Tags: rahulmutt/Idris-dev
Tags
New in 0.99.1:
Language updates
* Language pragmas now required for the less stable existing features, in
addition to the existing `TypeProviders` and `ErrorReflection`:
+ `ElabReflection`, which must be enabled to use `%runElab`
+ `UniquenessTypes`, which must be enabled to use `UniqueType`
+ `DSLNotation`, which must be enabled to define a `dsl` block
+ `FirstClassReflection`, which must be enabled to define a `%reflection`
function
* New language extension `LinearTypes`:
+ This allows adding a /multiplicity/ to a binder which says how often it
is allowed to be used; either 0 or 1 (if unstated, multiplicity is "many")
+ The typing rules follow Conor McBride's paper "I Got Plenty o' Nuttin'"
+ This is highly experimental, unfinished, not at all polished. and there
are still lots of details to sort out. Some features don't quite work
properly yet. But it is there to play with for the brave!
Tool Updates
+ Idris' output has been updated to more accurately reflect its
progress through the compiler i.e. Type Checking; Totality Checking;
IBC Generation; Compiling; and Code Generation. To control the
loudness of the reporting three verbosity levels are introduced:
`--V0`, `--V1`, and `--V2`. The old aliases of `-V` and `--verbose`
persist.
+ New REPL command `:!` that runs an external shell command.
+ The REPL now colourises output on MinTTY consoles (e.g., Cygwin and MSYS)
on Windows, which previously did not occur due to a bug.
+ Idris now runs in a UTF-8-compatible codepage on Windows. This fixes many
Unicode-rendering issues on Windows (e.g., error messages stating
`commitBuffer: invalid argument (invalid character)`).
+ Idris now has a `--warnipkg` flag to enable auditing of Idris
packages during build time. Currently auditing check's the list of
modules specified in the `iPKG` file with those presented in the
package directory.
Library Updates
+ Terminating programs has been improved with more appropriate
functions (`exitWith`, `exitFailure`, and `exitSuccess`) and a data
structure (`ExitCode`) to capture a program's return code.
+ Casting a `String` to an `Int`, `Integer` or a `Double` now ignores leading
and trailing whitespace. Previously only leading whitespace was ignored.
+ RTS functions `openFile`, `do_popen`, and `ARGV` are now properly encoded using UTF-8 on Windows.
* `record` syntax now allows updating fields, including nested fields,
by applying a function using the `$=` operator. For example:
```idris
record Score where
constructor MkScore
correct : Nat
attempted : Nat
record GameState where
constructor MkGameState
score : Score
difficulty : Nat
correct : GameState -> GameState
correct st = record { score->correct $= (+1),
score->attempted $= (+1) } st
```
* Implicit parameter to interfaces are now allowed. For example:
```idris
interface Shows (ts : Vect k Type) where
shows : HVect ts -> Vect k String
```
In this interface, `k` is an implicit parameter, but previously needed to
be explicit
* The File Effect has been updated to take into account changes in
`Prelude.File` and to provide a 'better' API.
* `natEnumFromThen` and `natEnumFromTo` have been updated to correctly calculate reverse ranges. Range syntax `[a,b..c]` now can be used again to generate reverse ranges.
* `divBN` and `modBN` now can only be used for unsigned numbers.
* `return`, which has been an alias for `pure` for many releases, is now deprecated.
* Replace instance with implementation:
+ `InstanceN` is deprecated, use `ImplementationN` instead.
+ `InstanceCtorN` is deprecated, use `ImplementationCtorN` instead.
+ `addInstance` is deprecated, use `addImplementation` instead.
+ `%instance` keyword is deprecated, use `%implementation` instead.
* Idris packages are now installed within a sub-directory `libs` of Idris' data directory, before they were installed in the directory's root.
* Idris' documentation system now displays the documentation for auto
implicits in the output of `:doc`. This is tested for in `docs005`.
* New command line flag `--info` that displays information about the installation.
* New command line flag `--sourcepath <dir>` that allows adding directories to the source search path.
* Allow 'installation' of a package's IdrisDoc documentation into a central location. The default location is the subdirectory `docs` of Idris' data directory.
* New flag `--installdoc <ipkg>` provided to install documentation
* New flag `--docdir` provided to show default documentation installation location.
