Nim/changelog.md

v0.19.X - XX/XX/2018

Changes affecting backwards compatibility

• The stdlib module future has been renamed to sugar.
• macros.callsite is now deprecated. Since the introduction of varargs parameters this became unnecessary.
• Anonymous tuples with a single element can now be written as (1,) with a trailing comma. The underlying AST is nnkTupleConst(newLit 1) for this example. nnkTupleConstr is a new node kind your macros need to be able to deal with!
• Indexing into a cstring for the JS target is now mapped to charCodeAt.
• Assignments that would "slice" an object into its supertype are now prevented at runtime. Use ref object with inheritance rather than object with inheritance to prevent this issue.
• The not nil type annotation now has to be enabled explicitly via {.experimental: "notnil"} as we are still not pleased with how this feature works with Nim's containers.
• The parser now warns about inconsistent spacing around binary operators as these can easily be confused with unary operators. This warning will likely become an error in the future.
• The 'c and 'C' prefix for octal literals is now deprecated to bring the language in line with the standard library (e.g. parseOct).

Breaking changes in the standard library

• re.split for empty regular expressions now yields every character in the string which is what other programming languages chose to do.

• The returned tuple of system.instantiationInfo now has a third field containing the column of the instantiation.

• cookies.setCookie no longer assumes UTC for the expiration date.

• strutils.formatEng does not distinguish between nil and "" strings anymore for its unit parameter. Instead the space is controlled by a new parameter useUnitSpace.

• proc `-`*(a, b: Time): int64 in the times module has changed return type to times.Duration in order to support higher time resolutions. The proc is no longer deprecated.

• posix.Timeval.tv_sec has changed type to posix.Time.

• math.`mod` for floats now behaves the same as mod for integers (previously it used floor division like Python). Use math.floorMod for the old behavior.

• For string inputs, unicode.isUpper and unicode.isLower now require a second mandatory parameter skipNonAlpha.

• For string inputs, strutils.isUpperAscii and strutils.isLowerAscii now require a second mandatory parameter skipNonAlpha.

• osLastError is now marked with sideEffect

• The procs parseHexInt and parseOctInt now fail on empty strings and strings containing only valid prefixes, e.g. "0x" for hex integers.

• terminal.setCursorPos and terminal.setCursorXPos now work correctly with 0-based coordinates on POSIX (previously, you needed to use 1-based coordinates on POSIX for correct behaviour; the Windows behaviour was always correct).

Breaking changes in the compiler

• The undocumented #? braces parsing mode was removed.
• The undocumented PHP backend was removed.

Library additions

• re.split now also supports the maxsplit parameter for consistency with strutils.split.
• Added system.toOpenArray in order to support zero-copy slicing operations. This is currently not yet available for the JavaScript target.
• Added getCurrentDir, findExe, cpDir and mvDir procs to nimscript.
• The times module now supports up to nanosecond time resolution when available.
• Added the type times.Duration for representing fixed durations of time.
• Added the proc times.convert for converting between different time units, e.g days to seconds.
• Added the proc algorithm.binarySearch[T, K] with the cmp parameter.
• Added the proc algorithm.upperBound.
• Added inverse hyperbolic functions, math.arcsinh, math.arccosh and math.arctanh procs.
• Added cotangent, secant and cosecant procs math.cot, math.sec and math.csc; and their hyperbolic, inverse and inverse hyperbolic functions, math.coth, math.sech, math.csch, math.arccot, math.arcsec, math.arccsc, math.arccoth, math.arcsech and math.arccsch procs.
• Added the procs math.floorMod and math.floorDiv for floor based integer division.
• Added the procs rationals.`div```, rationals.`mod```, rationals.floorDiv and rationals.floorMod for rationals.
• Added the proc math.prod for product of elements in openArray.
• Added the proc parseBinInt to parse a binary integer from a string, which returns the value.
• parseOct and parseBin in parseutils now also support the maxLen argument similar to parseHexInt
• Added the proc flush for memory mapped files.
• Added the MemMapFileStream.

