PHP parse/syntax errors; and how to solve them?
Everyone runs into syntax errors. Even experienced programmers make typos. For newcomers it's just part of the learning process. However, it's often easy to interpret error messages such as:
PHP Parse error: syntax error, unexpected '{' in index.php on line 20
The unexpected symbol isn't always the real culprit. But the line number gives a rough idea where to start looking.
Always look at the code context . The syntax mistake often hides in the mentioned or in previous code lines . Compare your code against syntax examples from the manual.
While not every case matches the other. Yet there are some general steps to solve syntax mistakes . This references summarized the common pitfalls:
Unexpected T_STRING
Unexpected T_VARIABLE
Unexpected '$varname' (T_VARIABLE)
Unexpected T_CONSTANT_ENCAPSED_STRING
Unexpected T_ENCAPSED_AND_WHITESPACE
Unexpected $end
Unexpected T_FUNCTION…
Unexpected {
Unexpected }
Unexpected (
Unexpected )
Unexpected [
Unexpected ]
Unexpected T_IF
Unexpected T_FOREACH
Unexpected T_FOR
Unexpected T_WHILE
Unexpected T_DO
Unexpected T_PRINT
Unexpected T_ECHO
Unexpected T_LNUMBER
Unexpected T_INLINE_HTML…
Unexpected T_PAAMAYIM_NEKUDOTAYIM…
Unexpected T_OBJECT_OPERATOR…
Unexpected T_DOUBLE_ARROW…
Unexpected T_SL…
Unexpected T_BOOLEAN_OR…
Unexpected T_BOOLEAN_AND…
Unexpected T_IS_EQUAL
Unexpected T_IS_GREATER_OR_EQUAL
Unexpected T_IS_IDENTICAL
Unexpected T_IS_NOT_EQUAL
Unexpected T_IS_NOT_IDENTICAL
Unexpected T_IS_SMALLER_OR_EQUAL
Unexpected <
Unexpected >
Unexpected T_NS_SEPARATOR…
Unexpected character in input: ' ' (ASCII=92) state=1
Unexpected 'public' (T_PUBLIC)
Unexpected 'private' (T_PRIVATE)
Unexpected 'protected' (T_PROTECTED)
Unexpected 'final' (T_FINAL)…
Unexpected T_STATIC…
Unexpected T_CLASS…
Unexpected T_DNUMBER
Unexpected , (comma)
Unpexected . (period)
Unexpected ; (semicolon)
Unexpected * (asterisk)
Unexpected : (colon)
Closely related references:
“” smart '' quotes mean nothing to PHP And:
While Stack Overflow is also welcoming rookie coders, it's mostly targetted at professional programming questions.
If your browser displays error messages such as "SyntaxError: illegal character", then it's not actually php-related, but a javascript-syntax error.
What are syntax errors?
PHP belongs to the C-style and imperative programming languages. It has rigid grammar rules, which it cannot recover from when encountering misplaced symbols or identifiers. It can't guess your coding intentions.
Most important tips
There are a few basic precautions you can always take:
Use proper code indentation , or adopt any lofty coding style. Readability prevents irregularities.
Use an IDE or editor for PHP with syntax highlighting . Which also help with parentheses/bracket balancing.
Read the language reference and examples in the manual. Twice, to become somewhat proficient.
How to interpret parser errors
A typical syntax error message reads:
Parse error: syntax error, unexpected T_STRING , expecting ' ; ' in file.php on line 217
Which lists the possible location of a syntax mistake. See the mentioned file name and line number .
A moniker such as T_STRING explains which symbol the parser/tokenizer couldn't process finally. This isn't necessarily the cause of the syntax mistake however.
It's important to look into previous code lines as well. Often syntax errors are just mishaps that happened earlier. The error line number is just where the parser conclusively gave up to process it all.
Solving syntax errors
There are many approaches to narrow down and fix syntax hiccups.
Open the mentioned source file. Look at the mentioned code line .
For runaway strings and misplaced operators this is usually where you find the culprit.
Read the line left to right and imagine what each symbol does.
More regularly you need to look at preceding lines as well.
In particular, missing ; semicolons are missing at the previous line end / statement. (At least from the stylistic viewpoint. )
If { code blocks } are incorrectly closed or nested, you may need to investigate even further up the source code. Use proper code indentation to simplify that.
Look at the syntax colorization !
Strings and variables and constants should all have different colors.
Operators +-*/. should be be tinted distinct as well. Else they might be in the wrong context.
If you see string colorization extend too far or too short, then you have found an unescaped or missing closing " or ' string marker.
Having two same-colored punctuation characters next to each other can also mean trouble. Usually operators are lone if it's not ++ , -- , or parentheses following an operator. Two strings/identifiers directly following each other are incorrect in most contexts.
Whitespace is your friend . Follow any coding style.
Break up long lines temporarily.
You can freely add newlines between operators or constants and strings. The parser will then concretise the line number for parsing errors. Instead of looking at very lengthy code, you can isolate the missing or misplaced syntax symbol.
Split up complex if statements into distinct or nested if conditions.
Instead of lengthy math formulas or logic chains, use temporary variables to simplify the code. (More readable = fewer errors.)
Add newlines between:
Partitioning up long code blocks really helps locating the origin of syntax errors.
Comment out offending code.
If you can't isolate the problem source, start to comment out (and thus temporarily remove) blocks of code.