* New environment variable `IDRIS_DOC_PATH` to allow specification of an alternative installation path for documentation.
* Semantic meaning behind several environment variables has been clarified in documentation and code. See compilation section of the reference manual for more details.
* Interface parameter constraints are now printed in the output of `:doc`. This
is tested for in `docs006`.
* New, faster, better, implementation of the coverage checker
* The test suite now uses [tasty-golden](https://hackage.haskell.org/package/tasty-golden). New tests must be registered in `test/TestData.hs`, as explained in the relevant `README.md`.
* Added OSX and Windows continous integration with Travis and Appveyor.
* The :e command can now handle an $EDITOR with arguments in it, like "emacs -nw"
* `rewrite` can now be used to rewrite equalities on functions over
dependent types
* `rewrite` can now be given an optional rewriting lemma, with the syntax
`rewrite [rule] using [rewrite_lemma] in [scope]`.
* Reorganised elaboration of `implementation`, so that interfaces with
dependencies between methods now work more smoothly
* Allow naming of parent implementations when defining an implementation.
For example:
```
[PlusNatSemi] Semigroup Nat where
(<+>) x y = x + y
[MultNatSemi] Semigroup Nat where
(<+>) x y = x * y
-- use PlusNatSemi as the parent implementation
[PlusNatMonoid] Monoid Nat using PlusNatSemi where
neutral = 0
-- use MultNatSemi as the parent implementation
[MultNatMonoid] Monoid Nat using MultNatSemi where
neutral = 1
```
* Interface definitions can now include data declarations (but not data
definitions). Any implementation of the interface must define the method
using a data type. The effect is to cause Idris to treat the method as
a data type (for unification and interface resolution purposes).
* Experimentally, allow named implementations to be available by default in a
block of declarations with `using` notation. For example:
```
using implementation PlusNatMonoid
test : Nat -> Nat
test x = x <+> x <+> neutral
```
* Constraint arguments can now appear anywhere in function types, not just
at the top level or after an implicit argument binding.
* Experimental extended `with` syntax, which allows calling functions defined
in a with block directly. For example:
```
data SnocList : List a -> Type where
Empty : SnocList []
Snoc : SnocList xs -> SnocList (xs ++ [x])
snocList : (xs : List a) -> SnocList a
my_reverse : List a -> List a
my_reverse xs with (snocList xs)
my_reverse [] | Empty = []
my_reverse (ys ++ [x]) | (Snoc p) = x :: my_reverse ys | p
```
The `| p` on the right hand side means that the `with` block function will
be called directly, so the recursive structure of `SnocList` can direct the
recursion structure of `my_reverse`.
* Added `%fragile` directive, which gives a warning and a message when a
fragile name is referenced. For use in detailing fragile APIs.
* The totality checker now looks under `case` blocks, rather than treating
them as mutually defined functions with their top level function, meaning
that it can spot more total functions.
* The totality checker now looks under `if...then...else` blocks when checking
for productivity.
* The `%assert_total` directive is now deprecated. Instead, you can
use one of the functions `assert_total`, `assert_smaller` or
`assert_unreachable` to describe more precisely where a totality assertion
is needed.
* `Control.WellFounded` module removed, and added to the Prelude as
`Prelude.WellFounded`.
* Added `Data.List.Views` with views on `List` and their covering functions.
* Added `Data.Nat.Views` with views on `Nat` and their covering functions.
* Added `Data.Primitives.Views` with views on various primitive types and their covering functions.
* Added `System.Concurrency.Sessions` for simple management of conversations
between processes
* Taking cues from cabal, the `iPKG` format has been extended to
include more package metadata information. The following fields
have been added:
+ `brief`: Brief description of the package.
+ `version`: Version string to associate with the package.
+ `readme`: Location of the README file.
+ `license`: Description of the licensing information.
+ `author`: Author information.
+ `maintainer`: Maintainer information.
+ `homepage`: Website associated with the package.
+ `sourcepage`: Location of the DVCS where the source can be found.
* The Idris man page is now installed as part of the cabal/stack build process.
* Improved startup performance by reducing the processing of an already imported
module that has changed accessibility.
* A limited set of command line options can be used to override
package declared options. Overridable options are currently, logging
level and categories, default totality check, warn reach, IBC output
folder, and idris path. Note overriding IBC output folder, only
affects the installation of Idris packages.