Library changes

• macros.astGenRepr, macros.lispRepr and macros.treeRepr now escapes the content of string literals consistently.
• macros.NimSym and macros.NimIdent is now deprecated in favor of the more general NimNode.
• macros.getImpl now includes the pragmas of types, instead of omitting them.
• macros.hasCustomPragma and macros.getCustomPragmaVal now also support ref and ptr types, pragmas on types and variant fields.
• system.SomeReal is now called SomeFloat for consistency and correctness.
• algorithm.smartBinarySearch and algorithm.binarySearch is now joined in binarySearch. smartbinarySearch is now deprecated.
• The terminal module now exports additional procs for generating ANSI color codes as strings.
• Added the parameter val for the CritBitTree[int].inc proc.
• An exception raised from a test block of unittest now shows its type in error message.
• The compiler/nimeval API was rewritten to simplify the "compiler as an API". Using the Nim compiler and its VM as a scripting engine has never been easier. See tests/compilerapi/tcompilerapi.nim for an example of how to use the Nim VM in a native Nim application.
• Added the parameter val for the CritBitTree[T].incl proc.
• The proc tgamma was renamed to gamma. tgamma is deprecated.
• The pegs module now exports getters for the fields of its Peg and NonTerminal object types. Pegs with child nodes now have the standard items and pairs iterators.

Language additions

• Dot calls combined with explicit generic instantiations can now be written as x.y[:z] which is transformed into y[z](x) by the parser.
• func is now an alias for proc {.noSideEffect.}.
• In order to make for loops and iterators more flexible to use Nim now supports so called "for-loop macros". See the manual <manual.html#macros-for-loop-macros>_ for more details.
• the typedesc special type has been renamed to just type.
• static and type are now also modifiers similar to ref and ptr. They denote the special types static[T] and type[T].
• Forcing compile-time evaluation with static now supports specifying the desired target type (as a concrete type or as a type class)
• The type operator now supports checking that the supplied expression matches an expected type constraint.

Language changes

• The importcpp pragma now allows importing the listed fields of generic C++ types. Support for numeric parameters have also been added through the use of static[T] types. (#6415)

• Native C++ exceptions can now be imported with importcpp pragma. Imported exceptions can be raised and caught just like Nim exceptions. More details in language manual.

• nil for strings/seqs is finally gone. Instead the default value for these is "" / @[].

• Accessing the binary zero terminator in Nim's native strings is now invalid. Internally a Nim string still has the trailing zero for zero-copy interoperability with cstring. Compile your code with the new switch --laxStrings:on if you need a transition period.

• The command syntax now supports keyword arguments after the first comma.

• Thread-local variables can now be declared inside procs. This implies all the effects of the global pragma.

• Nim now supports except clause in the export statement.

• Range float types, example range[0.0 .. Inf]. More details in language manual.

Tool changes

• jsondoc2 has been renamed jsondoc, similar to how doc2 was renamed doc. The old jsondoc can still be invoked with jsondoc0.

Compiler changes

• The VM's instruction count limit was raised to 1 billion instructions in order to support more complex computations at compile-time.

• Support for hot code reloading has been implemented for the JavaScript target. To use it, compile your code with --hotCodeReloading:on and use a helper library such as LiveReload or BrowserSync.

• A new compiler option --cppCompileToNamespace puts the generated C++ code into the namespace "Nim" in order to avoid naming conflicts with existing C++ code. This is done for all Nim code - internal and exported.

• Added macros.getProjectPath and ospaths.putEnv procs to Nim's virtual machine.

• The deadCodeElim option is now always turned on and the switch has no effect anymore, but is recognized for backwards compatibility.

• experimental is now a pragma / command line switch that can enable specific language extensions, it is not an all-or-nothing switch anymore.

• Nintendo Switch was added as a new platform target. See the compiler user guide for more info.

Bugfixes