# Changelog
All notable changes to this project will be documented in this file.

The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).

## [Unreleased]
### Added
### Changed
### Removed

## [4.2.0] - 2020-01-15
### Added
- Allow separate entrypoint/function type signature and definition, and pattern
  matching in left-hand sides:
  ```
    function
      length : list('a) => int
      length([])      = 0
      length(x :: xs) = 1 + length(xs)
  ```
- Allow pattern matching in list comprehension generators (filtering out match
  failures):
  ```
    function somes(xs : list(option('a))) : list('a) =
      [ x | Some(x) <- xs ]
  ```
- Allow pattern matching in let-bindings (aborting on match failures):
  ```
    function test(m : map(int, int)) =
        let Some(x) = Map.lookup(m, 0)
        x
  ```
### Changed
- FATE code generator improvements.
- Bug fix: Handle qualified constructors in patterns.
- Bug fix: Allow switching also on negative numbers.
### Removed

## [4.1.0] - 2019-11-26
### Added
- Support encoding and decoding bit fields in call arguments and results.
### Changed
- Various improvements to FATE code generator.
### Removed

## [4.0.0] - 2019-10-11
### Added
- `Address.to_contract` - casts an address to a (any) contract type.
- Pragma to check compiler version, e.g. `@compiler >= 4.0`.
- Handle numeric escapes, i.e. `"\x19Ethereum Signed Message:\n"`, and similar strings.
- `Bytes.concat` and `Bytes.split` are added to be able to
  (de-)construct byte arrays.
- `[a..b]` language construct, returning the list of numbers between
  `a` and `b` (inclusive). Returns the empty list if `a` > `b`.
- [Standard libraries] (https://github.com/aeternity/protocol/blob/master/contracts/sophia_stdlib.md)
- Checks that `init` is not called from other functions.
- FATE backend - the compiler is able to produce VM code for both `AEVM` and `FATE`. Many
  of the APIs now take `{backend, aevm | fate}` to decide wich backend to produce artifacts
  for.
- New builtin functions `Crypto.ecrecover_secp256k1: (hash, bytes(65)) => option(bytes(20))`
  and `Crypto.ecverify_secp256k1 : (hash, bytes(20), bytes(65)) => bool` for recovering
  and verifying an Ethereum address for a message hash and a signature.
- Sophia supports list comprehensions known from languages like Python, Haskell or Erlang.
  Example syntax:
```
[x + y | x <- [1,2,3,4,5], let k = x*x, if (k > 5), y <- [k, k+1, k+2]]
// yields [12,13,14,20,21,22,30,31,32]
```
- A new contract, and endpoint, modifier `payable` is introduced. Contracts, and enpoints,
  that shall be able to receive funds should be marked as payable. `Address.is_payable(a)`
  can be used to check if an (contract) address is payable or not.
### Changed
- Nice type error if contract function is called as from a namespace.
- Fail on function definitions in contracts other than the main contract.
- Bug fix in variable optimization - don't discard writes to the store/state.
- Bug fixes in error reporting.
- Bug fix in variable liveness analysis for FATE.
- Error messages are changed into a uniform format, and more helpful
  messages have been added.
- `Crypto.<hash_fun>` and `String.<hash_fun>` for byte arrays now only
  hash the actual byte array - not the internal ABI format.
- More strict checks for polymorphic oracles and higher order oracles
  and entrypoints.
- `AENS.claim` is updated with a `NameFee` field - to be able to do
  name auctions within contracts.
- Fixed a bug in `Bytes.to_str` for AEVM.
- New syntax for tuple types. Now 0-tuple type is encoded as `unit` instead of `()` and
  regular tuples are encoded by interspersing inner types with `*`, for instance `int * string`.
  Parens are not necessary. Note it only affects the types, values remain as their were before,
  so `(1, "a") : int * string`
- The `AENS.transfer` and `AENS.revoke` functions have been updated to take a name `string`
  instead of a name `hash`.
- Fixed a bug where the `AEVM` backend complained about a missing `init` function when
  trying to generate calldata from an ACI-generated interface.
- Compiler now returns the ABI-version in the compiler result map.
- Renamed `Crypto.ecverify` and `Crypto.ecverify_secp256k1` into `Crypto.verify_sig` and
  `Crypto.verify_sig_secp256k1` respectively.
### Removed