As soon as you got rid of the parsing error, you have found the problem source. Look more closely there.
Sometimes you want to temporarily remove complete function/method blocks. (In case of unmatched curly braces and wrongly indented code.)
When you can't resolve the syntax issue, try to rewrite the commented out sections from scratch .
As a newcomer, avoid some of the confusing syntax constructs.
The ternary ? : ? : condition operator can compact code and is useful indeed. But it doesn't aid readability in all cases. Prefer plain if statements while unversed.
PHP's alternative syntax ( if: / elseif: / endif; ) is common for templates, but arguably less easy to follow than normal { code } blocks.
The most prevalent newcomer mistakes are:
Missing semicolons ; for terminating statements / lines.
Mismatched string quotes for " or ' and unescaped quotes within.
Forgotten operators, in particular for string . concatenation.
Unbalanced ( parentheses ) . Count them in the reported line. Are there an equal number of them?
Don't forget that solving one syntax problem can uncover the next.
If you make one issue go away, but another crops up in some code below, you're mostly on the right path.
If after editing a new syntax error crops up in the same line, then your attempted change was possibly a failure. (Not always though.)
Restore a backup of previously working code, if you can't fix it.
diff of the broken and last working version. Which might be enlightening as to what the syntax problem is. Invisible stray Unicode characters : In some cases you need to use a hexeditor or different editor/viewer on your source. Some problems cannot be found just from looking at your code.
Try grep --color -P -n "[x80-xFF]" file.php as the first measure to find non-ASCII symbols.
In particular BOMs, zero-width spaces, or non-breaking spaces, and smart quotes regularly can find their way into source code.
Take care of which type of linebreaks are saved in files.
PHP just honors n newlines, not r carriage returns.
Which is occasionally an issue for MacOS users (even on OS X for misconfigured editors).
It often only surfaces as an issue when single-line // or # comments are used. Multiline /*...*/ comments do seldomly disturb the parser when linebreaks get ignored.
If your syntax error does not transmit over the web : It happens that you have a syntax error on your machine. But posting the very same file online does not exhibit it any more. Which can only mean one of two things:
You are looking at the wrong file!
Or your code contained invisible stray Unicode (see above). You can easily find out: Just copy your code back from the web form into your text editor.
Check your PHP version . Not all syntax constructs are available on every server.
Don't use PHP's reserved keywords as identifiers for functions / methods, classes or constants.
Trial-and-error is your last resort.
If all else fails, you can always google your error message. Syntax symbols aren't as easy to search for (Stack Overflow itself is indexed by SymbolHound though). Therefore it may take looking through a few more pages before you find something relevant.
Further guides:
White screen of death
If your website is just blank, then typically a syntax error is the cause. Enable their display with:
error_reporting = E_ALL display_errors = 1 In your php.ini generally, or via .htaccess for mod_php, or even .user.ini with FastCGI setups.
Enabling it within the broken script is too late, because PHP can't even interpret/run the first line. A quick workaround is crafting a wrapper script, say test.php :
<?php
error_reporting(E_ALL);
ini_set("display_errors", 1);
include("./broken-script.php");
Then invoke the failing code by accessing this wrapper script.
It also helps to enable PHP's error_log and look into your webserver's error.log when a script crashes with HTTP 500 responses.
I think this topic is totally overdiscussed/overcomplicated. Using an IDE is THE way to go to completely avoid any syntax errors. I would even say that working without an IDE is kind of unprofessional. Why? Because modern IDEs check your syntax after every character you type. When you code and your entire line turns red, and a big warning notice shows you the exact type and the exact position of the syntax error, then there's absolutely no need to search for another solution.
Using a syntax-checking IDE means:
You'll (effectively) never run into syntax errors again, simply because you see them right as you type. Seriously.
Excellent IDEs with syntax check (all of them are available for Linux, Windows and Mac):
Unexpected [
These days, the unexpected [ array bracket is commonly seen on outdated PHP versions. The short array syntax is available since PHP >= 5.4 . Older installations only support array() .
$php53 = array(1, 2, 3);
$php54 = [1, 2, 3];
⇑
Array function result dereferencing is likewise not available for older PHP versions:
$result = get_whatever()["key"];
⇑
Reference - What does this error mean in PHP? - "Syntax error, unexpected [ " shows the most common and practical workarounds.
Though, you're always better off just upgrading your PHP installation. For shared webhosting plans, first research if eg SetHandler php56-fcgi can be used to enable a newer runtime.
See also:
BTW, there are also preprocessors and PHP 5.4 syntax down-converters if you're really clingy with older + slower PHP versions.
Other causes for Unexpected [ syntax errors
If it's not the PHP version mismatch, then it's oftentimes a plain typo or newcomer syntax mistake:
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 $varname .
Unexpected ] closing square bracket
This is somewhat rarer, but there are also syntax accidents with the terminating array ] bracket.
Again mismatches with ) parentheses or } curly braces are common:
function foobar($a, $b, $c] {
⇑
Or trying to end an array where there isn't one:
$var = 2];
Which often occurs in multi-line and nested array declarations.
$array = [1,[2,3],4,[5,6[7,[8],[9,10]],11],12]],15];
⇑
If so, use your IDE for bracket matching to find any premature ] array closure. At the very least use more spacing and newlines to narrow it down.
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