* Remove deprecated options `--ideslave` and `--ideslave-socket`. These options
were replaced with `--ide-mode` and `--ide-mode-socket` in 0.9.17
* The code generator output type `MavenProject` was specific to the
Java codegen and has now been deprecated, together with the
corresponding `--mvn` option.
* Definitional equality on Double is now bit-pattern identity rather
than IEEE's comparison operator. This prevents a bug where programs
could distinguish between -0.0 and 0.0, but the type theory could
not, leading to a contradiction. The new fine-grained equality
prevents this.
* Naming conventions for Idris packages in an iPKG file now follow the
same rules for executables. Unquoted names must be valid namespaced
Idris identifiers e.g. ``package my.first.package``. Quoted package
names allow for packages to be given valid file names, for example,
``package "my-first-package"``.
* The implicit coercion from String to TTName was removed.
* Decidable equality for TTName is available.
New in 0.11:
============
Updated export rules
--------------------
* The export rules are:
- 'private' means that the definition is not exported at all
- 'export' means that the top level type is exported, but not the
definition. In the case of 'data', this means the type constructor is
exported but not the data constructors.
- 'public export' means that the entire definition is exported.
* By default, names are 'private'. This can be altered with an %access
directive as before.
* Exported types can only refer to other exported names
* Publicly exported definitions can only refer to publicly exported names
Improved C FFI
--------------
* Idris functions can now be passed as callbacks to C functions or wrapped
in a C function pointer.
* C function pointers can be called.
* Idris can access pointers to C globals.
Effects
-------
* Effects can now be given in any order in effect lists (there is no need
for the ordering to be preserved in sub lists of effects)
Elaborator reflection updates
-----------------------------
* Datatypes can now be defined from elaborator reflection:
- declareDatatype adds the type constructor declaration to the context
- defineDatatype adds the constructors to the datatype
- To declare an inductive-recursive family, declare the types of the
function and the type constructor before defining the pattern-match
cases and constructors.
Minor language changes
----------------------
* The '[static]' annotation is changed to '%static' to be consistent with the
other annotations.
* Added '%auto_implicits' directive. The default is '%auto_implicits on'.
Placing '%auto_implicits off' in a source file means that after that
point, any implicit arguments must be bound, e.g.:
append : {n,m,a:_} -> Vect n a -> Vect m a -> Vect (n + m) a
Only names which are used explicitly in the type need to be bound, e.g.:
Here : {x, xs : _} -> Elem x (x :: xs)
In 'Here', there is no need to bind any of the variables in the type of
'xs' (it could be e.g. List a or Vect n a; 'a' and 'n' will still be
implicitly bound).
You can still implicitly bind with 'using':
using (xs : Vect _ _)
data Elem : {a, n : _} -> a -> Vect n a -> Type where
Here : {x : _} -> Elem x (x :: xs)
There : {x, y : _} -> Elem x xs -> Elem x (y :: xs)
However, note that *only* names which appear in *both* the using block
*and* the type being defined will be implicitly bound. The following will
therefore fail because 'n' isn't implicitly bound:
using (xs : Vect n a)
bad : Elem x xs -> Elem x (y :: xs)
* `Sigma` has been renamed to `DPair`.
* Accessor functions for dependent pairs have been renamed to bring them into
line with standard accessor functions for pairs. The function `getWitness`
is now `fst`, and `getProof` is `snd`.
* File Modes expanded: Append, ReadWriteTruncate, and ReadAppend added,
Write is deprecated and renamed to WriteTruncate.
* C11 Extended Mode variations added to File Modes.
* More flexible holes.
Holes can now depend on other holes in a term (such as implicit arguments
which may be inferred from the definition of the hole).
* Programs with holes can now be compiled.
Attempting to evaluate an expression with a hole results in a run time error.
* Dependent pairs now can be specified using a telescope-style syntax, without
requirement of nesting, e.g. it is possible to now write the following:
(a : Type ** n : Nat ** Vect n a)
* Idris will give a warning if an implicit is bound automatically, but would
otherwise be a valid expressio if the name was used as a global
External Dependencies
---------------------
* Curses has been removed as an external dependancy.
PreviousNext