意想不到的T_IF 意想不到的T_ELSEIF 意想不到的T_ELSE 意想不到的T_ENDIF

条件控件块if、elseif和else遵循一个简单的结构。当你遇到语法错误时，很可能只是无效的块嵌套→缺少{花括号}——或者多了一个。

Missing { or } due to incorrect indentation Mismatched code braces are common to less well-formatted code such as: if((!($opt["uniQartz5.8"]!=$this->check58)) or (empty($_POST['poree']))) {if ($true) {echo"halp";} elseif((!$z)or%b){excSmthng(False,5.8)}elseif (False){ If your code looks like this, start afresh! Otherwise it's unfixable to you or anyone else. There's no point in showcasing this on the internet to inquire for help. You will only be able to fix it, if you can visually follow the nested structure and relation of if/else conditionals and their { code blocks }. Use your IDE to see if they're all paired. if (true) { if (false) { … } elseif ($whatever) { if ($something2) { … } else { … } } else { … } if (false) { // a second `if` tree … } else { … } } elseif (false) { … } Any double } } will not just close a branch, but a previous condition structure. Therefore stick with one coding style; don't mix and match in nested if/else trees. Apart from consistency here, it turns out helpful to avoid lengthy conditions too. Use temporary variables or functions to avoid unreadable if-expressions. IF cannot be used in expressions A surprisingly frequent newcomer mistake is trying to use an if statement in an expression, such as a print statement: ⇓ echo "<a href='" . if ($link == "example.org") { echo … Which is invalid of course. You can use a ternary conditional, but beware of readability impacts. echo "<a href='" . ($link ? "http://yes" : "http://no") . "</a>"; Otherwise break such output constructs up: use multiple ifs and echos. Better yet, use temporary variables, and place your conditionals before: if ($link) { $href = "yes"; } else { $href = "no"; } echo "<a href='$href'>Link</a>"; Defining functions or methods for such cases often makes sense too. Control blocks don't return "results" Now this is less common, but a few coders even try to treat if as if it could return a result: $var = if ($x == $y) { "true" }; Which is structurally identical to using if within a string concatenation / expression. But control structures (if / foreach / while) don't have a "result". The literal string "true" would also just be a void statement. You'll have to use an assignment in the code block: if ($x == $y) { $var = "true"; } Alternatively, resort to a ?: ternary comparison. If in If You cannot nest an if within a condition either: ⇓ if ($x == true and (if $y != false)) { ... } Which is obviously redundant, because the and (or or) already allows chaining comparisons. Forgotten ; semicolons Once more: Each control block needs to be a statement. If the previous code piece isn't terminated by a semicolon, then that's a guaranteed syntax error: ⇓ $var = 1 + 2 + 3 if (true) { … } Btw, the last line in a {…} code block needs a semicolon too. Semicolon too early Now it's probably wrong to blame a particular coding style, as this pitfall is too easy to overlook: ⇓ if ($x == 5); { $y = 7; } else ← { $x = -1; } Which happens more often than you might imagine. When you terminate the if () expression with ; it will execute a void statement. The ; becomes a an empty {} of its own! The {…} block thus is detached from the if, and would always run. So the else no longer had a relation to an open if construct, which is why this would lead to an Unexpected T_ELSE syntax error. Which also explains a likewise subtle variation of this syntax error: if ($x) { x_is_true(); }; else { something_else(); }; Where the ; after the code block {…} terminates the whole if construct, severing the else branch syntactically. Not using code blocks It's syntactically allowed to omit curly braces {…} for code blocks in if/elseif/else branches. Which sadly is a syntax style very common to unversed coders. (Under the false assumption this was quicker to type or read). However that's highly likely to trip up the syntax. Sooner or later additional statements will find their way into the if/else branches: if (true) $x = 5; elseif (false) $x = 6; $y = 7; ← else $z = 0; But to actually use code blocks, you do have to write {…} them as such! Even seasoned programmers avoid this braceless syntax, or at least understand it as an exceptional exception to the rule. Else / Elseif in wrong order One thing to remind yourself is the conditional order, of course. if ($a) { … } else { … } elseif ($b) { … } ↑ You can have as many elseifs as you want, but else has to go last. That's just how it is. Class declarations As mentioned above, you can't have control statements in a class declaration: class xyz { if (true) { function ($var) {} } You either forgot a function definition, or closed one } too early in such cases. Unexpected T_ELSEIF / T_ELSE When mixing PHP and HTML, the closing } for an if/elseif must be in the same PHP block <?php ?> as the next elseif/else. This will generate an error as the closing } for the if needs to be part of the elseif: <?php if ($x) { ?> html <?php } ?> <?php elseif ($y) { ?> html <?php } ?> The correct form <?php } elseif: <?php if ($x) { ?> html <?php } elseif ($y) { ?> html <?php } ?> This is more or less a variation of incorrect indentation - presumably often based on wrong coding intentions. You cannot mash other statements inbetween if and elseif/else structural tokens: if (true) { } echo "in between"; ← elseif (false) { } ?> text <?php ← else { } Either can only occur in {…} code blocks, not in between control structure tokens. This wouldn't make sense anyway. It's not like that there was some "undefined" state when PHP jumps between if and else branches. You'll have to make up your mind where print statements belong to / or if they need to be repeated in both branches. Nor can you part an if/else between different control structures: foreach ($array as $i) { if ($i) { … } } else { … } There is no syntactic relation between the if and else. The foreach lexical scope ends at }, so there's no point for the if structure to continue. T_ENDIF If an unexpected T_ENDIF is complained about, you're using the alternative syntax style if: ⋯ elseif: ⋯ else: ⋯ endif;. Which you should really think twice about. A common pitfall is confusing the eerily similar : colon for a ; semicolon. (Covered in "Semicolon too early") As indentation is harder to track in template files, the more when using the alternative syntax - it's plausible your endif; does not match any if:. Using } endif; is a doubled if-terminator. While an "unexpected $end" is usually the price for a forgotten closing } curly brace. Assignment vs. comparison So, this is not a syntax error, but worth mentioning in this context: ⇓ if ($x = true) { } else { do_false(); } That's not a ==/=== comparison, but an = assignment. This is rather subtle, and will easily lead some users to helplessly edit whole condition blocks. Watch out for unintended assignments first - whenver you experience a logic fault / misbeheviour.

