Nim/changelog.md

v1.8.x - yyyy-mm-dd

Changes affecting backward compatibility

• addr is now available for all addressable locations, unsafeAddr is now deprecated and an alias for addr.

• io and assertions are about to move out of the system module. You may instead import std/syncio and std/assertions. The -d:nimPreviewSlimSystem option makes these imports required.

• The gc:v2 option is removed.

• The threads:on option is now the default.

• Optional parameters in combination with : body syntax (RFC #405) are now opt-in via experimental:flexibleOptionalParams.

• The Math.trunc polyfill for targeting Internet Explorer was previously emitted for every JavaScript output file except if the symbol nodejs was defined via -d:nodejs. Now, it is only emitted if the symbol nimJsMathTruncPolyfill is defined. If you are targeting Internet Explorer, you may choose to enable this option or define your own Math.trunc polyfill using the emit pragma. Nim uses Math.trunc for the division and modulo operators for integers.

• shallowCopy is removed for ARC/ORC. Use move when possible or combine assignment and sink for optimization purposes.

• nimPreviewDotLikeOps is going to be removed or deprecated.

Standard library additions and changes

• macros.parseExpr and macros.parseStmt now accept an optional filename argument for more informative errors.
• Module colors expanded with missing colors from the CSS color standard. colPaleVioletRed and colMediumPurple have also been changed to match the CSS color standard.
• Fixed lists.SinglyLinkedList being broken after removing the last node (#19353).
• md5 now works at compile time and in JavaScript.
• std/smtp sends ehlo first. If the mail server does not understand, it sends helo as a fallback.
• Changed mimedb to use an OrderedTable instead of OrderedTableRef to support const tables.
• strutils.find now use and default to last=-1 for whole string searches, making limiting it to just the first char (last=0) valid.
• random.rand now works with Ordinals.

• Added times.IsoWeekRange, a range type to represent the number of weeks in an ISO week-based year.
• Added times.IsoYear, a distinct int type to prevent bugs from confusing the week-based year and the regular year.
• Added times.initDateTime to create a datetime from a weekday, and ISO 8601 week number and week-based year.
• Added times.getIsoWeekAndYear to get an ISO week number along with the corresponding ISO week-based year from a datetime.
• Added times.getIsoWeeksInYear to return the number of weeks in an ISO week-based year.
• Added std/oserrors for OS error reporting. Added std/envvars for environment variables handling.
• Added sep parameter in std/uri to specify the query separator.
• Added bindings to Array.shift and queueMicrotask in jscore for JavaScript targets.
• Added UppercaseLetters, LowercaseLetters, PunctuationChars, PrintableChars sets to std/strutils.

• Deprecated selfExe for Nimscript.
• Deprecated std/sums.

• Removed deprecated std/sharedstrings.
• Removed deprecated oids.oidToString.
• Removed define nimExperimentalAsyncjsThen for std/asyncjs.then and std/jsfetch.
• Removed deprecated jsre.test and jsre.toString.
• Removed deprecated math.c_frexp.
• Removed deprecated httpcore.`==`.
• Removed deprecated std/dom_extensions.
• Removed deprecated std/posix.CMSG_SPACE and std/posix.CMSG_LEN that takes wrong argument types.
• Removed deprecated osproc.poDemon, symbol with typo.

Language changes

• Tag tracking supports the definition of forbidden tags by the .forbids pragma which can be used to disable certain effects in proc types.

• Case statement macros are no longer experimental, meaning you no longer need to enable the experimental switch caseStmtMacros to use them.

• Templates now accept macro pragmas.

• Macro pragmas for var/let/const sections have been redesigned in a way that works similarly to routine macro pragmas. The new behavior is documented in the experimental manual.

• Pragma macros on type definitions can now return nnkTypeSection nodes as well as nnkTypeDef, allowing multiple type definitions to be injected in place of the original type definition.

  import macros
  
  macro multiply(amount: static int, s: untyped): untyped =
    let name = $s[0].basename
    result = newNimNode(nnkTypeSection)
    for i in 1 .. amount:
      result.add(newTree(nnkTypeDef, ident(name & $i), s[1], s[2]))
  
  type
    Foo = object
    Bar {.multiply: 3.} = object
      x, y, z: int
    Baz = object
  
  # becomes
  
  type
    Foo = object
    Bar1 = object
      x, y, z: int
    Bar2 = object
      x, y, z: int
    Bar3 = object
      x, y, z: int
    Baz = object
  

• Full command syntax and block arguments i.e. foo a, b: c are now allowed for the right-hand side of type definitions in type sections. Previously they would error with "invalid indentation".

• defined now accepts identifiers separated by dots, i.e. defined(a.b.c). In the command line, this is defined as -d:a.b.c. Older versions can use accents as in defined(`a.b.c`) to access such defines.

• Defines the gcRefc symbol which allows writing specific code for the refc GC.

Compiler changes

• nim can now compile version 1.4.0 as follows: nim c --lib:lib --stylecheck:off compiler/nim, without requiring -d:nimVersion140 which is now a noop.

• --styleCheck now only applies to the current package.

Tool changes

• The gc switch has been renamed to mm ("memory management") in order to reflect the reality better. (Nim moved away from all techniques based on "tracing".)

• Nim now supports Nimble version 0.14 which added support for lock-files. This is done by a simple configuration change setting that you can do yourself too. In $nim/config/nim.cfg replace pkgs by pkgs2.

• There is a new switch --nimMainPrefix:prefix to influence the NimMain that the compiler produces. This is particularly useful for generating static libraries.