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1. Function declaration parameters

   A rarer occurrence for this error is trying to use expressions as default function parameters. This is not supported, even in PHP7:

   function header_fallback($value, $expires = time() + 90000) {
   

   Parameters in a function declaration can only be literal values or constant expressions. Unlike for function invocations, where you can freely use whatever(1+something()*2) etc.

2. Class property defaults

   Same thing for class member declarations, where only literal/constant values are allowed, not expressions:

   class xyz {                   ⇓
       var $default = get_config("xyz_default");
   

   Put such things in the constructor. See also Why don't PHP attributes allow functions?

   Again note that PHP 7 only allows var $xy = 1 + 2 +3; constant expressions there.

3. JavaScript syntax in PHP

   Using JavaScript or jQuery syntax won't work in PHP for obvious reasons:

   <?php      ⇓
       print $(document).text();
   

   When this happens, it usually indicates an unterminated preceding string; and literal <script> sections leaking into PHP code context.

4. isset(()), empty, key, next, current

   Both isset() and empty() are language built-ins, not functions. They need to access a variable directly. If you inadvertently add a pair of parentheses too much, then you'd create an expression however:

             ⇓
   if (isset(($_GET["id"]))) {
   

   The same applies to any language construct that requires implicit variable name access. These built-ins are part of the language grammar, therefore don't permit decorative extra parentheses.

   User-level functions that require a variable reference -but get an expression result passed- lead to runtime errors instead.

Curly braces { and } enclose code blocks. And syntax errors about them usually indicate some incorrec nesting.

1. Unmatched subexpressions in an if

   Most commonly unbalanced ( and ) are the cause if the parser complains about the opening curly { appearing too early. A simple example:

                                 ⇓
   if (($x == $y) && (2 == true) {
   

   Count your parens or use an IDE which helps with that. Also don't write code without any spaces. Readability counts.

2. { and } in expression context

   You can't use curly braces in expressions. If you confuse parentheses and curlys, it won't comply to the language grammer:

              ⇓
   $var = 5 * {7 + $x};
   

   There are a few exceptions for identifier construction, such as local scope variable ${references}.

3. Variable variables or curly var expressions

   This is pretty rare. But you might also get { and } parser complaints for complex variable expressions:

                         ⇓
   print "Hello {$world[2{]} !";
   

   Though there's a higher likelihood for an unexpected } in such contexts.

1. Last statement in a code block

   It can happen for any unterminated expression.

   And if the last line in a function/code block lacks a trailing ; semicolon:

   function whatever() {
       doStuff()
   }            ⇧
   

   Here the parser can't tell if you perhaps still wanted to add + 25; to the function result or something else.

2. Invalid block nesting / Forgotten {

   You'll sometimes see this parser error when a code block was } closed too early, or you forgot an opening { even:

   function doStuff() {
       if (true)    ⇦
           print "yes";
       }
   }   ⇧
   

   In above snippet the if didn't have an opening { curly brace. Thus the closing } one below became redundant. And therefore the next closing }, which was intended for the function, was not associatable to the original opening { curly brace.

   Such errors are even harder to find without proper code indentation. Use an IDE and bracket matching.

1. Function declaration parameters

   A rarer occurrence for this error is trying to use expressions as default function parameters. This is not supported, even in PHP7:

   function header_fallback($value, $expires = time() + 90000) {
   

   Parameters in a function declaration can only be literal values or constant expressions. Unlike for function invocations, where you can freely use whatever(1+something()*2), etc.

2. Class property defaults

   Same thing for class member declarations, where only literal/constant values are allowed, not expressions:

   class xyz {                   ⇓
       var $default = get_config("xyz_default");
   

   Put such things in the constructor. See also Why don't PHP attributes allow functions?

   Again note that PHP 7 only allows var $xy = 1 + 2 +3; constant expressions there.

3. JavaScript syntax in PHP

   Using JavaScript or jQuery syntax won't work in PHP for obvious reasons:

   <?php      ⇓
       print $(document).text();
   

   When this happens, it usually indicates an unterminated preceding string; and literal <script> sections leaking into PHP code context.

