CHANGELOG_NEXT.md

This CHANGELOG describes the merged but unreleased changes. Please see CHANGELOG for changes to all previously released versions of Idris2. All new PRs should target this file (CHANGELOG_NEXT).

Changelog

[Next version]

CLI changes

• The idris2 --list-packages command now outputs information about the location and available TTC versions for each package it finds. It also shows the current Idris2 TTC version so you can spot packages that do not have a compatible TTC install. The TTC version tracks breaking changes to the compiled binary format of Idris2 code and it is separate from Idris2's semantic version (e.g. 0.7.0). A library without the correct TTC version installed will be ignored by the compiler when it tries to use that library as a dependency for some other package.

• The idris2 --help pragma command now outputs the %hint pragma.

• The idris2 --init command now ensures that package names are valid Idris2 identifiers.

• A new idris2 --dump-installdir {ipkg-filename} command outputs the file path where Idris2 will install the given package if idris2 --install {ipkg-filename} is called.

Building/Packaging changes

• The Nix flake's buildIdris function now returns a set with executable and library attributes. These supersede the now-deprecated build and installLibrary attributes. executable is the same as build and library is a function that takes an argument determining whether the library should be installed with sourcecode files or not; other than that, library functionally replaces installLibrary.

• The Nix flake's buildIdris executable property (previously build) has been fixed in a few ways. It used to output a non-executable file for NodeJS builds (now the file has the executable bit set). It used to output the default Idris2 wrapper for Scheme builds which relies on utilities not guaranteed at runtime by the Nix derivation; now it rewraps the output to only depend on the directory containing Idris2's runtime support library.

• The Nix flake now exposes the Idris2 API package as idris2Api and Idris2's C support library as support.

• A new idris2 --dump-ipkg-json option (requires either --find-ipkg or specifying the .ipkg file) dumps JSON information about an Idris package.

• Support for macOS PowerPC added.

• Multiline comments {- text -} are now supported in ipkg files.

Language changes

• Autobind and Typebind modifier on operators allow the user to customise the syntax of operator to look more like a binder. See #3113.

• Fixity declarations without an export modifier now emit a warning in peparation for a future version where they will become private by default.

• Elaborator scripts were made to be able to access the visibility modifier of a definition, via getVis.

• The language now has a %foreign_impl pragma to add additional languages to a %foreign function.

• Bind expressions in do blocks can now have a type ascription. See #3327.

Compiler changes

• The compiler now differentiates between "package search path" and "package directories." Previously both were combined (as seen in the idris2 --paths output for "Package Directories"). Now entries in the search path will be printed under an "Package Search Paths" entry and package directories will continue to be printed under "Package Directories." The IDRIS2_PACKAGE_PATH environment variable adds to the "Package Search Paths." Functionally this is not a breaking change.

• The compiler now supports impossible in a non-case lambda. You can now write \ Refl impossible.

• The compiler now parses ~x.fun as unquoting x rather than x.fun and ~(f 5).fun as unquoting (f 5) rather than (f 5).fun.

• LHS of with-applications are parsed as PWithApp instead of PApp. As a consequence, IWithApp appears in TTImp values in elaborator scripts instead of IApp, as it should have been.

• MakeFuture primitive is removed.

• Typst files can be compiled as Literate Idris

Backend changes

RefC Backend

• Compiler can emit precise reference counting instructions where a reference is dropped as soon as possible. This allows you to reuse unique variables and optimize memory consumption.

• Fix invalid memory read in strSubStr.

• Fix memory leaks of IORef. Now that IORef holds values by itself, global_IORef_Storage is no longer needed.

• Pattern matching generates simpler code. This reduces malloc/free and memory consumption. It also makes debugging easier.

• Stopped useless string copying in the constructor to save memory. Also, name generation was stopped for constructors that have tags.

• Special constructors such as Nil and Nothing were eliminated and assigned to NULL.

• Unbox Bits32, Bits16, Bits8, Int32, Int16, Int8. These types are now packed into Value*. Now, RefC backend requires at least 32 bits for pointers. 16-bit CPUs are no longer supported. And we expect the address returned by malloc to be aligned with at least 32 bits. Otherwise it cause a runtime error.

• Rename C function to avoid confliction. But only a part.

• Supress code generation of _arglist wrappers to reduce code size and compilation time.

• Removed Value_Arglist to reduce Closure's allocation overhead and make code simply.

• Switch calling conventions based on the number of arguments to avoid limits on the number of arguments and to reduce stack usage.

• Values that reference counters reaching their maximum limit are immortalized to prevent counter overflow. This can potentially cause memory leaks, but they occur rarely and are a better choice than crashing. Since overflow is no longer a concern, changing refCounter from int to uint16 reduces the size of 'Value_Header'.

• Values often found at runtime, such as integers less than 100 are generate staticaly and share.

• Constant String, Int64, Bits64 and Double values are allocated statically as imortal and shared.

