blocks|key|1958519|text|我不知道为什么，但这就是Perl对它的理解：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1958520|perl+-MO=Deparse+-w+yuck
BEGIN+{+$%5EW+=+1;+}
use+warnings;
use+strict+'refs';
'error'->Syntax(!exit(0));
yuck+syntax+OK|code-block|syntax|javascript|1958521|解析器似乎认为您正在调用error-object上的Syntax方法...确实很奇怪！|offset|length|style|CODE|1958522|entityMap^0|0|0|C|5|Q|6|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]|$I|T|J|U|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|V|8|@]|9|@]|A|$]]]|N|$]]

I don't know why, but this is what Perl makes of it:

<pre><code>perl -MO=Deparse -w yuck
BEGIN { $^W = 1; }
use warnings;
use strict 'refs';
'error'-&gt;Syntax(!exit(0));
yuck syntax OK
</code></pre>

It seems that the parser thinks you're calling the method <code>Syntax</code> on the <code>error</code>-object... Strange indeed!

blocks|key|2033401|text|Perl有一种称为“间接方法表示法”的语法。它允许|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2033402|Foo->new($bar)|code-block|syntax|javascript|2033403|要写成|2033404|new+Foo+$bar|2033405|所以这意味着|2033406|Syntax+error+!+exit+0;|2033407|等同于|2033408|error->Syntax(!+exit+0);|2033409|或|2033410|error->Syntax(!exit(0));|2033411|它不仅是有效的语法，而且不会导致运行时错误，因为首先执行的是exit(0)。|offset|length|style|CODE|2033412|entityMap^0|0|0|0|0|0|0|0|0|0|0|U|7|0^^$0|@$1|2|3|4|5|6|7|14|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|15|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|16|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|17|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|18|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|19|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|1A|8|@]|9|@]|A|$]]|$1|Q|3|R|5|D|7|1B|8|@]|9|@]|A|$E|F]]|$1|S|3|T|5|6|7|1C|8|@]|9|@]|A|$]]|$1|U|3|V|5|D|7|1D|8|@]|9|@]|A|$E|F]]|$1|W|3|X|5|6|7|1E|8|@$Y|1F|Z|1G|10|11]]|9|@]|A|$]]|$1|12|3|-4|5|6|7|1H|8|@]|9|@]|A|$]]]|13|$]]

Perl has a syntax called "indirect method notation". It allows

<pre><code>Foo-&gt;new($bar)
</code></pre>

to be written as

<pre><code>new Foo $bar
</code></pre>

So that means

<pre><code>Syntax error ! exit 0;
</code></pre>

is the same as

<pre><code>error-&gt;Syntax(! exit 0);
</code></pre>

or

<pre><code>error-&gt;Syntax(!exit(0));
</code></pre>

Not only is it valid syntax, it doesn't result in a run-time error because the first thing executed is <code>exit(0)</code>.

blocks|key|3684133|text|您没有得到错误的原因是第一次执行的代码是|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3684134|exit(0);|code-block|syntax|javascript|3684135|因为第一行没有分号：|3684136|Syntax+error!|3684137|编译器将猜测(错误地)这是一个带有not操作符!的子例程调用。然后，它将执行该子例程的参数，该子例程恰好为exit(0)，此时程序退出并将errorlevel设置为0。不会执行任何其他操作，因此不会再报告运行时错误。|offset|length|style|CODE|3684138|您会注意到，如果您将exit(0)更改为类似于print+"Hello+world!"的值，您会得到一个错误：|3684139|Can't+locate+object+method+"Syntax"+via+package+"error"+...|3684140|您的错误级别将被设置为：|3684141|>+echo+%25errorlevel%25
255|3684142|entityMap^0|0|0|0|0|H|3|N|1|1H|7|0|A|7|N|K|0|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|11|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|12|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|13|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|14|8|@$M|15|N|16|O|P]|$M|17|N|18|O|P]|$M|19|N|1A|O|P]]|9|@]|A|$]]|$1|Q|3|R|5|6|7|1B|8|@$M|1C|N|1D|O|P]|$M|1E|N|1F|O|P]]|9|@]|A|$]]|$1|S|3|T|5|D|7|1G|8|@]|9|@]|A|$E|F]]|$1|U|3|V|5|6|7|1H|8|@]|9|@]|A|$]]|$1|W|3|X|5|D|7|1I|8|@]|9|@]|A|$E|F]]|$1|Y|3|-4|5|6|7|1J|8|@]|9|@]|A|$]]]|Z|$]]

The reason you do not get an error is that the first executed code is 

<pre><code>exit(0);
</code></pre>

Because you did not have a semicolon on the first line:

<pre><code>Syntax error!
</code></pre>

The compiler will guess (incorrectly) that this is a subroutine call with a <code>not</code> operator <code>!</code> thrown in. It will then execute the arguments to this subroutine, which happens to be <code>exit(0)</code>, at which point the program exits and sets errorlevel to 0. Nothing else is executed, so no more runtime errors are reported.

