意想不到的:

1. PHP 8命名参数语法

Unexpected ':'， expected '，' or ')'

如果试图在PHP < 8的版本中使用PHP 8的新命名形参功能，将会出现以下错误:

$table->string(column:'Name');

解决方案:

将PHP版本升级到PHP 8.0.0或更高版本 不要使用命名参数(按照预期的顺序传递参数)

2. 裁剪类::分隔符

以“解析错误:语法错误，意外的‘:’”开头的错误消息可能是由于错误地将类静态引用class::$Variable写成class:$Variable而引起的。

意外的T_CONSTANT_ENCAPSED_STRING意外的t_encapsed_and_空白

T_CONSTANT_ENCAPSED_STRING和T_ENCAPSED_AND_WHITESPACE是指带引号的“字符串”字面量。

它们在不同的上下文中使用，但语法问题非常相似。t_encaged…警告出现在双引号的字符串上下文中，而T_CONSTANT…字符串经常在普通PHP表达式或语句中出错。

Incorrect variable interpolation And it comes up most frequently for incorrect PHP variable interpolation: ⇓ ⇓ echo "Here comes a $wrong['array'] access"; Quoting arrays keys is a must in PHP context. But in double quoted strings (or HEREDOCs) this is a mistake. The parser complains about the contained single quoted 'string', because it usually expects a literal identifier / key there. More precisely it's valid to use PHP2-style simple syntax within double quotes for array references: echo "This is only $valid[here] ..."; Nested arrays or deeper object references however require the complex curly string expression syntax: echo "Use {$array['as_usual']} with curly syntax."; If unsure, this is commonly safer to use. It's often even considered more readable. And better IDEs actually use distinct syntax colorization for that. Missing concatenation If a string follows an expression, but lacks a concatenation or other operator, then you'll see PHP complain about the string literal: ⇓ print "Hello " . WORLD " !"; While it's obvious to you and me, PHP just can't guess that the string was meant to be appended there. Confusing string quote enclosures The same syntax error occurs when confounding string delimiters. A string started by a single ' or double " quote also ends with the same. ⇓ print "<a href="' . $link . '">click here</a>"; ⌞⎽⎽⎽⎽⎽⎽⎽⎽⌟⌞⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⌟⌞⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⌟ That example started with double quotes. But double quotes were also destined for the HTML attributes. The intended concatenation operator within however became interpreted as part of a second string in single quotes. Tip: Set your editor/IDE to use slightly distinct colorization for single and double quoted strings. (It also helps with application logic to prefer e.g. double quoted strings for textual output, and single quoted strings only for constant-like values.) This is a good example where you shouldn't break out of double quotes in the first place. Instead just use proper \" escapes for the HTML attributes´ quotes: print "<a href=\"{$link}\">click here</a>"; While this can also lead to syntax confusion, all better IDEs/editors again help by colorizing the escaped quotes differently. Missing opening quote Equivalently are forgotten opening "/' quotes a recipe for parser errors: ⇓ make_url(login', 'open'); Here the ', ' would become a string literal after a bareword, when obviously login was meant to be a string parameter. Array lists If you miss a , comma in an array creation block, the parser will see two consecutive strings: array( ⇓ "key" => "value" "next" => "....", ); Note that the last line may always contain an extra comma, but overlooking one in between is unforgivable. Which is hard to discover without syntax highlighting. Function parameter lists The same thing for function calls: ⇓ myfunc(123, "text", "and" "more") Runaway strings A common variation are quite simply forgotten string terminators: ⇓ mysql_evil("SELECT * FROM stuffs); print "'ok'"; ⇑ Here PHP complains about two string literals directly following each other. But the real cause is the unclosed previous string of course. HEREDOC indentation Prior PHP 7.3, the heredoc string end delimiter can't be prefixed with spaces: print <<< HTML <link..> HTML; ⇑ Solution: upgrade PHP or find a better hoster.

