diff --git a/sources/tech/20170422 The root of all eval.md b/sources/tech/20170422 The root of all eval.md deleted file mode 100644 index 7f3e0a9acd..0000000000 --- a/sources/tech/20170422 The root of all eval.md +++ /dev/null @@ -1,68 +0,0 @@ -translating---geekpi - -[The root of all eval][1] -============================================================ - -Ah, the `eval` function. Loved, hated. Mostly the latter. - -``` -$ perl -E'my $program = q[say "OH HAI"]; eval $program' -OH HAI -``` - -I was a bit stunned when the `eval` function was renamed to `EVAL` in Perl 6 (back in 2013, after spec discussion [here][2]). I've never felt really comfortable with the rationale for doing so. I seem to be more or less alone in this opinion, though, which is fine. - -The rationale was "the function does something really weird, so we should flag it with upper case". Like we do with `BEGIN` and the other phasers, for example. With `BEGIN` and others, the upper-casing is motivated, I agree. A phaser takes you "outside of the normal control flow". The `eval` function doesn't. - -Other things that we upper-case are things like `.WHAT`, which look like attributes but are really specially code-generated at compile-time into something completely different. So even there the upper-casing is motivated because something outside of the normal is happening. - -`eval` in the end is just another function. Yes, it's a function with potentially quite wide-ranging side effects, that's true. But a lot of fairly standard functions have wide-ranging side effects. (To name a few: `shell`, `die`, `exit`.) You don't see anyone clamoring to upper-case those. - -I guess it could be argued that `eval` is very special because it hooks into the compiler and runtime in ways that normal functions don't, and maybe can't. (This is also how TimToady explained it in [the commit message][3] of the renaming commit.) But that's an argument from implementation details, which doesn't feel satisfactory. It applies with equal force to the lower-cased functions just mentioned. - -To add insult to injury, the renamed `EVAL` is also made deliberately harder to use: - -``` -$ perl6 -e'my $program = q[say "OH HAI"]; EVAL $program' -===SORRY!=== Error while compiling -e -EVAL is a very dangerous function!!! (use the MONKEY-SEE-NO-EVAL pragma to override this error, -but only if you're VERY sure your data contains no injection attacks) -at -e:1 -------> program = q[say "OH HAI"]; EVAL $program⏏ - -$ perl6 -e'use MONKEY-SEE-NO-EVAL; my $program = q[say "OH HAI"]; EVAL $program' -OH HAI -``` - -Firstly, injection attacks are a real issue, and no laughing matter. We should educate each other and newcomers about them. - -Secondly, that error message (`"EVAL is a very dangerous function!!!"`) is completely over-the-top in a way that damages rather than helps. I believe when we explain the dangers of code injection to people, we need to do it calmly and matter-of-factly. Not with three exclamation marks. The error message makes sense to [someone who already knows about injection attacks][4]; it provides no hints or clues for people who are unaware of the risks. - -(The Perl 6 community is not unique in `eval`-hysteria. Yesterday I stumbled across a StackOverflow thread about how to turn a string with a type name into the corresponding constructor in JavaScript. Some unlucky soul suggested `eval`, and everybody else immediately piled on to point out how irresponsible that was. Solely as a knee-jerk reaction "because eval is bad".) - -Thirdly, `MOKNEY-SEE-NO-EVAL`. Please, can we just... not. 