370
个编辑
更改
跳到导航
跳到搜索
第185行：
第185行： − 协归纳数据定义是一种规定了可以对一段数据进行操作的定义；;通常，自引用的协归纳定义用于无限大小的数据结构。+ + 第191行：
第192行： − 非正式给出的无限串流的共归纳定义可能是这样的。+ 第198行：
第199行： − 头是字符串，而尾是字符串流。 + + − 这与字符串列表的归纳定义非常相似；不同的是，这个定义指定了如何访问数据结构的内容，即通过访问函数 的头和尾以及这些内容可能是什么，而归纳定义则指定了如何创建结构以及它可能是由什么创建的。+ + 第208行：
第211行： − Corecursion与共归纳相关，可以用来计算（可能）无限对象的特定实例。作为一种编程技术，它最常被用于惰性编程语言中，当程序输出的期望大小或精度未知时，它可以优于递归。在这种情况下，程序既需要一个无限大（或无限精确）结果的定义，又需要一个取该结果有限部分的机制。计算前n个质数的问题是一个可以用一个核心递归程序来解决的问题（例如这里）。+
→协归纳定义的数据和共递归
A coinductive data definition is one that specifies the operations that may be performed on a piece of data; typically, self-referential coinductive definitions are used for data structures of infinite size.
A coinductive data definition is one that specifies the operations that may be performed on a piece of data; typically, self-referential coinductive definitions are used for data structures of infinite size.
协归纳数据定义规定了可以对一段数据进行怎样的操作；通常，自引用的协归纳定义可以用于定义无限大小的数据结构。
A coinductive definition of infinite [[stream (computer science)|streams]] of strings, given informally, might look like this:
A coinductive definition of infinite [[stream (computer science)|streams]] of strings, given informally, might look like this:
A coinductive definition of infinite streams of strings, given informally, might look like this:
A coinductive definition of infinite streams of strings, given informally, might look like this:
用共归纳定义法来定义无限大小的字符串流，一个可能的例子是这样的：
A stream of strings is an object s such that:
A stream of strings is an object s such that:
字符串流是s这样的对象：
字符串流是s这样的对象：
头部<code>head</code>是字符串，且
尾部<code>tail</code>是字符串流。
This is very similar to an inductive definition of lists of strings; the difference is that this definition specifies how to access the contents of the data structure—namely, via the [[accessor]] functions <code>head</code> and <code>tail</code>—and what those contents may be, whereas the inductive definition specifies how to create the structure and what it may be created from.
This is very similar to an inductive definition of lists of strings; the difference is that this definition specifies how to access the contents of the data structure—namely, via the [[accessor]] functions <code>head</code> and <code>tail</code>—and what those contents may be, whereas the inductive definition specifies how to create the structure and what it may be created from.
这与字符串列表的归纳定义非常相似；不同的是，这个定义指定了如何访问数据结构的内容，即通过访问函数的头<code>head</code>和尾<code>tail</code>以及这些内容可能是什么，而归纳定义则指定了如何创建结构以及它可能是由什么创建的。
Corecursion is related to coinduction, and can be used to compute particular instances of (possibly) infinite objects. As a programming technique, it is used most often in the context of [[lazy evaluation|lazy]] programming languages, and can be preferable to recursion when the desired size or precision of a program's output is unknown. In such cases the program requires both a definition for an infinitely large (or infinitely precise) result, and a mechanism for taking a finite portion of that result. The problem of computing the first n [[prime numbers]] is one that can be solved with a corecursive program (e.g. [[Fold (higher-order function)#Examples|here]]).
Corecursion is related to coinduction, and can be used to compute particular instances of (possibly) infinite objects. As a programming technique, it is used most often in the context of [[lazy evaluation|lazy]] programming languages, and can be preferable to recursion when the desired size or precision of a program's output is unknown. In such cases the program requires both a definition for an infinitely large (or infinitely precise) result, and a mechanism for taking a finite portion of that result. The problem of computing the first n [[prime numbers]] is one that can be solved with a corecursive program (e.g. [[Fold (higher-order function)#Examples|here]]).
Corecursion is related to coinduction, and can be used to compute particular instances of (possibly) infinite objects. As a programming technique, it is used most often in the context of lazy programming languages, and can be preferable to recursion when the desired size or precision of a program's output is unknown. In such cases the program requires both a definition for an infinitely large (or infinitely precise) result, and a mechanism for taking a finite portion of that result. The problem of computing the first n prime numbers is one that can be solved with a corecursive program (e.g. here).
Corecursion is related to coinduction, and can be used to compute particular instances of (possibly) infinite objects. As a programming technique, it is used most often in the context of lazy programming languages, and can be preferable to recursion when the desired size or precision of a program's output is unknown. In such cases the program requires both a definition for an infinitely large (or infinitely precise) result, and a mechanism for taking a finite portion of that result. The problem of computing the first n prime numbers is one that can be solved with a corecursive program (e.g. here).
共递归与协归纳相关，可以用来计算无限规模的对象。作为一种编程技术，它最常被用于 '''<font color="#f668800">惰性编程语言 lazy programming language</font>'''中，当程序输出的大小或精度未知时，使用共递归会比递归更合适。在这种情况下，程序既需要一个无限大（或无限精确）结果的定义，又需要一个取该结果有限部分的机制。计算出前n个质数的问题，就是能用一个核心递归程序来解决的问题。
==Types of recursion==
==Types of recursion==