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

意想不到的T_IS_EQUAL 意想不到的T_IS_GREATER_OR_EQUAL 意想不到的T_IS_IDENTICAL 意想不到的T_IS_NOT_EQUAL 意想不到的T_IS_NOT_IDENTICAL 意想不到的T_IS_SMALLER_OR_EQUAL 意想不到的< 意想不到的>

比较运算符，如==，>=，===，!=，<>，!==和<=或<和>，主要应该只在表达式中使用，例如if表达式。如果解析器抱怨它们，那么通常意味着它们周围的paren不正确或不匹配()。

Parens grouping In particular for if statements with multiple comparisons you must take care to correctly count opening and closing parenthesis: ⇓ if (($foo < 7) && $bar) > 5 || $baz < 9) { ... } ↑ Here the if condition here was already terminated by the ) Once your comparisons become sufficiently complex it often helps to split it up into multiple and nested if constructs rather. isset() mashed with comparing A common newcomer is pitfal is trying to combine isset() or empty() with comparisons: ⇓ if (empty($_POST["var"] == 1)) { Or even: ⇓ if (isset($variable !== "value")) { This doesn't make sense to PHP, because isset and empty are language constructs that only accept variable names. It doesn't make sense to compare the result either, because the output is only/already a boolean. Confusing >= greater-or-equal with => array operator Both operators look somewhat similar, so they sometimes get mixed up: ⇓ if ($var => 5) { ... } You only need to remember that this comparison operator is called "greater than or equal" to get it right. See also: If statement structure in PHP Nothing to compare against You also can't combine two comparisons if they pertain the same variable name: ⇓ if ($xyz > 5 and < 100) PHP can't deduce that you meant to compare the initial variable again. Expressions are usually paired according to operator precedence, so by the time the < is seen, there'd be only a boolean result left from the original variable. See also: unexpected T_IS_SMALLER_OR_EQUAL Comparison chains You can't compare against a variable with a row of operators: ⇓ $reult = (5 < $x < 10); This has to be broken up into two comparisons, each against $x. This is actually more a case of blacklisted expressions (due to equivalent operator associativity). It's syntactically valid in a few C-style languages, but PHP wouldn't interpret it as expected comparison chain either. Unexpected > Unexpected < The greater than > or less than < operators don't have a custom T_XXX tokenizer name. And while they can be misplaced like all they others, you more often see the parser complain about them for misquoted strings and mashed HTML: ⇓ print "<a href='z">Hello</a>"; ↑ This amounts to a string "<a href='z" being compared > to a literal constant Hello and then another < comparison. Or that's at least how PHP sees it. The actual cause and syntax mistake was the premature string " termination. It's also not possible to nest PHP start tags: <?php echo <?php my_func(); ?> ↑

