1. Microsoft .NET
3. Language Innovations
Pan Wuming
2017

2. Topics Three New Languages Evolving From OO Paradigm
Towards Higher Order: Expressiveness
Towards Higher Order: Contract Enabled
Towards Higher Order: Enhanced Dynamics
Towards Higher Order: Compiling As Services
Three new languages: C#, IL and F#
Evolving from OO Paradigm
Everything is object
Members for Abstraction
Accessibility for Encapsulation
Inheritance and Polymorphism
Solving name confliction and multi-inheritance
Towards higher order: Expressiveness
Delegate
Lambda Expression
Generic
Attribute
LINQ
Compiler API
Effective coding
References：
Common Type System（MSDN）
.NET Framework Class Library Overview （MSDN）
Inheritance (C# Programming Guide) （MSDN）
Polymorphism (C# Programming Guide) （MSDN）

3. 1. Three New Languages C# IL F#

4. 2. Evolving from OO Paradigm
Solving OO Defects
Multi-inheritance
Name conflicts
Everything is object
Members
For
Abstraction
Accessibility
for
Encapsulation
Inheritance
And
Polymorphism

5. Everything is object Classes Structures
Enumerations
Interfaces
Delegates
An assembly is a collection of types
Each type is derived from Object Type
Five Categories of Types

6. Single Double Boolean Object String Primitive data types Integer
Byte
SByte
Int16
Int32
Int64
UInt16
UInt32
UInt64
Floating point
Single
Double
Value type =
Structure type Or
Enumeration type
Implicitly inherit from System.ValueType
all primitive data types are defined as structures
Logical
Boolean
Other
Char
Decimal
IntPtr
UIntPtr
Class objects
Object
String

7. Members for Abstraction
Fields
Properties
Events
Constructors
Methods
Nested types
Members for Abstraction

8. Accessibility for Encapsulation
Traditional OO Accessibility
Private
Protected
Public
.NET Accessibility
Internal
Protected Internal
Being Internal, a type or a member is accessible within the boundary of the assembly which contains it.

9. Inheritance and Polymorphism
reuse, extend, and modify the behavior of base classes.
Polymorphism
At run time, objects of a derived class may be treated as objects of a base.
Base classes may define and implement virtual methods, and derived classes can override them.

11. Solving name conflicts and multi-inheritance
A derived class can have only one direct base class.
A class or struct can implement multiple interfaces.
Explicit implementation is used to resolve name conflicts of two interfaces.
However, multi-inheritance without name conflict is a useful means for providing meaningful structure of a program.

13. 3. Towards higher order: Expressiveness
Delegate
Lambda Expression
Generic
LINQ
Extension method
Effective Coding

14. Lambda Expression

15. Effective coding: Examples
Indexers
Foreach loop
Partial Class
Nullable Type
Automatic implementation of Property
Array Initialization
Implicitly Typed
Named and Optional Arguments
Int? i=5;
Instances of the System.Nullable<T> struct
public string FirstName { get; set; } = "Jane";
int[] Numbers = { 0, 1, 2, 3, 4 };
var i = 1;
var hw = "Hello World!";

16. 4. Towards Higher Order: Contract Enabled
Attribute
Interact with other program
Interact with compiler
Example: Serialization
Example: Platform Invoke
Interact with CLR
Example: Caller Information

18. Common Uses for Attributes
Marking methods using the WebMethod attribute in Web services.
Describing how to marshal method parameters when interoperating with native code.
Describing the COM properties for classes, methods, and interfaces.
Calling unmanaged code using the DllImportAttribute class.
Describing your assembly in terms of title, version, description, or trademark.
Describing which members of a class to serialize for persistence.
Describing how to map between class members and XML nodes for XML serialization.
Describing the security requirements for methods.
Specifying characteristics used to enforce security.
Controlling optimizations by the just-in-time (JIT) compiler.
Obtaining information about the caller to a method.

19. 5. Towards Higher Order: Enhanced Dynamics
Type Class and Reflection
Dynamic Language Runtime
Dynamic languages can identify the type of an object at run time
The ability to use a rapid feedback loop (REPL, or read-evaluate-print loop).
Support for both top-down development and more traditional bottom-up development
Easier refactoring and code modifications
Dynamic languages make excellent scripting languages

20. Towards Higher Order: Compiling As Services
Compiler API
Scripting

22. See you next class
Layperson
Professional