennel.runtime-version will return version information as a table if given optional argument
• Expose REPL's methods in the ___repl___ table, allowing method redefinition at runtime.
• Allow following docstring with a metadata table syntax.
• Return whole metadata table when metadata.get is called without a key.
• Add :byte-escape option to fennel.view for overriding default char escapes
• Generate man pages for fennel-api(3), fennel-reference(5), and fennel-tutorial(7) from their respective documentation.

Note for packagers: The man page fennel.1 has been moved to man/man1/fennel.1 along with the new generated man pages. For build scripts that copy files manually in lieu of make install, this may require an update.

Bug Fixes

• Fix a bug where operator compiler output had incorrect precedence with 3+ args
• Fix a bug where the comment special would fail on forms containing "]]"
• Fix a bug where tables like {:true 1 true 2} emit with unstable key order
• Fix a bug where table literals mutated by a macro emit with unstable key order when AOT-compiled in Lua > 5.2
• Fix a bug where very long individual lines in the repl would be truncated
• Fix an edge case where {:__metatable true} (as in pandoc-lua) breaks fennel.view
• Fix a 1.3.0 bug where macros only accepts table literals, not table-returning exprs
• Fix a bug where metadata tables with different arglists break lambdas
• Fix a bug with detecting cycles for tables that have custom __pairs metamethod in fennel.view
• Fix a bug where vararg couldn't be the only thing in a hashfn

1.3.0 / 2023-02-13

New Forms

• Add case which does pattern matching without pinning existing locals
• Add case-try which works like match-try without pinning locals
• Add faccumulate macro as range analog to accumulate

New Features

• Reduced compiler memory footprint
• Omit escape codes highlighting errors when NO_COLOR env var is set
• Support & for rest args in function arglists for consistency with let
• Add error-pinpoint option to support custom error highlighting
• The fn special now allows arbitrary compiler metadata keys via the metadata table syntax
• Options in fennel.view can be altered for the next invocation of the pretty-printer by setting them to {:once val} or {:once val :after other-val}. See fennel.view docstring for more info

Bug Fixes

• Fix a bug where readline repl history would be saved to the wrong file
• Fix a bug where set did not catch unknown locals when setting table fields
• Add a workaround for a bug around ctrl-d in readline

1.2.1 / 2022-10-15

New Features

• Add fennel.install function to the API for adding the searcher
• Add missing table? predicate to fennel API to go with list?, sym?, etc

Bug Fixes

• Skip autogenerated locals in repl locals saving to avoid exceeding local limit
• Ensure (values) consistently evaluates to zero values
• Fix bug preventing new macros from shadowing other macros
• Ensure macros use stable pairs table traversal for reproducible builds

1.2.0 / 2022-08-27

New Forms

• Add fcollect macro for range "comprehension"

New Features

• Make include splice modules in where they're used instead of at the top
• Add ast-source function to API to get file/line info from AST nodes
• Show errors using terminal control codes instead of arrow indicator
• Parser now includes column information (byte-based) in AST nodes
• For greater consistency, add &into/&until to certain looping constructs

Bug Fixes

• Duplicate table keys no longer crash the compiler
• Don't print stack trace for compiler errors in built-in macros
• Fix an issue with native modules in --compile-binary
• Improve argument handling so unused arguments get passed on to script
• Fix a bug where macros modifying table literals would emit incorrect output
• Fix a bug in the REPL where parser errors display the error message as nil
• Fix a bug when nil were emitted by unquote in a macro, and the macro was not compiled correctly because the resulting list length was calculated incorrectly
• Fix a REPL bug where ,doc m.foo did not resolve multisym to macro for macro modules loaded as macro table via (import-macros m :my.macro.module)

1.1.0 / 2022-04-09

New Forms

• Add match-try macro for chained pattern matching for steps which might fail

New Features

• The fennel.parser function now accepts a string in addition to an iterator
• The accumulate macro can now accumulate over multiple values
• The fn special now accepts a metadata table in place of a docstring
• The ,reload mod repl command can now reload macro modules

Bug Fixes

• Fix an issue where built-in macros would modify their AST arguments
• Fix a bug where --skip-include would mistakenly emit a warning
• Remove hex string escapes to preserve PUC Lua 5.1 compatibility
• Prevent errors resolving the target of certain repl commands from crashing
• Fix a bug where disabling the compiler sandbox broke module require scope
• Fix a bug where certain specials wouldn't short-circuit in and/or
• Fix a bug where symbols bound to nil did not show up in REPL completion

Changes and Removals

• Deprecate the granulate and string-stream functions in the API
• Deprecate the global form in favor of using the _G table

