Idris 2 version 0.2.1 Released

A new version (0.2.1) of Idris 2 has been released. You can download the source (including generated Scheme and Racket files for bootstrapping) from the download page.

To build it, you can either use a bootstrapping version built in Idris 1, or (the simplest way), run make bootstrap to build from the generated Scheme. Full instructions are in in the distribution.

Documentation is available here. To get started, you can see:

The installation has worked successfully on Linux, Windows, Mac and Raspberry Pi. Please let us know (ideally via the mailing list) how you get on with installing on other platforms.

Note that this is the last version that we guarantee will build with the bootstrapping version. Future versions will require at least Idris 2 version 0.2.1. The main changes since Idris 2 version 0.2.0 are:

Language changes:

  • Bits8, Bits16, Bits32 and Bits64 primitive types added, with:

    • Num, Eq, Ord and Show implementations.
    • Casts from Integer, for literals
    • Casts to Int (except Bits64 which might not fit), Integer and String
    • Passed to C FFI as unsigned
    • Primitives added in Data.Buffer
  • Elaborator reflection and quoting terms

    • Requires extension %language ElabReflection
    • API defined in Language.Reflection, including functions for getting types of global names, constructors of data types, and adding new top level declarations
    • Implemented %macro function flag, to remove the syntactic noise of invoking elaborator scripts. This means the function must always be fully applied, and is run under %runElab
  • Add import X as Y

    • This imports the module X, adding aliases for the definitions in namespace Y, so they can be referred to as Y.
  • do notation can now be qualified with a namespace

    • opens a do block where the >>= operator used is MyDo.(>>=)

Library changes:

  • IO operations in the prelude and base libraries now use the HasIO interface, rather than using IO directly.

  • Experimental Data.Linear.Array added to contrib, supporting mutable linear arrays with constant time read/write, convertible to immutable arrays with constant time read.

    • Anything in Data.Linear in contrib, just like the rest of contrib, should be considered experimental with the API able to change at any time! Further experiments in Data.Linear are welcome :).
  • Experimental Control.Linear.LIO added to contrib, supporting computations which track the multiplicities of their return values, which allows linear resources to be tracked.

  • Added Control.Monad.ST, for update in-place via STRef (which is like IORef, but can escape from IO). Also added Data.Ref which provides an interface to both IORef and STRef.

  • Added Control.ANSI in contrib, for usage of ANSI escape codes for text styling and cursor/screen control in terminals.

Command-line options changes:

  • Removed --ide-mode-socket-with option. --ide-mode-socket now accepts an optional host:port argument.
  • Added options to override source directory, build directory and output directory: --source-dir, --build-dir, --output-dir.
    • These options are also available as fields in the package description: sourcedir, builddir, outputdir.

Compiler changes:

  • It is now possible to create new backends with minimal overhead. Idris.Driver exposes the function mainWithCodegens that takes a list of codegens. The feature is documented here.
  • New code generators node and javascript.

REPL/IDE mode changes:

  • Implemented :module command, to load a module during a REPL session.
  • Implemented :doc, which displays documentation for a name.
  • Implemented :browse, which lists the names exported by a namespace.
  • Added :psnext, which continues the previous proof search, looking for the next type correct expression
    • Correspondingly, added the IDE mode command proof-search-next (which takes no arguments)
  • Added :gdnext, which continues the previous program search, looking for the next type correct implementation
    • Correspondingly, added the IDE mode command generate-def-next (which takes no arguments)
  • Improved program search to allow deconstructing intermediate values, and in simple cases, the result of recursive calls.

Any issues you do find, please report via the github issue tracker. We may not be able to fix them quickly (there's not many of us working on this full time after all) but it's still useful to know what they are!

Thanks to the many people who have contributed, whether by adding features, fixing code, reporting issues, or anything else. You can find a list of contributors in the GitHub repository.

Have fun!