参见:

php T_IS_NOT_EQUAL错误 语法错误，意外的T_IS_EQUAL 返回语句的语法错误 http://forums.phpfreaks.com/topic/96891-parse-error-syntax-error-unexpected-t-is-not-identical-expecting-or/

意想不到的“。”

如果您试图在不受支持的PHP版本中使用splat操作符(…)，就会发生这种情况。

．.． 首次在PHP 5.6中可用来捕获函数的可变数量的参数:

function concatenate($transform, ...$strings) {
    $string = '';
    foreach($strings as $piece) {
        $string .= $piece;
    }
    return($transform($string));
}

echo concatenate("strtoupper", "I'd ", "like ", 4 + 2, " apples");
// This would print:
// I'D LIKE 6 APPLES

在PHP 7.4中，可以将它用于Array表达式。

$parts = ['apple', 'pear'];
$fruits = ['banana', 'orange', ...$parts, 'watermelon'];
// ['banana', 'orange', 'apple', 'pear', 'watermelon'];

意想不到的T_LNUMBER

令牌T_LNUMBER指向一个“长”/ number。

Invalid variable names In PHP, and most other programming languages, variables cannot start with a number. The first character must be alphabetic or an underscore. $1 // Bad $_1 // Good Quite often comes up for using preg_replace-placeholders "$1" in PHP context: # ↓ ⇓ ↓ preg_replace("/#(\w+)/e", strtopupper($1) ) Where the callback should have been quoted. (Now the /e regex flag has been deprecated. But it's sometimes still misused in preg_replace_callback functions.) The same identifier constraint applies to object properties, btw. ↓ $json->0->value While the tokenizer/parser does not allow a literal $1 as variable name, one could use ${1} or ${"1"}. Which is a syntactic workaround for non-standard identifiers. (It's best to think of it as a local scope lookup. But generally: prefer plain arrays for such cases!) Amusingly, but very much not recommended, PHPs parser allows Unicode-identifiers; such that $➊ would be valid. (Unlike a literal 1). Stray array entry An unexpected long can also occur for array declarations - when missing , commas: # ↓ ↓ $xy = array(1 2 3); Or likewise function calls and declarations, and other constructs: func(1, 2 3); function xy($z 2); for ($i=2 3<$z) So usually there's one of ; or , missing for separating lists or expressions. Misquoted HTML And again, misquoted strings are a frequent source of stray numbers: # ↓ ↓ echo "<td colspan="3">something bad</td>"; Such cases should be treated more or less like Unexpected T_STRING errors. Other identifiers Neither functions, classes, nor namespaces can be named beginning with a number either: ↓ function 123shop() { Pretty much the same as for variable names.