1.0.0 / 2021-11-14

New Features

• Allow collect to take two direct body arguments instead of requiring values
• Support --rename-native-module when compiling binaries
• Add :into clause to collect and icollect
• Add Macro guide
• Improve consistency of table key ordering in compiled output
• Apply strict globals checking in the repl by default
• Allow strict globals checking to be disabled with --globals "*"
• Emit warning when --require-as-include fails to find a module to include
• Support --add-macro-path for configuring macro path similarly to fennel module paths
• Support __fennelrest metamethod for changing & destructuring behavior

Bug Fixes

• Apply nil checks to & destructuring inside match
• Fix a bug where relative require didn't work with import-macros
• The fennel.view function no longer outputs invalid UTF-8 when given invalid input
• Fix a bug where macro modules did not get compiler options propagated
• Fix a bug where -?> and -?>> checked for false values, not just nil
• Fix a bug where let locals escaped their scope at the top level of the repl

Changes and Removals

• Remove fennelview.lua from the repo as it is part of the main API now
• Remove doc special form; replace with ,doc repl command
• Compiler plugins will warn when run on a version they do not support
• Backslash followed by a literal newline in a string is now parsed as newline
• Improve performance of icollect by avoiding unnecessary length checks
• Enforce compiler sandbox by default instead of warning
• Disallow & in identifiers
• Implicit else branches in if are treated as nil, not zero values
• Require explicit _ for else clause in match

0.10.0 / 2021-08-07

It's Fennel's 5th birthday! We've got the new accumulate macro for reducing over tables, plus a couple new repl commands and more flexibility when using include.

New Forms

• Add accumulate macro for reduce operations

New Features

• Add --skip-include option to prevent modules from being included in output
• Add ,apropos pattern and ,apropos-doc pattern repl commands
• Add ,complete foo repl command
• Add fennel.syntax function describing built-ins
• Add -c alias for --compile in command line arguments
• Allow using expressions in include and make --require-as-include resolve module names dynamically. See the require section in the reference
• Support repl completion on methods
• Make macro tables shadow runtime tables more consistently
• Keep gaps when printing sparse sequences; see max-sparse-gap option in fennel.view

Bug Fixes

• Fix a bug with strict global checking in macro modules

Changes and Removals

• Deprecate pick-args macro
• Add separate fennel.macro-path for searching for macro modules and FENNEL_MACRO_PATH environment variable

0.9.2 / 2021-05-02

This release mostly contains small bug fixes.

New Features

• Add Fennel for Clojure Users guide
• Never treat _ENV as an unknown global
• Improve behavior of ?. when used directly on nil

Bug Fixes

• Fix multi-value destructuring in pattern matches that use where
• Fix a bug around disambiguating parens in method calls
• Fix a bug where line number correlation was thrown off in macros
• Fix a bug where --use-bit-lib was not propagating to the REPL

0.9.1 / 2021-04-10

This release contains one small bug fix.

Bug Fixes

• Fix a bug in compiled output for statement separators in LuaJIT

0.9.0 / 2021-04-08

The biggest change in this release is the addition of the :until clause in all iteration forms to end iteration early.

New Forms

• Add nil-safe table access operator ?.
• Add support for guards using where/or clauses in match

New Features

• Add --use-bit-lib flag to allow bitwise operations to work in LuaJIT
• Add macro-searchers table for finding macros similarly to package.searchers
• Support &as inside pattern matches
• Include stack trace for errors during macroexpansion
• The sym function in compile scope now takes a source table second argument
• Support :until clauses for early termination in all loops
• Support :escape-newlines? and :prefer-colon? options in fennel.view
• Allow symbols to compare as equal in macros based on name

Bug Fixes

• Fix a bug where newlines were emitted with backslashes in fennel.view
• Fix a bug in the compiler sandbox where requiring had the wrong scope

0.8.1 / 2021-02-02

This release mostly contains small bug fixes.

Bug Fixes

• Fix compiler sandboxing to copy standard tables and protect metatables
• Fix an issue where loading nested copies of Fennel would fail
• Fix a bug where sparse tables were displayed incorrectly in fennel view
• Fix a bug where certain numbers would be emitted incorrectly

0.8.0 / 2021-01-18

The highlight of this release is the table comprehension macros which take the place of map in other lisps. The &as clause in destructuring now allows you to access the original table even as you destructure it into its fields. The fennel.view serializer has been completely rewritten to improve indentation.

New Forms

• Add table "comprehension" macros (collect/icollect)

New Features

• Allow the parser to optionally include comments in the parsed AST
• The fennelview module is now incorporated into the compiler as fennel.view
• Fully rewrite fennel.view for better indentation handling
• Improve printing of destructured args in function arglist in doc
• Allow plugins to provide repl commands
• Label auto-generated locals in Lua output for improved readability
• Add whole-table destructuring with &as
• Provide ... arguments consistently with Lua when requiring modules
• fennelview: respect presence of __fennelview metamethod on userdata metatables

Bug Fixes

• Fix the behavior of ... inside eval-compiler
• Fix a bug where decimal numbers would be emitted with commas in some locales
• Fix a bug where import-macros would not respect certain compiler options
• Fix a bug where shebang caused incorrect sourcemapped row/col in stacktraces

Changes and Removals

• Warn when using the & character in identifiers; will be disallowed later
• Numbers using underscores for readability may not begin with an underscore

0.7.0 / 2020-11-03

This release adds support for reloading modules in the repl, making interactive development more streamlined.

