patterns

General Patterns

active record
mvc
mvvm
state machine
reference couting
COW(Copy On Write)
iterator
組合子邏輯
柯里化（英語：Currying）
λ演算
monod
Curiously recurring template pattern (CRTP)
https://en.wikipedia.org/wiki/Double-chance_function
SOLID设计原则
https://en.wikipedia.org/wiki/GRASP_(object-oriented_design)

并發相關

active object
actor model
blockingQueue
1. take
2. put
ForkJoinPool
1. execute
future, promise, delay, deferred
proactor
reactor
flow-graph
https://en.wikipedia.org/wiki/Algorithmic_skeleton

GOF

GoF: ref ref ref_cn ref
Creational
1. Simple Factory
2. Factory Method
3. Abstract Factory
4. Builder
5. Prototype
6. Singleton
7. 2.1Builder
8. 2.2Factory
9. 2.3Abstract Factory
10. 2.4Prototype
11. 2.5Singleton
1. Structural
2. Behavioral

Creational patterns[edit]

Name	Description	In Design Patterns	In Code Complete[13]	Other
Abstract factory	Provide an interface for creating families of related or dependent objects without specifying their concrete classes.	Yes	Yes	N/A
Builder	Separate the construction of a complex object from its representation, allowing the same construction process to create various representations.	Yes	No	N/A
Dependency Injection	A class accepts the objects it requires from an injector instead of creating the objects directly.	No	No	N/A
Factory method	Define an interface for creating a single object, but let subclasses decide which class to instantiate. Factory Method lets a class defer instantiation to subclasses.	Yes	Yes	N/A
Lazy initialization	Tactic of delaying the creation of an object, the calculation of a value, or some other expensive process until the first time it is needed. This pattern appears in the GoF catalog as "virtual proxy", an implementation strategy for the Proxy pattern.	No	No	PoEAA[14]
Multiton	Ensure a class has only named instances, and provide a global point of access to them.	No	No	N/A
Object pool	Avoid expensive acquisition and release of resources by recycling objects that are no longer in use. Can be considered a generalisation of connection pool and thread pool patterns.	No	No	N/A
Prototype	Specify the kinds of objects to create using a prototypical instance, and create new objects from the 'skeleton' of an existing object, thus boosting performance and keeping memory footprints to a minimum.	Yes	No	N/A
Resource acquisition is initialization (RAII)	Ensure that resources are properly released by tying them to the lifespan of suitable objects.	No	No	N/A
Singleton	Ensure a class has only one instance, and provide a global point of access to it.	Yes	Yes	N/A

Structural patterns[edit]

Name	Description	In Design Patterns	In Code Complete[13]	Other
Adapter, Wrapper, or Translator	Convert the interface of a class into another interface clients expect. An adapter lets classes work together that could not otherwise because of incompatible interfaces. The enterprise integration pattern equivalent is the translator.	Yes	Yes	N/A
Bridge	Decouple an abstraction from its implementation allowing the two to vary independently.	Yes	Yes	N/A
Composite	Compose objects into tree structures to represent part-whole hierarchies. Composite lets clients treat individual objects and compositions of objects uniformly.	Yes	Yes	N/A
Decorator	Attach additional responsibilities to an object dynamically keeping the same interface. Decorators provide a flexible alternative to subclassing for extending functionality.	Yes	Yes	N/A
Extension object	Adding functionality to a hierarchy without changing the hierarchy.	No	No	Agile Software Development, Principles, Patterns, and Practices[15]
Facade	Provide a unified interface to a set of interfaces in a subsystem. Facade defines a higher-level interface that makes the subsystem easier to use.	Yes	Yes	N/A
Flyweight	Use sharing to support large numbers of similar objects efficiently.	Yes	No	N/A
Front controller	The pattern relates to the design of Web applications. It provides a centralized entry point for handling requests.	No	No	J2EE Patterns[16] PoEAA[17]
Marker	Empty interface to associate metadata with a class.	No	No	Effective Java[18]
Module	Group several related elements, such as classes, singletons, methods, globally used, into a single conceptual entity.	No	No	N/A
Proxy	Provide a surrogate or placeholder for another object to control access to it.	Yes	No	N/A
Twin [19]	Twin allows modeling of multiple inheritance in programming languages that do not support this feature.	No	No	N/A

Behavioral patterns[edit]