4. isset(()), empty, key, next, current

   Both isset() and empty() are language built-ins, not functions. They need to access a variable directly. If you inadvertently add a pair of parentheses too much, then you'd create an expression however:

             ⇓
   if (isset(($_GET["id"]))) {
   

   The same applies to any language construct that requires implicit variable name access. These built-ins are part of the language grammar, therefore don't permit decorative extra parentheses.

   User-level functions that require a variable reference -but get an expression result passed- lead to runtime errors instead.

Curly braces { and } enclose code blocks. And syntax errors about them usually indicate some incorrect nesting.

1. Unmatched subexpressions in an if

   Most commonly unbalanced ( and ) are the cause if the parser complains about the opening curly { appearing too early. A simple example:

                                 ⇓
   if (($x == $y) && (2 == true) {
   

   Count your parentheses or use an IDE which helps with that. Also don't write code without any spaces. Readability counts.

2. { and } in expression context

   You can't use curly braces in expressions. If you confuse parentheses and curlys, it won't comply to the language grammar:

              ⇓
   $var = 5 * {7 + $x};
   

   There are a few exceptions for identifier construction, such as local scope variable ${references}.

3. Variable variables or curly var expressions

   This is pretty rare. But you might also get { and } parser complaints for complex variable expressions:

                         ⇓
   print "Hello {$world[2{]} !";
   

   Though there's a higher likelihood for an unexpected } in such contexts.

1. Last statement in a code block

   It can happen for any unterminated expression.

   And if the last line in a function/code block lacks a trailing ; semicolon:

   function whatever() {
       doStuff()
   }            ⇧
   

   Here the parser can't tell if you perhaps still wanted to add + 25; to the function result or something else.

2. Invalid block nesting / Forgotten {

   You'll sometimes see this parser error when a code block was } closed too early, or you forgot an opening { even:

   function doStuff() {
       if (true)    ⇦
           print "yes";
       }
   }   ⇧
   

   In above snippet the if didn't have an opening { curly brace. Thus the closing } one below became redundant. And therefore the next closing }, which was intended for the function, was not associable to the original opening { curly brace.

   Such errors are even harder to find without proper code indentation. Use an IDE and bracket matching.

1. Function declaration parameters

   A rarer occurence for this error is trying to use expressions as default function parameters. This is not supported, even in PHP7:

   function header_fallback($value, $expires = time() + 90000) {
   

   Parameters in a function declaration can only be literal values or constant expressions. Unlike for function invocations, where you can freely use whatever(1+something()*2) etc.

2. Class property defaults

   Same thing for class member declarations, where only literal/constant values are allowed, not expressions:

   class xyz {                   ⇓
       var $default = get_config("xyz_default");
   

   Put such things in the constructor.
     See also Why don't PHP attributes allow functions?

   Again note that PHP 7 only allows var $xy = 1 + 2 +3; constant expressions there.

3. Javascript syntax in PHP

   Utilizing Javascript or jQuery syntax won't work in PHP for obvious reasons:

   <?php      ⇓
       print $(document).text();
   

   When this happens, it usually indicates an unterminated preceding string; and literal <script> sections leaking into PHP code context.

4. isset(()), empty, key, next, current

   Both isset() and empty() are language built-ins, not functions. They need to access a variable directly. If you inadvertently add a pair of parentheses too much, then you'd create an expression however:

             ⇓
   if (isset(($_GET["id"]))) {
   

   Same applies to any language construct that requires implicit variable name access. These built-ins are part of the language grammer, therefore don't permit decorative extra parens.

   User-level functions that require a variable reference -but get an expression result passed- lead to runtime errors instead.

Which doesn't make sense, obviously. Same thing for the usual suspects, for/foreach and while/do etc.