New Features

• Improve printing of multiple return values in the repl
• Add repl commands including ,reload; see ,help for a full list

Bug Fixes

• Fix several bugs in the linter
• Fix a bug where --no-compiler-sandbox did not apply in import-macros
• Fix a bug where compiler sandboxing makes macrodebug fail to print correctly
• Fix a bug in : when used with methods that are not valid Lua names

0.6.0 / 2020-09-03

This release introduces the plugin system as well as starting to sandbox the compiler environment for safer code loading. Nothing is blocked yet, but it emits warnings when macros use functionality that is not considered safe; future versions will prevent this.

New Features

• Add compiler plugin system
• Add --lua CLI flag for specifying a custom Lua command/executable
• Expose list? and sym? in compiler API
• Sandbox compiler environment and emit a warning when it leaks

Bug Fixes

• Fix a bug where repls would fail when provided with an overridden env
• Fix a bug where long arglists could get jumbled
• Fix a bug where method calls would early-evaluate their receiver
• Fix a bug where multi-arity comparisons would early-evaluate their arguments

Changes and Removals

• Change table reference notation in fennelview to use @

0.5.0 / 2020-08-08

This release features a version of the Fennel compiler that is self-hosted and written entirely in Fennel!

New Features

• The fennel.friend module is now incorporated into the compiler, not separate

Bug Fixes

• Fix a bug where lambdas with no body would return true instead of nil
• Fix a bug where global mangling would break when used with an environment
• Fix a bug where globals tracking would lose track of allowed list
• Fix a bug where top-level expressions in include would get skipped

0.4.3 / 2023-02-12

This release backports all the features from the 1.3.0 release to the pre-self-hosted version of the compiler for bootstrapping purposes. There should be no reason to use this, other than to build a newer version.

New Forms

• Backport new match rewrite as well as case, case-try, and match-try
• Backport accumulate, faccumulate, and fcollect macros
• Backport ?. macro
• Backport collect and icollect macros
• Backport :until support in each and other loops.
• Backport &as destructuring

Bug fixes

• Backport a bug fix where comparison operators could double-eval args
• Backport a bug fix where expressions would not get evaluated
• Backport a bug fix where long arglists would get reordered

0.4.2 / 2020-07-11

This release mostly includes small bug fixes but also adds the with-open macro for automating closing file handles, etc.

New Features

• Support varargs in hashfn with $...
• Add with-open macro for auto-closing file handles
• Add --native-module and --native-library to --compile-binary command
• Make autogensym symbols omit "#" when appending unique suffix
• Add fennel.searchModule function to module API

Bug Fixes

• Fix a bug where multiple include calls would splice locals incorrectly
• Fix a bug where autogensyms (using #) couldn't be used as multisyms
• Fix a bug causing include to ignore compiler options
• Fix a bug causing the repl to fail when $HOME env var was not set

0.4.1 / 2020-05-25

This release mostly includes small bug fixes, but also introduces a very experimental command for compiling standalone executables.

New Features

• Experimental --compile-binary command
• Support shebang in all contexts, not just dofile
• Pinpoint source in compile errors even when loading from a string

Bug Fixes

• Fix a bug where included modules could get included twice
• Fix a 0.4.0 bug where macros can't expand to string/boolean/number primitives
• Fix a bug in macros returning forms of a different length from their input

0.4.0 / 2020-05-12

This release adds support for Lua 5.3's bitwise operators as well as a new way of importing macro modules. It also adds pick-values and pick-args for a little more flexibility around function args and return values. The compiler now tries to emit friendlier errors that suggest fixes for problems.

New Forms

• Add import-macros for more flexible macro module loading
• Add bit-wise operators rshift, lshift, bor, band, bnot, and bxor
• Add new macroexpand helper to expand macro forms during compilation
• Add macrodebug utility macro for printing expanded macro forms in REPL
• Add pick-values and pick-args macros

New Features

• Ensure deterministic compiler output
• Friendlier compiler/parse error messages with suggestions
• Omit compiler internal stack traces by default unless FENNEL_DEBUG=trace
• Add support for __fennelview metamethod for custom serialization

Bug Fixes

• Fix a bug where dofile would report the wrong filename
• Fix bug causing failing include of Lua modules that lack a trailing newline

0.3.2 / 2020-01-14

This release mostly contains small bug fixes.

