Python是工程，不是艺术

 When Python first emerged on the software scene in the early 1990s,
 it spawned what is now something of a classic conflict between its proponents and
 those of another popular scripting language, Perl. Personally, I think
 the debate is tired and unwarranted today—developers are smart enough to draw their own conclusions.
 Still, this is one of the most common topics I’m asked about on the training road,
 so it seems fitting to say a few words on the topic here.

当Python九十年代初出现时，曾激起Python的支持者与另一门时髦语言Perl拥护者的之间的经典冲突。

如今这场争论已成为过去。个人认为：这场争论很令人厌烦，也毫无根据。

开发者都很聪明，知道如何选择。目前为止，这仍然是一场最著名的争论。

在我培训过程中，经常会被问及，因此有必要就这个话题说几句。

 The short story is this: you can do everything in Python that you can in Perl,
 but you can read your code after you do it. That’s it—their domains largely overlap,
 but Python is more focused on producing readable code.
 For many, the enhanced readability of Python translates to code reuseability and maintainability,
 making Python a better choice for programs that will not be written once and thrown away.
 Perl code is easy to write, but difficult to read.
 Given that most software has a lifespan much longer than its initial creation, many see Python as a more effective tool.

简而言之：Perl能做到的，Python都能做到，但你必须在写之后要能读懂它。显然，这是他们之间主要的交集。

显而易见：Python更关注代码的可读性，在大多数情况下，提高代码的可读性转化为代码的可重用性及可维护性。

这样一来，使得Python成为了一个很好的选择: 不会写后就丢弃。 Perl代码很容易写，但很难读懂。

鉴于软件都有很长的生命周期，远比初始开发要长，因此很多人视Python为更有效的工具。

 The somewhat longer story reflects the backgrounds of the designers of the two languages,
 and underscores some of the main reasons people choose to use Python.
 Python’s creator is a mathematician by training; as such, he produced a language with
 a high degree of uniformity—its syntax and toolset are remarkably coherent. Moreover,
 like math, its design is orthogonal—most of the language follows from a small set
 of core concepts. For instance, once one grasps Python’s flavor of polymorphism, the
 rest is largely just details.

这很大程度反映了两门语言设计者的背景，并体现了很多人选择使用Python的原因。

Python的缔造者是个训练有素的数学家，这就使得其发明的语言具有高度的统一性：

它的语法和工具集都带有显著的连贯性。更有甚者，像数学一样其设计具有正交性：

即语言的大部分都遵循一小组的核心概念。例如，一旦你掌握了多态，其他大部分都是细节，仅此而已。

 By contrast, the creator of the Perl language is a linguist, and its design reflects this heritage.
 There are many ways to accomplish the same tasks in Perl, and language
 constructs interact in context-sensitive and sometimes quite subtle ways—much like
 natural language. As the well-known Perl motto states, “There’s more than one way to
 do it.” Given this design, both the Perl language and its user community have historically
 encouraged freedom of expression when writing code. One person’s Perl code can
 be radically different from another’s. In fact, writing unique, tricky code is often a
 source of pride among Perl users.

相比而言，Perl的创立者是个语言学家，因此其设计反映了这种语言的特性。

在Perl中，做同样的任务，可以有很多种方法，语言的结构受语境交互影响。

这种影响有时是非常敏感的，非常像自然语言。恰如一句著名的Perl座右铭所说：

条条道路通罗马! 鉴于这种设计，不仅Perl语言本身以及Perl用户社区：

都鼓励并提倡在写代码时，追求自由的精神。因此一个人写出来的代码很可能与他人截然不同! 

事实上，Perl开发者常以编写独特的，很花俏的代码为荣！

 But as anyone who has done any substantial code maintenance should be able to attest,
 freedom of expression is great for art, but lousy for engineering. In engineering, we
 need a minimal feature set and predictability. In engineering, freedom of expression
 can lead to maintenance nightmares. As more than one Perl user has confided to me,
 the result of too much freedom is often code that is much easier to rewrite from scratch
 than to modify.

但是那些曾经维护过大量代码的人可以证明:自由表达的精神对艺术而言非常棒。

但对工程而言，就非常令人讨厌了。从工程的角度，我们需要最小化功能集及可预测性。

在工程领域，自由表达会导致维护的噩梦。不止一个Perl用户向我吐露:

太过于自由的结果就是：程序很容易重头写起，但修改起来就很难了！

 Consider this: when people create a painting or a sculpture, they do so for themselves
 for purely aesthetic purposes. The possibility of someone else having to change that
 painting or sculpture later does not enter into it. This is a critical difference between
 art and engineering. When people write software, they are not writing it for themselves.
 In fact, they are not even writing primarily for the computer. Rather, good
 programmers know that code is written for the next human being who has to read it in
 order to maintain or reuse it. If that person cannot understand the code, it’s all but useless
 in a realistic development scenario.

鉴于此：当人们对雕像涂抹漆画，出于纯粹美学的角度，他们可以随意涂抹.

至于今后别人不得不改变他的漆画或者雕像，都不在其考虑的范畴。这就是艺术和工程最关键的区别。

当人们写代码时，他们并不能纯粹为自己而写。事实上，他们甚至不是专门为计算机而写的。

当然啦，优秀的程序员知道：代码是为今后维护甚至重写的人而写。

如果负责维护的人完全不能理解代码,那么在现实中，这些代码几乎毫无用处。

 This is where many people find that Python most clearly differentiates itself from scripting
 languages like Perl. Because Python’s syntax model almost forces users to write
 readable code, Python programs lend themselves more directly to the full software
 development cycle. And because Python emphasizes ideas such as limited interactions,
 uniformity, regularity, and consistency, it more directly fosters code that can be used
 long after it is first written.

这就是很多人发现Python区别于另一门脚本语言Perl最显著的地方。

因为Python的语法模式强迫用户去写可读的代码，Python语言会引导他们朝完整的软件开发流程前进。

因为Python更强调:有限交互性、一致性、规则性以及统一连贯性，会更进一步导致：

Python自首次编写后，可以运行很长一段时间。

 In the long run, Python’s focus on code quality in itself boosts programmer productivity,
 as well as programmer satisfaction. Python programmers can be creative, too, and
 as we’ll see, the language does offer multiple solutions for some tasks. At its core,
 though, Python encourages good engineering in ways that other scripting languages
 often do not.

长期以来，Python专注于代码的质量也提升了程序员的生产力，和开发者的满意度。

Python的程序员会变得更富有创造性，并且我们以后会明白，对某些项目而言：

这门语言的确提供了多种解决方案。就核心而言，Python提倡优秀工程的开发方式是其他脚本语言所不具备的。

 At least, that’s the common consensus among many people who have adopted Python.
 You should always judge such claims for yourself, of course, by learning what Python
 has to offer.

至少，这是很多采用Python者之间的共识。当然你自己也能判断:Python到底为你提供了什么。

NOTE:英文文章摘自《Learning Python》Python is engineer，not art部分.