## v0.20.0 - XX/XX/2018

### Changes affecting backwards compatibility

- The ``isLower``, ``isUpper`` family of procs in strutils/unicode
  operating on **strings** have been
  deprecated since it was unclear what these do. Note that the much more
  useful procs that operator on ``char`` or ``Rune`` are not affected.

- `strutils.editDistance` has been deprecated,
  use `editdistance.editDistance` or `editdistance.editDistanceAscii`
  instead.

- The OpenMP parallel iterator \``||`\` now supports any `#pragma omp directives`
  and not just `#pragma omp parallel for`. See
  [OpenMP documentation](https://www.openmp.org/wp-content/uploads/OpenMP-4.5-1115-CPP-web.pdf).

  The default annotation is `parallel for`, if you used OpenMP without annotation
  the change is transparent, if you used annotations you will have to prefix
  your previous annotations with `parallel for`.

- The `unchecked` pragma was removed, instead use `system.UncheckedArray`.
- The undocumented ``#? strongSpaces`` parsing mode has been removed.
- The `not` operator is now always a unary operator, this means that code like
  ``assert not isFalse(3)`` compiles.


#### Breaking changes in the standard library

- `osproc.execProcess` now also takes a `workingDir` parameter.

- `options.UnpackError` is no longer a ref type and inherits from `System.Defect` instead of `System.ValueError`.

- nre's `RegexMatch.{captureBounds,captures}[]`  no longer return `Option` or
  `nil`/`""`, respectivly. Use the newly added `n in p.captures` method to
  check if a group is captured, otherwise you'll recieve an exception.

- nre's `RegexMatch.{captureBounds,captures}.toTable` no longer accept a
  default parameter. Instead uncaptured entries are left empty. Use
  `Table.getOrDefault()` if you need defaults.

- nre's `RegexMatch.captures.{items,toSeq}` now returns an `Option[string]`
  instead of a `string`. With the removal of `nil` strings, this is the only
  way to indicate a missing match. Inside your loops, instead of `capture ==
  ""` or `capture == nil`, use `capture.isSome` to check if a capture is
  present, and `capture.get` to get its value.

- nre's `replace()` no longer throws `ValueError` when the replacement string
  has missing captures. It instead throws `KeyError` for named captures, and
  `IndexError` for un-named captures. This is consistant with
  `RegexMatch.{captureBounds,captures}[]`.

- splitFile now correctly handles edge cases, see #10047

#### Breaking changes in the compiler

- The compiler now implements the "generic symbol prepass" for `when` statements
  in generics, see bug #8603. This means that code like this does not compile
  anymore:

```nim
proc enumToString*(enums: openArray[enum]): string =
  # typo: 'e' instead 'enums'
  when e.low.ord >= 0 and e.high.ord < 256:
    result = newString(enums.len)
  else:
    result = newString(enums.len * 2)
```

- ``discard x`` is now illegal when `x` is a function symbol.
- Implicit imports via ``--import: module`` in a config file are now restricted
  to the main package.


### Library additions

- There is a new stdlib module `std/editdistance` as a replacement for the
  deprecated `strutils.editDistance`.

- There is a new stdlib module `std/wordwrap` as a replacement for the
  deprecated `strutils.wordwrap`.

- Added `split`, `splitWhitespace`, `size`, `alignLeft`, `align`,
  `strip`, `repeat` procs and iterators to `unicode.nim`.

- Added `or` for `NimNode` in `macros`.

- Added `system.typeof` for more control over how `type` expressions
  can be deduced.

- Added `macros.isInstantiationOf` for checking if the proc symbol
  is instantiation of generic proc symbol.

- Added the parameter ``isSorted`` for the ``sequtils.deduplicate`` proc.
- There is a new stdlib module `std/diff` to compute the famous "diff"
  of two texts by line.

- Added `os.relativePath`.
- Added `parseopt.remainingArgs`.
- Added `os.getCurrentCompilerExe` (implmented as `getAppFilename` at CT),
  can be used to retrive the currently executing compiler.


### Library changes

- The string output of `macros.lispRepr` proc has been tweaked
  slightly. The `dumpLisp` macro in this module now outputs an
  indented proper Lisp, devoid of commas.

- In `strutils` empty strings now no longer matched as substrings
  anymore.

- Complex type is now generic and not a tuple anymore.

- The `ospaths` module is now deprecated, use `os` instead. Note that
  `os` is available in a NimScript environment but unsupported
  operations produce a compile-time error.

- The `parseopt` module now supports a new flag `allowWhitespaceAfterColon`
  (default value: true) that can be set to `false` for better Posix
  interoperability. (Bug #9619.)

- `os.joinPath` and `os.normalizePath` handle edge cases like ``"a/b/../../.."``
  differently.


### Language additions

- Vm suport for float32<->int32 and float64<->int64 casts was added.
- There is a new pragma block `noSideEffect` that works like
  the `gcsafe` pragma block.
- added os.getCurrentProcessId()
- User defined pragmas are now allowed in the pragma blocks
- Pragma blocks are now longer eliminated from the typed AST tree to preserve
  pragmas for further analysis by macros

### Language changes

- The standard extension for SCF (source code filters) files was changed from
  ``.tmpl`` to ``.nimf``,
  it's more recognizable and allows tools like github to recognize it as Nim,
  see [#9647](https://github.com/nim-lang/Nim/issues/9647).
  The previous extension will continue to work.
- Pragma syntax is now consistent. Previous syntax where type pragmas did not 
  follow the type name is now deprecated. Also pragma before generic parameter
  list is deprecated to be consistent with how pragmas are used with a proc. See
  [#8514](https://github.com/nim-lang/Nim/issues/8514) and 
  [#1872](https://github.com/nim-lang/Nim/issues/1872) for further details.


### Tool changes
- `jsondoc` now include a `moduleDescription` field with the module
  description. `jsondoc0` shows comments as it's own objects as shown in the
  documentation.

### Compiler changes
- The deprecated `fmod` proc is now unavailable on the VM'.

### Bugfixes