1. Function declaration parameters

   A rarer occurrence for this error is trying to use expressions as default function parameters. This is not supported, even in PHP7:

   function header_fallback($value, $expires = time() + 90000) {
   

   Parameters in a function declaration can only be literal values or constant expressions. Unlike for function invocations, where you can freely use whatever(1+something()*2) etc.

2. Class property defaults

   Same thing for class member declarations, where only literal/constant values are allowed, not expressions:

   class xyz {                   ⇓
       var $default = get_config("xyz_default");
   

   Put such things in the constructor. See also Why don't PHP attributes allow functions?

   Again note that PHP 7 only allows var $xy = 1 + 2 +3; constant expressions there.

3. JavaScript syntax in PHP

   Using JavaScript or jQuery syntax won't work in PHP for obvious reasons:

   <?php      ⇓
       print $(document).text();
   

   When this happens, it usually indicates an unterminated preceding string; and literal <script> sections leaking into PHP code context.

4. isset(()), empty, key, next, current

   Both isset() and empty() are language built-ins, not functions. They need to access a variable directly. If you inadvertently add a pair of parentheses too much, then you'd create an expression however:

             ⇓
   if (isset(($_GET["id"]))) {
   

   The same applies to any language construct that requires implicit variable name access. These built-ins are part of the language grammar, therefore don't permit decorative extra parentheses.

   User-level functions that require a variable reference -but get an expression result passed- lead to runtime errors instead.

Which doesn't make sense, obviously. The same thing for the usual suspects, for/foreach, while/do, etc.

1. Function declaration parameters

   A rarer occurence for this error is trying to use expressions as default function parameters. This is not supported, even in PHP7:

   function header_fallback($value, $expires = time() + 90000) {
   

   Parameters in a function declaration can only be literal values or constant expressions. Unlike for function invocations, where you can freely use whatever(1+something()*2) etc.

2. Class property defaults

   Same thing for class member declarations, where only literal/constant values are allowed, not expressions:

   class xyz {                   ⇓
       var $default = get_config("xyz_default");
   

   Put such things in the constructor.
   See also Why don't PHP attributes allow functions?

   Again note that PHP 7 only allows var $xy = 1 + 2 +3; constant expressions there.

3. Javascript syntax in PHP

   Utilizing Javascript or jQuery syntax won't work in PHP for obvious reasons:

   <?php      ⇓
       print $(document).text();
   

   When this happens, it usually indicates an unterminated preceding string; and literal <script> sections leaking into PHP code context.

4. isset(()), empty, key, next, current

   Both isset() and empty() are language built-ins, not functions. They need to access a variable directly. If you inadvertently add a pair of parentheses too much, then you'd create an expression however:

             ⇓
   if (isset(($_GET["id"]))) {
   

   Same applies to any language construct that requires implicit variable name access. These built-ins are part of the language grammer, therefore don't permit decorative extra parens.

   User-level functions that require a variable reference -but get an expression result passed- lead to runtime errors instead.

1. Absent function parameter

   You cannot have stray commas last in a function call. PHP expects a value there and thusly complains about an early closing ) parenthesis.

                 ⇓
   callfunc(1, 2, );
   

   A trailing comma is only allowed in array() or list() constructs.

2. Unfinished expressions

   If you forget something in an arithmetic expression, then the parser gives up. Because how should it possibly interpret that:

                  ⇓
   $var = 2 * (1 + );
   

   And if you forgot the closing ) even, then you'd get a complaint about the unexpected semicolon instead.

3. Foreach as constant

   For forgotten variable $ prefixes in control statements you will see:

                      ↓    ⇓
   foreach ($array as wrong) {
   

   PHP here sometimes tells you it expected a :: instead. Because a class::$variable could have satisfied the expected $variable expression..

1. Unmatched subexpressions in an if

   Most commonly unbalanced ( and ) are the cause if the parser complains about the opening curly { appearing too early. A simple example:

                                 ⇓
   if (($x == $y) && (2 == true) {
   

   Count your parens or use an IDE which helps with that. Also don't write code without any spaces. Readability counts.

