xslt的优雅示例? [英] Elegant examples of xslt?

问题描述

在通过XAML进行了漫长的学习循环之后，我回到了HTML和javascript，并意识到声明性代码的概念(就转换规则而言)是一个非常强大的概念.

After a long learning loop via XAML, I've returned to HTML and javascript, and realised that the concept of declarative code - in terms of rules for transformation - is an incredibly powerful concept.

尽管XSLT语法过多，但XML的处理却是声明式转换编程的基石.但是，我总是很难理解如何将XSLT用于日常任务(使用XML).

Despite its surfeit of syntax, XSLT processing of XML is the keystone of declarative transformation programming. I have, however, always found it hard to understand how XSLT would be used for everyday tasks (with XML).

除了生成HTML之外，XSLT还可以通过哪些优雅的示例很好地解决编程问题?

What are some good examples of XSLT elegantly solving a programming problem, outside of generating HTML?

我猜它擅长于图形转换和数据重新处理...

I'm guessing it's good at graph transformation and data reprocessing...

我希望有一些实际的例子-使我无法使用完整的xslt的原因之一是代码的视觉复杂性.

I'm hoping for some actual examples - one of the things that puts me off full-on xslt is the visual complexity of the code.

推荐答案

人们经常可以找到漂亮的XSLT代码示例，尤其是当XSLT用作功能性编程语言时.

有关示例，请参见 此> FXSL 2.0 上的文章 -函数式编程XSLT 2.0的库.

For examples see this article on FXSL 2.0 -- the Functional Programming library for XSLT 2.0.

作为FP语言，XSLT也是 声明性语言 .除其他外，这意味着一个人声明了现有的关系.

As an FP language XSLT is also a declarative language. This, among other things means that one declares, specifies existing relationships.

这样的定义通常不需要任何其他代码即可产生结果-它本身是其自己的实现或可执行的定义或可执行的规范.

这是一个小例子.

此XPath 2.0表达式定义了"最大 Prime Factor 的自然数:

This XPath 2.0 expression defines the "Maximum Prime Factor of a natural number":

if(f:isPrime($pNum))
  then $pNum
  else
    for $vEnd in xs:integer(floor(f:sqrt($pNum, 0.1E0))),
        $vDiv1 in (2 to $vEnd)[$pNum mod . = 0][1],
        $vDiv2 in $pNum idiv $vDiv1
      return
        max((f:maxPrimeFactor($vDiv1),f:maxPrimeFactor($vDiv2)))

要用英语发音，如果 pNum 为质数，否则，如果 vDiv1 和 vDiv2 是 pNum 的两个因数，则最大质数为 pNum 是 vDiv1 和 vDiv2 的最大素数中的较大者.

To pronounce it in English, the maximum prime factor of a number pNum is the number itself, if pNum is prime, otherwise if vDiv1 and vDiv2 are two factors of pNum, then the maximum prime factor of pNum is the bigger of the maximum prime factors of vDiv1 and vDiv2.

我们如何使用它来实际计算 XSLT中的最大素数? 我们只需将上面的定义包裹在一个<xsl:function>中，然后得到结果！

How do we use this to actually calculate the Maximum Prime Factor in XSLT? We simply wrap up the definition above in an <xsl:function> and ... get the result!

 <xsl:function name="f:maxPrimeFactor" as="xs:integer">
  <xsl:param name="pNum" as="xs:integer"/>

  <xsl:sequence select=
   "if(f:isPrime($pNum))
      then $pNum
      else
        for $vEnd in xs:integer(floor(f:sqrt($pNum, 0.1E0))),
            $vDiv1 in (2 to $vEnd)[$pNum mod . = 0][1],
            $vDiv2 in $pNum idiv $vDiv1
          return
            max((f:maxPrimeFactor($vDiv1),f:maxPrimeFactor($vDiv2)))
   "/>
 </xsl:function>

然后，我们可以计算任何自然数的MPF ，例如:

We can, then, calculate the MPF for any natural number, for example:

f:maxPrimeFactor(600851475143) = 6857

关于效率，此转换仅需0.109秒.

简洁高效的XSLT代码的其他示例:

• Tim Bray 的 此处 .
• 级联 删除
• 传递闭包
• 查找所有字谜 一个单词
• > 语料库(旧约)的一致性
• 拼写检查 (莎士比亚的《奥赛罗》)
• 数独求解器
• 通用的编译器系统- JSON解析器 和XPath2 .0.

• Tim Bray's Wide Finder, as solved here.
• Cascade deletions
• Transitive closure
• Finding all anagrams of a word
• Concordance of a text corpus (the Old Testament)
• Spelling checking (Shakespear's Othello)
• Sudoku solver
• A general compiler-compiler system -- the LR-Parsing Framework of FXSL, used successfully for a parser of JSON and XPath2.0.

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