Nim/changelog.md

v1.8.x - yyyy-mm-dd

Changes affecting backward compatibility

• 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.

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

Standard library additions and changes

• macros.parseExpr and macros.parseStmt now accept an optional filename argument for more informative errors.

std/smtp

• Sends ehlo first. If the mail server does not understand, it sends helo as a fallback.

Language changes

• 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
  

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

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.

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".)