2. { and } in expression context

   You can't use curly braces in expressions. If you confuse parentheses and curlys, it won't comply to the language grammer:

              ⇓
   $var = 5 * {7 + $x};
   

   There are a few exceptions for identifier construction, such as local scope variable ${references}.

3. Variable variables or curly var expressions

   This is pretty rare. But you might also get { and } parser complaints for complex variable expressions:

                         ⇓
   print "Hello {$world[2{]} !";
   

   Though there's a higher likelihood for an unexpected } in such contexts.

1. Parameter lists

   For example misdeclared functions without parameter list are not permitted:

                    ⇓
   function whatever {
   }
   

2. Control statement conditions

   And you can't likewise have an if without condition.

     ⇓
   if {
   }
   

1. Function declaration parameters

   A rarer occurence for this error is trying to use expressions as default function parameters. This is not supported, even in PHP7:

   function header_fallback($value, $expires = time() + 90000) {
   

   Parameters in a function declaration can only be literal values or constant expressions. Unlike for function invocations, where you can freely use whatever(1+something()*2) etc.

2. Class property defaults

   Same thing for class member declarations, where only literal/constant values are allowed, not expressions:

   class xyz {                   ⇓
       var $default = get_config("xyz_default");
   

   Put such things in the constructor.
   See also Why don't PHP attributes allow functions?

   Again note that PHP 7 only allows var $xy = 1 + 2 +3; constant expressions there.

3. Javascript syntax in PHP

   Utilizing Javascript or jQuery syntax won't work in PHP for obvious reasons:

   <?php      ⇓
       print $(document).text();
   

   When this happens, it usually indicates an unterminated preceding string; and literal <script> sections leaking into PHP code context.

4. isset(()), empty, key, next, current

   Both isset() and empty() are language built-ins, not functions. They need to access a variable directly. If you inadvertently add a pair of parentheses too much, then you'd create an expression however:

             ⇓
   if (isset(($_GET["id"]))) {
   

   Same applies to any language construct that requires implicit variable name access. These built-ins are part of the language grammer, therefore don't permit decorative extra parens.

   User-level functions that require a variable reference -but get an expression result passed- lead to runtime errors instead.

1. Absent function parameter

   You cannot have stray commas last in a function call. PHP expects a value there and thusly complains about an early closing ) parenthesis.

                 ⇓
   callfunc(1, 2, );
   

   A trailing comma is only allowed in array() or list() constructs.

2. Unfinished expressions

   If you forget something in an arithmetic expression, then the parser gives up. Because how should it possibly interpret that:

                  ⇓
   $var = 2 * (1 + );
   

   And if you forgot the closing ) even, then you'd get a complaint about the unexpected semicolon instead.

3. Foreach as constant

   For forgotten variable $ prefixes in control statements you will see:

                      ↓    ⇓
   foreach ($array as wrong) {
   

   PHP here sometimes tells you it expected a :: instead. Because a class::$variable could have satisfied the expected $variable expression..

1. Unmatched subexpressions in an if

   Most commonly unbalanced ( and ) are the cause if the parser complains about the opening curly { appearing too early. A simple example:

                                 ⇓
   if (($x == $y) && (2 == true) {
   

   Count your parens or use an IDE which helps with that. Also don't write code without any spaces. Readability counts.

2. { and } in expression context

   You can't use curly braces in expressions. If you confuse parentheses and curlys, it won't comply to the language grammer:

              ⇓
   $var = 5 * {7 + $x};
   

   There are a few exceptions for identifier construction, such as local scope variable ${references}.

3. Variable variables or curly var expressions

   This is pretty rare. But you might also get { and } parser complaints for complex variable expressions:

                         ⇓
   print "Hello {$world[2{]} !";
   

   Though there's a higher likelihood for an unexpected } in such contexts.

1. Parameter lists

   For example misdeclared functions without parameter list are not permitted:

                    ⇓
   function whatever {
   }
   

2. Control statement conditions

   And you can't likewise have an if without condition.

     ⇓
   if {
   }