## [3.2.0] - 2019-06-28
### Added
- New builtin function `require : (bool, string) => ()`. Defined as
    ```
    function require(b, err) = if(!b) abort(err)
    ```
- New builtin functions
    ```
    Bytes.to_str : bytes(_) => string
    Bytes.to_int : bytes(_) => int
    ```
  for converting a byte array to a hex string and interpreting it as a
  big-endian encoded integer respectively.
### Changed
- Public contract functions must now be declared as *entrypoints*:
  ```
  contract Example =
    // Exported
    entrypoint exported_fun(x) = local_fun(x)
    // Not exported
    function local_fun(x) = x
  ```
  Functions in namespaces still use `function` (and `private function` for
  private functions).
- The return type of `Chain.block_hash(height)` has changed, it used to
  be `int`, where `0` denoted an incorrect height. New return type is
  `option(hash)`, where `None` represents an incorrect height.
- Event name hashes now use BLAKE2b instead of Keccak256.
- Fixed bugs when defining record types in namespaces.
- Fixed a bug in include path handling when passing options to the compiler.
### Removed

## [3.1.0] - 2019-06-03
### Added
### Changed
- Keyword `indexed` is now optional for word typed (`bool`, `int`, `address`,
  ...) event arguments.
- State variable pretty printing now produce `'a, 'b, ...` instead of `'1, '2, ...`.
- ACI is restructured and improved:
    - `state` and `event` types (if present) now appear at the top level.
    - Namespaces and remote interfaces are no longer ignored.
    - All type definitions are included in the interface rendering.
    - API functions are renamed, new functions are `contract_interface`
      and `render_aci_json`.
- Fixed a bug in `create_calldata`/`to_sophia_value` - it can now handle negative
  literals.
### Removed

## [3.0.0] - 2019-05-21
### Added
- `stateful` annotations are now properly enforced. Functions must be marked stateful
  in order to update the state or spend tokens.
- Primitives `Contract.creator`, `Address.is_contract`, `Address.is_oracle`,
  `Oracle.check` and `Oracle.check_query` has been added to Sophia.
- A byte array type `bytes(N)` has been added to generalize `hash (== bytes(32))` and
  `signature (== bytes(64))` and allow for byte arrays of arbitrary fixed length.
- `Crypto.ecverify_secp256k1` has been added.
### Changed
- Address literals (+ Oracle, Oracle query and remote contracts) have been changed
  from `#<hex>` to address as `ak_<base58check>`, oracle `ok_<base58check>`,
  oracle query `oq_<base58check>` and remote contract `ct_<base58check>`.
- The compilation and typechecking of `letfun` (e.g. `let m(f, xs) = map(f, xs)`) was
  not working properly and has been fixed.
### Removed
- `let rec` has been removed from the language, it has never worked.
- The standalone CLI compiler is served in the repo `aeternity/aesophia_cli` and has
  been completely removed from `aesophia`.

## [2.1.0] - 2019-04-11
### Added
- Stubs (not yet wired up) for compilation to FATE
- Add functions specific for Calldata decoding
- Support for `Auth.tx_hash`, not available in AEVM until Fortuna release

### Changed
- Improvements to the ACI generator

## [2.0.0] - 2019-03-11
### Added
- Add `Crypto.ecverify` to the compiler.
- Add `Crypto.sha3`, `Crypto.blake2`, `Crypto.sha256`, `String.blake2` and
  `String.sha256` to the compiler.
- Add the `bits` type for working with bit fields in Sophia.
- Add Namespaces to Sophia in order to simplify using library contracts, etc.
- Add a missig type check on the `init` function - detects programmer errors earlier.
- Add the ACI (Aeternity Contract Interface) generator.

### Changed
- Use native bit shift operations in builtin functions, reducing gas cost.
- Improve type checking of `record` fields - generates more understandable error messages.
- Improved, more coherent, error messages.
- Simplify calldata creation - instead of passing a compiled contract, simply
  pass a (stubbed) contract string.

[Unreleased]: https://github.com/aeternity/aesophia/compare/v4.2.0...HEAD
[4.2.0]: https://github.com/aeternity/aesophia/compare/v4.2.0...v4.1.0
[4.1.0]: https://github.com/aeternity/aesophia/compare/v4.1.0...v4.0.0
[4.0.0]: https://github.com/aeternity/aesophia/compare/v4.0.0...v3.2.0
[3.2.0]: https://github.com/aeternity/aesophia/compare/v3.1.0...v3.2.0
[3.1.0]: https://github.com/aeternity/aesophia/compare/v3.0.0...v3.1.0
[3.0.0]: https://github.com/aeternity/aesophia/compare/v2.1.0...v3.0.0
[2.1.0]: https://github.com/aeternity/aesophia/compare/v2.0.0...v2.1.0
[2.0.0]: https://github.com/aeternity/aesophia/tag/v2.0.0