Bug Fixes

• Fix a bug where include could not be nested without repetition
• Fix a bug where globals checking would mistakenly flag locals
• Fix a bug that would cause incorrect filenames in error messages
• Fix a bug causing else to emit twice in some contexts

Changes and Removals

• Disallow naming a local the same as global in some contexts

0.3.1 / 2019-12-17

This release mostly contains small bug fixes.

New Features

• Look for init file for repl in XDG config dirs as well as ~/.fennelrc
• Add support for --load FILE argument to command-line launcher
• Make repl completion descend into nested table fields

Bug Fixes

• Fix each to work with raw iterator values
• Fix repl completer to correctly handle symbol mangling

0.3.0 / 2019-09-22

This release introduces docstrings as well as several new features to the macro system and some breaking changes; the most significant being the new unquote syntax and the requirement of auto-gensym for identifiers in backtick.

New Forms

• Add include special form to selectively inline modules in compiled output
• Add support for docstrings and doc for displaying them in repl
• Alias # special with length
• Add hashfn and # reader macro for shorthand functions like #(+ $1 $2)
• Add macro to make defining a single macro easier
• Add (comment) special which emits a Lua comment in the generated source

New Features

• Support :detect-cycles? false in fennelview to turn off "#<table 1>" output
• Support x# syntax for auto-gensym inside backtick
• Support :one-line output in fennelview
• Add --require-as-include to inline required modules in compiled output
• Add --eval argument to command-line launcher
• Add environment variable FENNEL_PATH to path
• Add support for guard clauses with ? in pattern matching
• Support completion in repl when readline.lua is available
• Add --globals and --globals-only options to launcher script
• Allow lua-style method calls like (foo:bar baz); disallow : in symbols

Bug Fixes

• Fix a bug where errors would show incorrect line numbers
• Fix a bug in lambda argument checks when using destructuring
• Fix a few bugs in match

Changes and Removals

• Disallow non-gensym identifiers in backtick/macros
• Remove undocumented support for single-quoted strings
• Remove luaexpr and luastatement for a single lua special
• Replace @ (unquote) with ,; comma is no longer whitespace
• Disallow ~ in symbols other than ~=

0.2.1 / 2019-01-22

This release mostly contains small bug fixes.

New Forms

• Add not= as an alias for ~=

New Features

• Improve error reporting for mismatched delimiters

Bug Fixes

• Fix a bug with in-scope? which caused match outer unification to fail
• Fix a bug with variadic ~= comparisons

0.2.0 / 2019-01-17

The second minor release introduces backtick, making macro authoring much more streamlined. Macros may now be defined in the same file, and pattern matching is added.

New Forms

• Add -?> and -?>> macros
• Add match macro for pattern matching
• Allow macros to be defined inline with macros

New Features

• Add support for quoting with backtick and unquoting with @ (later changed to ,)
• Prevent creation of bindings that collide with special forms and macros
• Make parens around steps optional in arrow macros for single-arg calls
• Add --add-package-path and --add-fennel-path to launcher script
• Support key/value tables when destructuring
• Add optional GNU readline support for repl

Bug Fixes

• Fix a bug where runtime errors were not reported by launcher correctly
• Allow repl to recover gracefully from parse errors

0.1.1 / 2018-12-05

This release contains a few small bug fixes.

Bug Fixes

• Fix luarocks packaging so repl includes fennelview
• Fix bug in the repl where locals-saving would fail for certain input
• Fix launcher to write errors to stderr, not stdout

0.1.0 / 2018-11-29

The first real release sees the addition of several "creature comfort" improvements such as comments, iterator support, line number tracking, accidental global protection, pretty printing, and repl locals. It also introduces the name "Fennel".

New Forms

• Add -> and ->> macros
• Add var; disallow regular locals from being set
• Add global; refuse to set globals without it
• Add require-macros
• Add // for integer division on Lua 5.3+
• Add fennel.dofile and fennel.searcher for require support
• Add partial
• Add local
• Add doto macro
• Add : for method calls
• Add each
• Add lambda/λ for nil-argument-checked functions
• Add when

New Features

• Add comments
• Add fennelview pretty-printer
• Save locals in between chunks in the repl
• Allow destructuring in more places
• Support newlines in strings
• Prevent typos from accidentally referring to unknown globals
• Improve readability of compiler output
• Make comparison operators variadic
• Support destructuring "rest" of a table into a local with &
• Track line numbers
• Support binding against multiple values
• Compile tail-calls properly
• Support nested lookup in . form

Changes and Removals

• Rename to Fennel
• Remove deprecated special forms: pack, $, block, *break, special
• Remove redundant defn macro

0.0.1 / 2016-08-14

The initial version (named "fnl") was created in 8 days and then set aside for several years.