泛型单元

文章来自：http://interactiveasp.net/blogs/spgilmore/archive/2009/12/23/using-generics-in-delphi.aspx

包含泛型的单元：Generics.Defaults, Generics.Collections, SysUtils.pas

Here are the public declarations in Generics.Defaults.pas:

Classes / Interfaces	Description
IComparer<T>	Implements a compare function returning less-than, greater-than or equal-to.
IEqualityComparer<T>	Implements a compare function returning equal-to or not.
TComparer<T>	Abstract class for implementing IComparer<T>.
TEqualityComparer<T>	Abstract class for implementing IEqualityComparer<T>
TSingletonImplementation	Weak-reference implementation of TInterfacedObject.  Instances are not automatically freed.
TDelegatedEqualityComparer<T>	A comparer that takes a delegated comparison function and uses it to determine equality.
TDelegatedComparer<T>	A comparer that takes a delegated function to do the actual comparison.
TCustomComparer<T>	An abstract singleton class for comparison operations.
TStringComparer	Compares strings.
Method prototypes / delegates
TComparison<T>	A delegate method prototype for less-than, greater-than, or equal-to comparisons.
TEqualityComparison<T>	A delegate method prototype for equality comparisons.
THasher<T>	A delegate method prototype for getting the hash value of an object or value.
Concrete Functions
function BobJenkinsHash(const Data; Len, InitData: Integer): Integer;	Returns a hash from the given data.
function BinaryCompare(const Left, Right: Pointer; Size: Integer): Integer;	A method to compare binary data.  Does not match comparison prototypes, so must be used from a comparison class rather than pass as a delegated method.

Here are the public declarations in Generics.Collections.pas:

Classes / Interfaces	Description
TArray	Contains no data, but provides methods for working with arrays.  Strangely, the class is not generic and the members are.  This can easily be confused with TArray<T>, which is in System.pas, which contains data and no methods.
TEnumerator<T>	Implements the iterator pattern on your data.
TEnumerable<T>	Returns an enumerator, allowing your class to be used in a For..In construct.
TList<T>	A generic collection or objects, records or primitives.
TQueue<T>	A generic queue (first in / last out) collection.
TStack<T>	A generic stack (first in / first out) collection.
TPair<TKey, TValue>	A structure containing two child members of disparate types.
TDictionary<TKey, TValue>	A searchable collection with lookup keys.
TObjectList<T: class>	A generic collection of objects (records and primitives not allowed).
TObjectQueue<T: class>	A generic queue of objects.
TObjectStack<T: class>	A generic stack of objects.
TObjectDictionary<TKey, TValue>	A generic collection of owned objects with lookup keys.
Enums
TCollectionNotification	Used in TCollectionNotifyEvent<>
TDictionaryOwnerships	Used by TObjectDictionary<>
Method prototypes / delegates
TCollectionNotifyEvent<T>	Used by various collections to implement an observer pattern.
Concrete functions
InCircularRange
Type aliases
PObject	Pointer to TObject.
Exceptions
ENotsupportedException

Here are the pertinent declarations in SysUtils.pas:

Method prototypes / delegates	Description
TProc	A procedure with no parameters.
TProc<T>	A procedure with one generic parameter.
TProc<T1, T2>	A procedure with two generic parameters.
TProc<T1, T2, T3>	A procedure with three generic parameters.
TProc<T1, T2, T3, T4>	A procedure with four generic parameters.
TFunc<TResult>	A function with no parameters and a generic return type.
TFunc<T, TResult>	A function with one generic parameter and a generic return type.
TFunc<T1, T2, TResult>	A function with two generic parameters and a generic return type.
TFunc<T1, T2, T3, TResult>	A function with three generic parameters and a generic return type.
TFunc<T1, T2, T3, T4, TResult>	A function with four generic parameters and a generic return type.
TPredicate<T>	A function with one generic parameter and a boolean return type.  This is used by collections as a “filter” for elements.  Elements that are passed to a predicate function which return false are excluded from the result.