另请参阅

PHP中关联数组的插值(双引号字符串) 语法错误，意外的T_CONSTANT_ENCAPSED_STRING 语法错误，PHP中意外的T_CONSTANT_ENCAPSED_STRING SQL查询中出现意外的T_CONSTANT_ENCAPSED_STRING错误

意外的'endwhile' (T_ENDWHILE)

语法使用冒号-如果没有冒号，就会发生上述错误。

<?php while($query->fetch()): ?>
 ....
<?php endwhile; ?>

这种语法的替代方法是使用花括号:

<?php while($query->fetch()) { ?>
  ....
<?php } ?>

http://php.net/manual/en/control-structures.while.php

意外的'continue' (T_CONTINUE)

Continue是一个语句(如for或if)，必须单独显示。它不能用作表达式的一部分。部分原因是continue不返回值，但在表达式中，每个子表达式都必须产生某个值，因此整个表达式都会产生一个值。这就是语句和表达式的区别。

这意味着continue不能用于三元语句或任何需要返回值的语句。

意外的“中断”(T_BREAK)

休息也是一样;当然可以。它也不能用于表达式上下文，而是一个严格语句(与foreach或if块处于同一级别)。

意外的“返回”(T_RETURN)

对于return来说，这可能更令人惊讶，但这也只是一个块级语句。它确实向更高的作用域/函数返回一个值(或NULL)，但它不作为表达式本身计算。→也就是说:return(return(false);;

意想不到的(

现在，在过时的PHP版本中经常可以看到意外的[array括号]。短数组语法从PHP >= 5.4开始可用。旧的安装只支持array()。

$php53 = array(1, 2, 3);
$php54 = [1, 2, 3];
         ⇑

数组函数结果解引用同样不适用于旧的PHP版本:

$result = get_whatever()["key"];
                      ⇑

这个错误在PHP中意味着什么?-“语法错误，意外的\[”显示了最常见和实用的解决方案。

不过，最好还是升级PHP安装。对于共享网络托管计划，首先要研究是否可以使用SetHandler php5 56-fcgi来启用新的运行时。

参见:

对函数result→进行解引用的PHP语法，从PHP 5.4开始可能 PHP语法错误，意外的“[” 数组的简写:是否存在像{}或[]这样的文字语法? PHP 5.3.10 vs PHP 5.5.3语法错误 数组()和[]的区别 PHP数组语法解析错误

顺便说一下，如果你对老版本和慢版本的PHP很感兴趣的话，还有预处理器和PHP 5.4语法下转换器。

导致意外语法错误的其他原因

如果不是PHP版本不匹配，那么通常是一个简单的拼写错误或新手语法错误:

You can't use array property declarations/expressions in classes, not even in PHP 7. protected $var["x"] = "Nope"; ⇑ Confusing [ with opening curly braces { or parentheses ( is a common oversight. foreach [$a as $b) ⇑ Or even: function foobar[$a, $b, $c] { ⇑ Or trying to dereference constants (before PHP 5.6) as arrays: $var = const[123]; ⇑ At least PHP interprets that const as a constant name. If you meant to access an array variable (which is the typical cause here), then add the leading $ sigil - so it becomes a $varname. You are trying to use the global keyword on a member of an associative array. This is not valid syntax: global $var['key'];

结束方括号

这种情况比较少见，但是终止数组[括号]也会出现语法错误。

同样，与)括号或}大括号不匹配是常见的: 函数foobar($a， $b， $c] { ⇑ 或者试图结束一个没有数组的数组: $var = 2]; 这通常发生在多行和嵌套数组声明中。 $数组=[1,2,3],4(5、6 (7 [8][9 10]],11),12]],15); ⇑ 如果是，请使用IDE进行括号匹配以查找任何过早的]数组闭包。至少使用更多的空格和换行来缩小范围。

我认为这个话题讨论得太多了/太复杂了。使用IDE是完全避免任何语法错误的方法。我甚至会说，在没有IDE的情况下工作是不专业的。为什么?因为现代ide会在输入每个字符后检查语法。当您编写代码时，整行代码都变成红色，并且有一个很大的警告通知显示语法错误的确切类型和确切位置，那么绝对没有必要搜索其他解决方案。

使用语法检查IDE意味着:

您将(有效地)再也不会遇到语法错误，因为您在输入时就能看到它们。认真对待。

具有语法检查功能的优秀ide(它们都适用于Linux、Windows和Mac):

NetBeans(免费) PHPStorm [$199 USD] Eclipse与PHP插件[免费] Sublime [$80 USD](主要是一个文本编辑器，但可扩展的插件，如PHP语法分析器)