Name	Description	In Design Patterns	In Code Complete[13]	Other
Blackboard	Artificial intelligence pattern for combining disparate sources of data (see blackboard system)	No	No	N/A
Chain of responsibility	Avoid coupling the sender of a request to its receiver by giving more than one object a chance to handle the request. Chain the receiving objects and pass the request along the chain until an object handles it.	Yes	No	N/A
Command	Encapsulate a request as an object, thereby allowing for the parameterization of clients with different requests, and the queuing or logging of requests. It also allows for the support of undoable operations.	Yes	No	N/A
Interpreter	Given a language, define a representation for its grammar along with an interpreter that uses the representation to interpret sentences in the language.	Yes	No	N/A
Iterator	Provide a way to access the elements of an aggregate object sequentially without exposing its underlying representation.	Yes	Yes	N/A
Mediator	Define an object that encapsulates how a set of objects interact. Mediator promotes loose coupling by keeping objects from referring to each other explicitly, and it allows their interaction to vary independently.	Yes	No	N/A
Memento	Without violating encapsulation, capture and externalize an object's internal state allowing the object to be restored to this state later.	Yes	No	N/A
Null object	Avoid null references by providing a default object.	No	No	N/A
Observer or Publish/subscribe	Define a one-to-many dependency between objects where a state change in one object results in all its dependents being notified and updated automatically.	Yes	Yes	N/A
Servant	Define common functionality for a group of classes. The servant pattern is also frequently called helper class or utility class implementation for a given set of classes. The helper classes generally have no objects hence they have all static methods that act upon different kinds of class objects.	No	No	N/A
Specification	Recombinable business logic in a Boolean fashion.	No	No	N/A
State	Allow an object to alter its behavior when its internal state changes. The object will appear to change its class.	Yes	No	N/A
Strategy	Define a family of algorithms, encapsulate each one, and make them interchangeable. Strategy lets the algorithm vary independently from clients that use it.	Yes	Yes	N/A
Template method	Define the skeleton of an algorithm in an operation, deferring some steps to subclasses. Template method lets subclasses redefine certain steps of an algorithm without changing the algorithm's structure.	Yes	Yes	N/A
Visitor	Represent an operation to be performed on the elements of an object structure. Visitor lets a new operation be defined without changing the classes of the elements on which it operates.	Yes	No	N/A

Concurrency patterns[edit]

Name	Description	In POSA2[20]	Other
Active Object	Decouples method execution from method invocation that reside in their own thread of control. The goal is to introduce concurrency, by using asynchronous method invocation and a scheduler for handling requests.	Yes	N/A
Balking	Only execute an action on an object when the object is in a particular state.	No	N/A
Binding properties	Combining multiple observers to force properties in different objects to be synchronized or coordinated in some way.[21]	No	N/A
Compute kernel	The same calculation many times in parallel, differing by integer parameters used with non-branching pointer math into shared arrays, such as GPU-optimized Matrix multiplication or Convolutional neural network.	No	N/A
Double-checked locking	Reduce the overhead of acquiring a lock by first testing the locking criterion (the 'lock hint') in an unsafe manner; only if that succeeds does the actual locking logic proceed.Can be unsafe when implemented in some language/hardware combinations. It can therefore sometimes be considered an anti-pattern.	Yes	N/A
Event-based asynchronous	Addresses problems with the asynchronous pattern that occur in multithreaded programs.[22]	No	N/A
Guarded suspension	Manages operations that require both a lock to be acquired and a precondition to be satisfied before the operation can be executed.	No	N/A
Join	Join-pattern provides a way to write concurrent, parallel and distributed programs by message passing. Compared to the use of threads and locks, this is a high-level programming model.	No	N/A
Lock	One thread puts a "lock" on a resource, preventing other threads from accessing or modifying it.[23]	No	PoEAA[14]
Messaging design pattern (MDP)	Allows the interchange of information (i.e. messages) between components and applications.	No	N/A
Monitor object	An object whose methods are subject to mutual exclusion, thus preventing multiple objects from erroneously trying to use it at the same time.	Yes	N/A
Reactor	A reactor object provides an asynchronous interface to resources that must be handled synchronously.	Yes	N/A
Read-write lock	Allows concurrent read access to an object, but requires exclusive access for write operations.	No	N/A
Scheduler	Explicitly control when threads may execute single-threaded code.	No	N/A
Thread pool	A number of threads are created to perform a number of tasks, which are usually organized in a queue. Typically, there are many more tasks than threads. Can be considered a special case of the object pool pattern.	No	N/A
Thread-specific storage	Static or "global" memory local to a thread.	Yes	N/A

C++

Modern C++ patterns ref
1. RAII everywhere, so everything that holds a resource is an object that uses RAII. If you find a new/delete at all, then it’s in the same place.
2. Plain functions instead of factories, singletons etc.
3. Inheritance not more than 1 layer deep and from mostly abstract base classes only (except for simple “helper” methods)
4. Composition over inheritance
5. Think if inheritance and polymorphism is really able to completely abstract the implementations you need. Not rarely you’ll find the abstraction to be leaky and at some point you’ll have to find out, which subclass the thing you have is - at runtime. Or one of the subclass can not reasonable implement one of methods. This then often ends up with methods returning dummy values, null, throwing an “operation not supported” exception or something similar
6. Avoid “function pointer/lambda/polymorphism-magic” as much as possible. In most cases when I see a function/method-call I would like to know what it actually calls at compile-time, not at run-time 這個不是很贊同，因爲DI(Dependency Injection)是一個公認的decouple的手段。函數指針會使抽象程度增加，但這是爲了封裝和維護性
7. “Immutability as the default” is something I still struggle with, but try to adopt for future code I write
8. If immutability is not an option, data structures where data is only added but never removed also helps
Lazy evaluation
Recursion, List Manipulation, and Lazy Evaluation
Basic:
- RTTI
- Virtual functions
- shared_ptr etc
- Templates
- Virtual inheriting
- Variadic macros
Also useful:
- Attributes (it depends on your compiler)
- Variadic templates
- Variadic functions
- Constexpr (sorting in compile time / calculating hash of strings etc... but the latter is related to the last section)
- Lambdas
Useful for brainfucking or in special cases:
- CRTP
- SFINAE
- inable_if (type traits)
- Foreach macro
- User-defined literals

