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, assertions, formatfloat are about to move out of the system module. You may instead import std/syncio, std/assertions and std/formatfloat. 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 included in most JavaScript output files. Now, it is only included with -d:nimJsMathTruncPolyfill. 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.

• The {.this.} pragma, deprecated since 0.19, has been removed.

• nil is no longer a valid value for distinct pointer types.

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).
• The md5 module 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 uses and defaults 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 ISO 8601 week date utilities in times:
  • Added IsoWeekRange, a range type for weeks in a week-based year.
  • Added IsoYear, a distinct type for a week-based year in contrast to a regular year.
  • Added a initDateTime overload to create a datetime from an ISO week date.
  • Added getIsoWeekAndYear to get an ISO week number and week-based year from a datetime.
  • Added getIsoWeeksInYear to return the number of weeks in a 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 module parseopt2.
• Removed deprecated module sharedstrings.
• Removed deprecated module dom_extensions.
• Removed deprecated module LockFreeHash.
• Removed deprecated module events.
• 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/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.

• 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.

• Macro pragmas changes:

  • 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
    

• Redefining templates with the same signature implicitly was previously allowed to support certain macro code. A {.redefine.} pragma has been added to make this work explicitly, and a warning is generated in the case where it is implicit. This behavior only applies to templates, redefinition is generally disallowed for other symbols.

Compiler 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".)

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

• 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, --hintAsError and --warningAsError now only applies to the current package.

• The switch --nimMainPrefix:prefix has been added to add a prefix to the names of NimMain and related functions produced on the backend. This prevents conflicts with other Nim static libraries.

Tool changes

• 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.