[VS2008] VB9 の言語仕様書 (beta2)

…が公開されています。 って、 英語版だけですけど f(^^;

Visual Basic Language Specification 9.0 (Beta 2)

File Name: Visual Basic Language Specification 9.0.doc
Version: 9.0
Date Published: 10/17/2007
Language: English

※ ( 2007/12/20 追記 ) 12/19 付けで、 beta が取れたバージョンに変わっています。 ( URL は同じ。 )

ちらっと覗いてみると。

#Const DebugCode = True
#If DebugCode Then
    Console.WriteLine("about to print value")
#End If

…だとか、

Sub Main()
    Dim x?, y As Integer
    Dim a?, b As Long
    a = If(x, a) ' Result type: Long?
    y = If(x, 0)  ' Result type: Integer
End Sub

…だとか、 もはや BASIC ( Beginner's All purpose Symbolic Instruction Code ) じゃねぇ～! (w
って叫びたくなるようなものが f(^^;

これなんか…

Class MyBool
  Public Shared Widening Operator CType(b As Boolean) As MyBool
    '...
  End Operator
  Public Shared Narrowing Operator CType(b As MyBool) As Boolean
    '...
  End Operator
  Public Shared Operator IsTrue(b As MyBool) As Boolean
    '...
  End Operator
  Public Shared Operator IsFalse(b As MyBool) As Boolean
    '...
  End Operator
End Class

…は、 普段 C# で書いてる人でも、 いきなり見せられたら、 なんだかワカンナイかも。 f(^^;;;

ドキュメントから、 変更点のまとめを引用しておきます。

14.3 Version 8.0 (2nd Edition) to Version 9.0
This update covers the language changes made between version 8.0 of the language and version 9.0 of the language.

14.3.1 Major Changes

• Added extension methods.
• Added partial methods.
• Added member initialization to object creation expressions.
• Added local type inferencing.
• Added anonymous type construction.
• Added lambda expressions and closures.
• Added expression trees.
• Allowed delegate-creation expressions to create delegates over signatures that do not exactly match.
• Added nullable value types.
• Added the conditional operator.
• Added query expressions.

14.3.2 Minor Changes

• Added a section clarifying the role of native conversions.
• The language now takes into account the InternalsVisibleToAttribute attribute.
• Group classes can now collect from multiple types, including generic types.
• The members of Object are available on instances of interfaces, but are implicitly shadowed by the interfaces’ members.
• Delegate types can now be compared for specificity based on return types in overload resolution.
• Type arguments, whether inferred or not, must satisfy constraints for a method to be applicable in overload resolution.
• Type argument inference is extended to allow multiple inferences for a type argument to be resolved.
• Type arguments can be inferred from the return type of an AddressOf expression.