More C++ Idioms

ref CN

Advanced idioms[edit]

These are some more advanced C++ idioms.

Envelope Letter TODO

Deprecated idioms[edit]

Const auto_ptr

Haskell

https://zh.m.wikibooks.org/wiki/Haskell

Rust

Rust patterns ref
1. Constructor
2. Concatenating strings with format!
3. Privacy for extensibility
4. TODO stability for extensibility
5. TODO trait to separate visibility of methods from visibility of data (https://github.com/sfackler/rust-postgres/blob/master/src/lib.rs#L1400)
6. Collections are smart pointers
7. TODO leak amplification ("Vec::drain sets the Vec's len to 0 prematurely so that mem::forgetting Drain "only" mem::forgets more stuff. instead of exposing uninitialized memory or having to update the len on every iteration")
8. Finalisation in destructors
9. TODO interior mutability - UnsafeCell, Cell, RefCell
10. Iterating over an Option
11. Default trait
12. Pass variables to closure
13. mem::replace(_) to avoid needless clones
14. Temporary mutability
15. Builder
16. RAII guards
17. Newtype
18. TODO iterators (to safely avoid bounds checks)
19. TODO closures and lifetimes (coupling to lifetime)
20. TODO platform-specific sub-modules (https://github.com/rust-lang/rfcs/blob/master/text/0517-io-os-reform.md#platform-specific-opt-in)
21. Entry API (Currently just a boilerplate)
22. Visitor
23. Fold
24. Prefer small crates
25. Contain unsafety in small modules
26. TODO extension traits
27. TODO destructor bombs (ensure linear typing dynamically, e.g., https://github.com/Munksgaard/session-types/commit/0f25ccb7c3bc9f65fa8eaf538233e8fe344a189a)
28. TODO convertible to Foo trait for more generic generics (e.g., http://static.rust-lang.org/doc/master/std/fs/struct.File.html#method.open)
29. Late bound bounds (Currently just a boilerplate)
30. TODO 'shadow' borrowed version of struct - e.g., double buffering, Niko's parser generator
31. TODO composition of structs to please the borrow checker
32. TODO Error traits and Result forwarding
33. TODO graphs
34. Compose structs together for better borrowing
35. FFI patterns
Anti-patterns
1. TODO thread + catch_panic for exceptions
2. TODO Clone to satisfy the borrow checker
3. Deref polymorphism
4. TODO Matching all fields of a struct (back compat)
5. TODO wildcard matches
6. TODO taking an enum rather than having multiple functions
7. TODO unwrap()ing every Result instead of forwarding it
8. #[deny(warnings)]

Architecture pattern

Sub-domain area	Architecture pattern	Software design patterns	Solution patterns	Related patterns
Data integration/SOA	ETL (data extraction transformation and loading)	Change data captureNear real-time ETLBatch ETLData discovery	Error handling Job scheduling Data validation Slowly changing dimensions load	EAIMaster data hubOperational data store (ODS)Data mart Data warehouse
MFT
EAI/ESB	Publish/subscribe Request/reply Message exchange patterns	One-waySynchronous request/responseBasic callbackClaim check	SOA
Data architecture	Transaction data stores (TDS/OLTP)Master data store Operational data store Data mart Data warehouse	Custom applications databasesPackaged application databases		ETLEAISOA
Analytics and business intelligence	Transactional reportingOperational analyticsBusiness analyticsPredictive analyticsPrescriptive analyticsStreaming analyticsData science and advanced analyticsNLP	Transactional reporting data accessOperational reporting data accessAnalytical reporting data accessAnalytical dashboard data accessOperational dashboard data accessData mining	Real-time dashboardsIn-memory analyticsStatistical analysisPredictive analytics	ETLEAITDSOperational data storeData mart
Master data management	Master data hub	Master data replicationMaster data servicesMaster data synchronization		Change data captureEAISTD
Data modeling	Dimensional data modeling E-R data modeling	Modeling standardsNaming conventions
Artificial intelligence	Decision managementSpeech recognitionText analytics and NLPNatural language generationClassic machine learningDeep learningRobotic process automationImage and video analysis