😓 Random reference to monkies and the weird attempt at levity while switching on a nuclear-chainsaw function aside, I find it odd that a function that  _enables_  `EVAL` is called something with `NO-EVAL`. That's not Least Surprise. - -Anyway, the other day I realized how I can get around both the problem of the all-caps name and the problem of the necessary pragma: - -``` -$ perl6 -e'my &eval = &EVAL; my $program = q[say "OH HAI"]; eval $program' -OH HAI -``` - -I was so happy to realize this that I thought I'd blog about it. Apparently the very dangerous function (`!!!`) is fine again if we just give it back its old name. 😜 - --------------------------------------------------------------------------------- - -via: http://strangelyconsistent.org/blog/the-root-of-all-eval - -作者：[Carl Mäsak ][a] -译者：[译者ID](https://github.com/译者ID) -校对：[校对者ID](https://github.com/校对者ID) - -本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 - -[a]:http://strangelyconsistent.org/about -[1]:http://strangelyconsistent.org/blog/the-root-of-all-eval -[2]:https://github.com/perl6/specs/issues/50 -[3]:https://github.com/perl6/specs/commit/0b7df09ecc096eed5dc30f3dbdf568bbfd9de8f6 -[4]:http://bobby-tables.com/ diff --git a/translated/tech/20170422 The root of all eval.md b/translated/tech/20170422 The root of all eval.md new file mode 100644 index 0000000000..8e11447dc0 --- /dev/null +++ b/translated/tech/20170422 The root of all eval.md @@ -0,0 +1,66 @@ +[eval 之根][1] +============================================================ + +唉，`eval` 这个函数我又爱又恨。多数是后者。 + +``` +$ perl -E'my $program = q[say "OH HAI"]; eval $program' +OH HAI +``` + +当 `eval` 函数在 Perl 6 中被重命名为 `EVAL` 时，我感到有点震惊（回到 2013 年，[在这][2]讨论规范之后）。我从未对这样做的理由感到非常舒服。虽然这是个很好的意见，但是在这个意见上我似乎或多或少是孤独的。 + +理由是“这个函数真的很奇怪，所以我们应该用大写标记”。就像我们用 `BEGIN` 和其他 phaser 一样。使用 `BEGIN` 和其他 phaser，鼓励使用大写，这点我是同意的。phaser 能将程序“脱离正常控制流”。 但是 `eval` 函数并不能。 + +其他大写的地方像是 .WHAT 这样的东西，它看起来像属性，但是会在编译时将代码变成完全不同的东西。因为有常规之外的情况发生，因此大写甚至是被鼓励的。 + +`eval` 归根到底是另一个函数。是的，这是一个潜在大量副作用的函数。但是大量标准功能都有大量的副作用。（举几个例子：`shell`、 `die`、 `exit`）你没看到有人呼吁将它们大写。 + +我猜有人会争论说 `eval` ”是非常特别的，因为它以正常函数没有的方式 hook 到编译器和运行时。（这也是 TimToady 在将函数重命名的提交中的[提交消息][3]中解释的。）这位是一个来自实现细节的争论，然而这并不令人满意。这也同样适用与刚才提到的那些小写函数。 + +为了增加冒犯性的伤害，更名后 “EVAL” 也故意这么做： + +``` +$ perl6 -e'my $program = q[say "OH HAI"]; EVAL $program' +===SORRY!=== Error while compiling -e +EVAL is a very dangerous function!!! (use the MONKEY-SEE-NO-EVAL pragma to override this error, +but only if you're VERY sure your data contains no injection attacks) +at -e:1 +------> program = q[say "OH HAI"]; EVAL $program⏏ + +$ perl6 -e'use MONKEY-SEE-NO-EVAL; my $program = q[say "OH HAI"]; EVAL $program' +OH HAI +``` + +首先，注入攻击是一个真实的问题，并不是一个笑话。我们应该互相教育对方和新手。 + +其次，这个错误消息（`"EVAL is a very dangerous function!!!"`）以最明显的方式提示这会有危害而不是帮助。我相信当我们向人们解释代码注入的危险时，我们需要冷静并且切合实际。不用三个感叹号。错误信息对[已经知道注入攻击的人][4]来说是有意义的，对于那些不了解风险的人员，它不会提供任何提示或线索。 + +（Perl 6 社区并不是唯一对 `eval` 歇斯底里的，昨天我偶然发现了一个 StackOverflow 主题，关于如何将一个有类型名称的字符串转换为 JavaScript 中的相应构造函数，一些人不幸地提出了用 `eval`，而其他人立即集结起来指出这是多么不负责任，就像膝跳反射那样 “因为 eval 是坏的”）。 + +第三，“MOKNEY-SEE-NO-EVAL”。拜托，我们能不能不要这样。。。😓 在打开一个强力函数时，只是随机引用了猴子以及轻率的尝试，我奇怪地发现_启用_ `EVAL` 函数的是一个称为 `NO-EVAL` 的东西。这不是一个惊喜。 + +不管怎样，有一天，我意识到我可以同时解决名字问题和实用性问题： + +``` +$ perl6 -e'my &eval = &EVAL; my $program = q[say "OH HAI"]; eval $program' +OH HAI +``` + +我很高兴我意识到这点并记录下来。显然这个非常危险的功能（`!!!`）如果我们把它的旧名字改回来，那也是好的。 😜 + +-------------------------------------------------------------------------------- + +via: http://strangelyconsistent.org/blog/the-root-of-all-eval + +作者：[Carl Mäsak ][a] +译者：[geekpi](https://github.com/geekpi) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]:http://strangelyconsistent.org/about +[1]:http://strangelyconsistent.org/blog/the-root-of-all-eval +[2]:https://github.com/perl6/specs/issues/50 +[3]:https://github.com/perl6/specs/commit/0b7df09ecc096eed5dc30f3dbdf568bbfd9de8f6 +[4]:http://bobby-tables.com/