Algebraic data types are a concise representation of types permitted in some functional languages as StandardML and Haskell. They can also be defined in Scala, and although their definition is more cumbersome,
data Human = Worker String String | Student String String 1. 两者语法有差异,但实际上非常神似: Haskell 中的 Worker 和 Student 都是 value constructor,则 Scala 中的 Worker 和 Student 也是 constuctor; Haskell 中定义的类型是 Huma...
data Type t = RInt | RChar | RList (Type t) | RPair (Type t) (Type t) 以上,参数t从未被使用。它实际上是虚假的。 这意味着,例如: RInt :: Type a 对于任何类型a。相比之下,如果遵循with约束,则不可能为除t ~ Int之外的任何t创建RInt :: Type t。
Practical Dependent Types in Haskell: Type-Safe Neural Networks, Le (2016) A guide to convolutional arithmetic for deep learning, Dumoulin and Visin (2018) Type systems Generalized Algebraic Data Types and Object-Oriented Programming, Kennedy and Russo (2005) Java Generics are Turing Complete, Grigo...
ADTs offer a simple way to define a type which isone of a set of possible cases, and allowing data to be associated with each case and packed/unpacked along with it. Examples in other programming languages Algebraic data types are very common in functional programming languages, likeHaskellor...
generic, whenever we define a monoid in, say, Haskell or Scala, we define it in terms of a type parameter, we call it parametric polymorphism. The type monoid - the algebra of monoid is defined in terms of a polymorphic type say A. We don’t have any constraint on what this A has...
dataGoats=Goats Intderiving(Eq,Show) Product types Product types 类似于 C 语言的结构体,它就像用多个类型的值来表达一个单独的数据结构。元组就是一个 Product types (,)::a->b->(a,b) Record syntax Records是 Haskell 提供给 product types 的一个额外的语法 ...
Modern programming languages as Kotlin or Rust have advanced features to statically ensure data and memory safety, like nullable and ownership types. Other languages like C, Erlang, Go, Haskell, Java, or Scala, have static analysis tools to help the developer detect at compile-time...
The laws are written in a comment to the class definition. Gofer, Haskell and most other functional languages do not allow laws to be defined in the language. This is a pity, because even if the implementation wouldn’t check the validity of ...
Data typesin Haskell It is possible to represent such algebraic data types using subclasses: the parent class is the "enumeration" type, and each child class represents a case of the enumeration with it's associated parameters. This will however either require you to spread out your business lo...