Chez

• Fixed CSE soundness bug that caused delayed expressions to sometimes be eagerly evaluated. Now when a delayed expression is lifted by CSE, it is compiled using Scheme's delay and force to memoize them.

• More efficient collect-request-handler is used.

• Add a codegen directive called lazy=weakMemo to make Lazy and Inf values weakly memoised. That is, once accessed, they are allowed to be not re-evaluated until garbage collector wipes them.

Racket

• Fixed CSE soundness bug that caused delayed expressions to sometimes be eagerly evaluated. Now when a delayed expression is lifted by CSE, it is compiled using Scheme's delay and force to memoize them.

• Add a codegen directive called lazy=weakMemo to make Lazy and Inf values weakly memoised. That is, once accessed, they are allowed to be not re-evaluated until garbage collector wipes them.

NodeJS Backend

• The NodeJS executable output to build/exec/ now has its executable bit set. That file already had a NodeJS shebang at the top, so now it is fully ready to go after compilation.

Library changes

Prelude

• Added pipeline operators (|>) and (<|).

Base

• Data.List.Lazy was moved from contrib to base.

• Added an Interpolation implementation for primitive decimal numeric types and Nat.

• Added append (++) for List version of All.

• Moved helpers and theorems from contrib's Data.HVect into base's Data.Vect.Quantifiers.All namespace. Some functions were renamed and some already existed. Others had quantity changes -- in short, there were some breaking changes here in addition to removing the respective functions from contrib. If you hit a breaking change, please take a look at the PR and determine if you simply need to update a function name or if your use-case requires additional code changes in the base library. If it's the latter, open a bug ticket or start a discussion on the Idris Discord to determine the best path forward.

• Deprecate bufferData in favor of bufferData'. These functions are the same with the exception of the latter dealing in Bits8 which is more correct than Int.

• Added an alternative TTImp traversal function mapATTImp' taking the original TTImp at the input along with already traversed one. Existing mapATTImp is implemented through the newly added one. The similar alternative for mapMTTImp is added too.

• Removed need for the runtime value of the implicit argument in succNotLTEpred.

• Added utility functions insertWith, insertFromWith and fromListWith for SortedMap.

• Implemented leftMost and rightMost for SortedSet.

• Added funExt0 and funExt1, functions analogous to funExt but for functions with quantities 0 and 1 respectively.

• SortedSet, SortedMap and SortedDMap modules were extended with flipped variants of functions like lookup, contains, update and insert.

• Moved definition of Data.Vect.nubBy to the global scope as nubByImpl to allow compile time proofs on nubBy and nub.

• Removed need for the runtime value of the implicit length argument in Data.Vect.Elem.dropElem.

• Some pieces of Data.Fin.Extra from contrib were moved to base to modules Data.Fin.Properties, Data.Fin.Arith and Data.Fin.Split.

• Decidable.Decidable.decison is now public export.

• Functor is implemented for PiInfo from Language.Reflection.TT.

• Quantity of the argument for the type being searched in the search function from Language.Reflection was changed to be zero.

• Added fromRight and fromLeft for extracting values out of Either, equivalent to fromJust for Just.

• Export System.Signal.signalCode and System.Signal.toSignal.

• Added implementations of Foldable and Traversable for Control.Monad.Identity

• Added Data.IORef.atomically for the chez backend.

Contrib

• Data.List.Lazy was moved from contrib to base.

• Existing System.Console.GetOpt was extended to support errors during options parsing in a backward-compatible way.

• Moved helpers from Data.HVect to base library's Data.Vect.Quantifiers.All and removed Data.HVect from contrib. See the additional notes in the CHANGELOG under the Library changes/Base section above.

• Some pieces of Data.Fin.Extra from contrib were moved to base to modules Data.Fin.Properties, Data.Fin.Arith and Data.Fin.Split.

• Function invFin from Data.Fin.Extra was deprecated in favour of Data.Fin.complement from base.

• The Control.Algebra library from contrib has been removed due to being broken, unfixed for years, and on several independent occasions causing confusion with people picking up Idris and trying to use it.

  • Detailed discussion can be found in Idris2#72.
  • For reasoning about algebraic structures and proofs, please see Frex and idris2-algebra.

• Since they depend on Control.Algebra, the following contrib libraries have also been removed:

  • Control/Monad/Algebra.idr
  • Data/Bool/Algebra.idr
  • Data/List/Algebra.idr
  • Data/Morphisms/Algebra.idr
  • Data/Nat/Algebra.idr

• prim__makeFuture from System.Future is reimplemented as %foreign instead of using now removed MakeFuture primitive

Network

• Add a missing function parameter (the flag) in the C implementation of idrnet_recv_bytes

Test

• Replaced Requirement data type with a new record that can be used to create any requirement needed. The constructors for the old Requirement type are now functions of the same names that return values of the new record type so in most situations there should be no compatibility issues.

Documentation

• Module docstrings are now displayed for namespace indexes when documentation is built via --mkdoc.
• Generated documentation are now removed via --clean.