Language and Compiler Features Since Delphi 7

New Delphi language features since Delphi 7

By: Nick Hodges

Abstract: See many of the major new language features in Delphi released after the Delphi 7 version

Language and Compiler Features Since Delphi 7
Inlining	Routines can now be marked with the inline directive.  This tells the compiler that, instead of actually calling the routine, it should emit code that includes the routine at the call site.
Operator Overloading	Delphi allows certain functions, or operators, to be overloaded within record declarations TMyClass = operator Add(a, b: TMyClass): TMyClass; operator Subtract(a, b: TMyClass): TMyclass; operator Implicit(a: Integer): TMyClass; operator Implicit(a: TMyClass): Integer; operator Explicit(a: Double): TMyClass; ; TMyClass.Add(a, b: TMyClass): TMyClass; ... ; x, y: TMyClassbegin x := 12; y := x + x; b := b + 100; ;
Class Helpers	A class helper is a type that - when associated with another class - introduces additional method names and properties which may be used in the context of the associated class (or its descendants). Class helpers are a way to extend a class without using inheritance. A class helper simply introduces a wider scope for the compiler to use when resolving identifiers. When you declare a class helper, you state the helper name, and the name of the class you are going to extend with the helper. You can use the class helper any place where you can legally use the extended class. The compiler's resolution scope then becomes the original class, plus the class helper. Class helpers provide a way to extend a class, but they should not be viewed as a design tool to be used when developing new code. They should be used solely for their intended purpose, which is language and platform RTL binding. TMyClass = MyProc; MyFunc: Integer; ; ... TMyClass.MyProc; X: Integer; X := MyFunc; ; TMyClass.MyFunc: Integer; ... ; ... TMyClassHelper = helper TMyClass HelloWorld; MyFunc: Integer; ; ... TMyClassHelper.HelloWorld; WriteLn(Self.ClassName); ; TMyClassHelper.MyFunc: Integer; ... ; ... X: TMyClass; X := TMyClass.Create; X.MyProc; X.HelloWorld; X.MyFunc; ;
strict private	The private keyword actually creates a " friendship" relationship between classes in the same unit.  The strict private declaration creates a true private field, not viewable by any other class, not even classes in the same unit.
strict protected	Similar to the strict private declaration, strict protectedcreates a true protected member, visible only to the declaring class and its descendents.
Records with Methods	In addition to fields, records now may have properties and methods (including constructors), class properties, class methods, class fields, and nested types.  TMyRecord = TInnerColorType = Integer; Red: Integer; Blue: Integer; printRed(); Create(val: Integer); RedProperty: TInnerColorType Red Red; BlueProp: TInnerColorType Blue Blue; ; TMyRecord.Create(val: Integer); Red := val; ; TMyRecord.printRed; writeln(, Red); ;
class abstract	Classes, and not just methods, can be declared as abstract. TAbstractClass = SomeProcedure; ;
class sealed	Classes marked as sealed cannot be inherited from. TAbstractClass = sealed SomeProcedure; ;
class const	Classes can now have class constants -- a constant value associated with the class itself and not an instance of the class. TClassWithConstant = SomeConst = ; ; TForm1.FormCreate(Sender: TObject); ShowMessage(TClassWithConstant.SomeConst); ;
class type	A class can now contain a type declaration that is usable only within that class. TClassWithClassType = TRecordWithinAClass = SomeField: ; ; RecordWithinAClass: TRecordWithinAClass; ; ... TForm1.FormCreate(Sender: TObject); TClassWithClassType.RecordWithinAClass.SomeField := ; ShowMessage(TClassWithClassType.RecordWithinAClass.SomeField); ;
class var	A class can also have a class variable, applicable only to the class and not an instance of the class. See "class type" for an example.
class property	A class can have a class property, which is a property that applies only to the class reference and not to an instance of a class.  The accessors for the class property must be either class methods or class variables. See the example in "static class methods" below.
nested classes	Type declarations can be nested within class declarations. They present a way to keep conceptually related types together, and to avoid name collisions. TOuterClass = strict MyField: Integer; TInnerClass = MyInnerField: Integer; InnerProc; ; OuterProc; ; TOuterClass.TInnerClass.InnerProc; ... ;
final methods	A virtual method that you override can now be marked final, preventing derived classes from overriding that method. TAbstractClass = classabstract Bar; ; ; TSealedClass = classsealed(TAbstractClass) Bar; ; ; TFinalMethodClass = (TAbstractClass) Bar; ; ; ;
sealed methods	Classes marked as sealed cannot be descended from. See the example in 'final methods'.
static class methods	Classes can have static class methods -- i.e. methods that can be called from a class type. Class static methods can be accessed without an object reference. Unlike ordinary class methods, class static methods have no Self parameter at all. They also cannot access any instance members. (They still have access to class fields, class properties, and class methods.) Also unlike class methods, class static methods cannot be declared virtual. TMyClass = strict FX: Integer; strict GetX: Integer; ; SetX(val: Integer); ; X: Integer GetX SetX; StatProc(s: ); ; ; TMyClass.X := 17; TMyClass.StatProc();
for-in loop	Delphi 2007 for Win32 supports for-element-in-collection style iteration over containers. The following container iteration patterns are recognized by the compiler: Element ArrayExpr Stmt; Element StringExpr Stmt; Element SetExpr Stmt; Element CollectionExpr Stmt;

转载于:https://www.cnblogs.com/Phoenix-Rock/archive/2007/06/29/800350.html