Nim/changelog.md

v1.6.x - yyyy-mm-dd

Standard library additions and changes

• Make {.requiresInit.} pragma to work for distinct types.

• Added a macros enumLen for returning the number of items in an enum to the typetraits.nim module.

• prelude now works with the JavaScript target.

• Added almostEqual in math for comparing two float values using a machine epsilon.

• The JSON module can now handle integer literals and floating point literals of arbitrary length and precision. Numbers that do not fit the underlying BiggestInt or BiggestFloat fields are kept as string literals and one can use external BigNum libraries to handle these. The parseFloat family of functions also has now optional rawIntegers and rawFloats parameters that can be used to enforce that all integer or float literals remain in the "raw" string form so that client code can easily treat small and large numbers uniformly.

• Added an overload for the collect macro that inferes the container type based on the syntax of the last expression. Works with std seqs, tables and sets.

• Added randState template that exposes the default random number generator. Useful for library authors.

• Added std/enumutils module containing genEnumCaseStmt macro that generates case statement to parse string to enum.

• Removed deprecated iup module from stdlib, it has already moved to nimble.

• nodejs backend now supports osenv: getEnv, putEnv, envPairs, delEnv, existsEnv.

• doAssertRaises now correctly handles foreign exceptions.

• Added asyncdispatch.activeDescriptors that returns the number of currently active async event handles/file descriptors.

• --gc:orc is now 10% faster than previously for common workloads. If you have trouble with its changed behavior, compile with -d:nimOldOrc.

• os.FileInfo (returned by getFileInfo) now contains blockSize, determining preferred I/O block size for this file object.

• repr now doesn't insert trailing newline; previous behavior was very inconsistent, see #16034. Use -d:nimLegacyReprWithNewline for previous behavior.

• Added ** to jsffi.

• writeStackTrace is available in JS backend now.

• strscans.scanf now supports parsing single characters.

• strscans.scanTuple added which uses strscans.scanf internally, returning a tuple which can be unpacked for easier usage of scanf.

• Added setutils.toSet that can take any iterable and convert it to a built-in set, if the iterable yields a built-in settable type.

• Added math.isNaN.

• echo and debugEcho will now raise IOError if writing to stdout fails. Previous behavior silently ignored errors. See #16366. Use -d:nimLegacyEchoNoRaise for previous behavior.

• Added new operations for singly- and doubly linked lists: lists.toSinglyLinkedList and lists.toDoublyLinkedList convert from openArrays; lists.copy implements shallow copying; lists.add concatenates two lists - an O(1) variation that consumes its argument, addMoved, is also supplied.

Language changes

• nimscript now handles except Exception as e.

• The cstring doesn't support []= operator in JS backend.

• nil dereference is not allowed at compile time. cast[ptr int](nil)[] is rejected at compile time.

Compiler changes

• Added --declaredlocs to show symbol declaration location in messages.

• Source+Edit links now appear on top of every docgen'd page when nim doc --git.url:url ... is given.

• Added nim --eval:cmd to evaluate a command directly, see nim --help.

• VM now supports addr(mystring[ind]) (index + index assignment)

• Type mismatch errors now show more context, use -d:nimLegacyTypeMismatch for previous behavior.

Tool changes

• The rst parser now supports markdown table syntax. Known limitations:
  • cell alignment is not supported, i.e. alignment annotations in a delimiter row (:---, :--:, ---:) are ignored,
  • every table row must start with |, e.g. | cell 1 | cell 2 |.