You will notice that if you change <code>exit(0)</code> to something like <code>print "Hello world!"</code> you do get an error:

<pre class="lang-none prettyprint-override"><code>Can't locate object method "Syntax" via package "error" ...
</code></pre>

and your error level will be set:

<pre><code>&gt; echo %errorlevel%
255
</code></pre>

blocks|key|3595464|text|如上所述，这是由间接方法调用表示法引起的。你可以对此进行警告：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3595465|use+strict;
use+warnings;
no+indirect;

Syntax+error!

exit+0;|code-block|syntax|javascript|3595466|产生：|3595467|Indirect+call+of+method+"Syntax"+on+object+"error"+at+-+line+5.|3595468|这需要indirect+CPAN+module。|offset|length|3595469|您还可以使用no+indirect+"fatal";导致程序终止(这就是我所做的)|style|CODE|3595470|entityMap|0|LINK|mutability|MUTABLE|url|http://metacpan.org/module/indirect^0|0|0|0|0|3|K|0|0|6|K|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|11|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|12|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|13|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|14|8|@]|9|@$M|15|N|16|1|17]]|A|$]]|$1|O|3|P|5|6|7|18|8|@$M|19|N|1A|Q|R]]|9|@]|A|$]]|$1|S|3|-4|5|6|7|1B|8|@]|9|@]|A|$]]]|T|$U|$5|V|W|X|A|$Y|Z]]]]

As noted above this is caused by the indirect method calling notation. You can warn on this:

<pre><code>use strict;
use warnings;
no indirect;

Syntax error!

exit 0;
</code></pre>

Produces:

<pre><code>Indirect call of method "Syntax" on object "error" at - line 5.
</code></pre>

This requires the <a href="http://metacpan.org/module/indirect">indirect CPAN module</a>.

You can also use <code>no indirect "fatal";</code> to cause the program to die (this is what I do)

blocks|key|2033456|text|试试Perl+6，它似乎更容易满足你的期望：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|2033457|===SORRY!===+Error+while+compiling+synerror.p6
Negation+metaoperator+not+followed+by+valid+infix
at+synerror.p6:1
------>+Syntax+error!⏏<EOL>
++++expecting+any+of:
++++++++infix
++++++++infix+stopper|code-block|syntax|javascript|2033458|entityMap|0|LINK|mutability|MUTABLE|url|https://perl6.org/^0|2|6|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

Try <a href="https://perl6.org/">Perl 6</a>, it seems to fulfill your expectations more readily:

<pre><code>===SORRY!=== Error while compiling synerror.p6
Negation metaoperator not followed by valid infix
at synerror.p6:1
------&gt; Syntax error!⏏&lt;EOL&gt;
 expecting any of:
 infix
 infix stopper
</code></pre>

blocks|key|1958693|text|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1958694|在这个paper中，我们的目标是回答编程语言社区中一个长期悬而未决的问题:是否有可能在不创建有效的Perl的情况下在墙上涂抹油漆？|blockquote|offset|length|1958695|1958696|1958697|TLDR；|1958698|entityMap|0|LINK|mutability|MUTABLE|url|https://famicol.in/sigbovik/^0|0|3|5|0|0|0|0|0^^$0|@$1|2|3|-4|4|5|6|R|7|@]|8|@]|9|$]]|$1|A|3|B|4|C|6|S|7|@]|8|@$D|T|E|U|1|V]]|9|$]]|$1|F|3|-4|4|5|6|W|7|@]|8|@]|9|$]]|$1|G|3|-4|4|5|6|X|7|@]|8|@]|9|$]]|$1|H|3|I|4|5|6|Y|7|@]|8|@]|9|$]]|$1|J|3|-4|4|5|6|Z|7|@]|8|@]|9|$]]]|K|$L|$4|M|N|O|9|$P|Q]]]]

<blockquote>
 In this <a href="https://famicol.in/sigbovik/" rel="nofollow noreferrer">paper</a>, we aim to answer a long-standing open problem in the
 programming languages community: is it possible to smear paint on the
 wall without creating valid Perl?
</blockquote>

TLDR; Hardly

I'm running ActiveState's 32 bit <a href="https://www.activestate.com/activeperl" rel="noreferrer">ActivePerl</a> 5.14.2 on Windows 7. I wanted to mess around with a Git pre-commit hook to detect programs being checked in with syntax errors. (Somehow I just managed to do such a bad commit.) So as a test program I randomly jotted this:

<pre><code>use strict;
use warnings;

Syntax error!

exit 0;
</code></pre>

However, it compiles and executes with no warnings, and errorlevel is zero on exit. How is this valid syntax?

Why is this program valid? I was trying to create a syntax error

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我在Windows7上运行的是ActiveState的32位 5.14.2，我想用一个Git预提交钩子来检测存在语法错误的程序。(不知何故，我只是设法完成了如此糟糕的提交。)因此，作为一个测试程序，我随机写了以下内容：use strict;use warnings;Syntax error!exit 0;但是，它在编译...

问为什么这个程序是有效的？我试图创建一个语法错误
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问为什么这个程序是有效的？我试图创建一个语法错误EN