意想不到的T_STRING

T_STRING有点用词不当。它不引用引用的“字符串”。这意味着遇到了原始标识符。这可以是空白的单词、剩余的CONSTANT或函数名、被遗忘的不带引号的字符串或任何纯文本。

Misquoted strings This syntax error is most common for misquoted string values however. Any unescaped and stray " or ' quote will form an invalid expression: ⇓ ⇓ echo "<a href="http://example.com">click here</a>"; Syntax highlighting will make such mistakes super obvious. It's important to remember to use backslashes for escaping \" double quotes, or \' single quotes - depending on which was used as string enclosure. For convenience you should prefer outer single quotes when outputting plain HTML with double quotes within. Use double quoted strings if you want to interpolate variables, but then watch out for escaping literal " double quotes. For lengthier output, prefer multiple echo/print lines instead of escaping in and out. Better yet consider a HEREDOC section. Another example is using PHP entry inside HTML code generated with PHP: $text = '<div>some text with <?php echo 'some php entry' ?></div>' This happens if $text is large with many lines and developer does not see the whole PHP variable value and focus on the piece of code forgetting about its source. Example is here See also What is the difference between single-quoted and double-quoted strings in PHP?. Unclosed strings If you miss a closing " then a syntax error typically materializes later. An unterminated string will often consume a bit of code until the next intended string value: ⇓ echo "Some text", $a_variable, "and some runaway string ; success("finished"); ⇯ It's not just literal T_STRINGs which the parser may protest then. Another frequent variation is an Unexpected '>' for unquoted literal HTML. Non-programming string quotes If you copy and paste code from a blog or website, you sometimes end up with invalid code. Typographic quotes aren't what PHP expects: $text = ’Something something..’ + ”these ain't quotes”; Typographic/smart quotes are Unicode symbols. PHP treats them as part of adjoining alphanumeric text. For example ”these is interpreted as a constant identifier. But any following text literal is then seen as a bareword/T_STRING by the parser. The missing semicolon; again If you have an unterminated expression in previous lines, then any following statement or language construct gets seen as raw identifier: ⇓ func1() function2(); PHP just can't know if you meant to run two functions after another, or if you meant to multiply their results, add them, compare them, or only run one || or the other. Short open tags and <?xml headers in PHP scripts This is rather uncommon. But if short_open_tags are enabled, then you can't begin your PHP scripts with an XML declaration: ⇓ <?xml version="1.0"?> PHP will see the <? and reclaim it for itself. It won't understand what the stray xml was meant for. It'll get interpreted as constant. But the version will be seen as another literal/constant. And since the parser can't make sense of two subsequent literals/values without an expression operator in between, that'll be a parser failure. Invisible Unicode characters A most hideous cause for syntax errors are Unicode symbols, such as the non-breaking space. PHP allows Unicode characters as identifier names. If you get a T_STRING parser complaint for wholly unsuspicious code like: <?php print 123; You need to break out another text editor. Or an hexeditor even. What looks like plain spaces and newlines here, may contain invisible constants. Java-based IDEs are sometimes oblivious to an UTF-8 BOM mangled within, zero-width spaces, paragraph separators, etc. Try to reedit everything, remove whitespace and add normal spaces back in. You can narrow it down with with adding redundant ; statement separators at each line start: <?php ;print 123; The extra ; semicolon here will convert the preceding invisible character into an undefined constant reference (expression as statement). Which in return makes PHP produce a helpful notice. The `$` sign missing in front of variable names Variables in PHP are represented by a dollar sign followed by the name of the variable. The dollar sign ($) is a sigil that marks the identifier as a name of a variable. Without this sigil, the identifier could be a language keyword or a constant. This is a common error when the PHP code was "translated" from code written in another language (C, Java, JavaScript, etc.). In such cases, a declaration of the variable type (when the original code was written in a language that uses typed variables) could also sneak out and produce this error. Escaped Quotation marks If you use \ in a string, it has a special meaning. This is called an "Escape Character" and normally tells the parser to take the next character literally. Example: echo 'Jim said \'Hello\''; will print Jim said 'hello' If you escape the closing quote of a string, the closing quote will be taken literally and not as intended, i.e. as a printable quote as part of the string and not close the string. This will show as a parse error commonly after you open the next string or at the end of the script. Very common error when specifiying paths in Windows: "C:\xampp\htdocs\" is wrong. You need "C:\\xampp\\htdocs\\". Typed properties You need PHP ≥7.4 to use property typing such as: public stdClass $obj;