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Diffstat (limited to 'Zend/ZEND_CHANGES')
| -rw-r--r-- | Zend/ZEND_CHANGES | 112 |
1 files changed, 0 insertions, 112 deletions
diff --git a/Zend/ZEND_CHANGES b/Zend/ZEND_CHANGES deleted file mode 100644 index 9f5f3441c7..0000000000 --- a/Zend/ZEND_CHANGES +++ /dev/null @@ -1,112 +0,0 @@ -Improvements ------------- - -Zend was designed from the ground up for increased speed, -reduced memory consumption and more reliable execution. We dare -say it meets all of these goals and does so pretty well. Beyond -that, there are several improvements in the language engine -features: - -* References support. $foo = &$a; would make $foo and $a be two - names to the same variable. This works with arrays as well, - on either side; e.g., $foo = &$a[7]; would make $foo and $a[7] - be two names to the same variable. Changing one would change - the other and vice versa. -* Object overloading support. This feature allows various OO - libraries to use the OO notation of PHP to access their - functionality. Right now, no use is made of that feature, - but we'd have a COM module ready by the time PHP 4.0 is released. - A CORBA module would probably follow. -* include() and eval() are now functions, and not statements. - That means they return a value. The default return value from - include() and eval() is 1, so that you can do if (include()) - without further coding. The return value may be changed by - returning a value from the global scope of the included file - or the evaluated string. For example, if 'return 7;' is executed - in the global scope of foo.inc, include("foo.inc") would evaluate - to 7. -* Automatic resource deallocation. Several people have been bitten - by the fact that PHP 3.0 had no concept of reference counting. - Zend adds full reference counting for every value in the system, - including resources. As soon as a resource is no longer referenced - from any variable, it is automatically destroyed to save memory - and resources. The most obvious example for the advantage in this - is a loop that has an SQL query inside it, something like - '$result = sql_query(...);'. In PHP 3.0, every iteration resulted - in another SQL result-set allocated in the memory, and all of the - result sets weren't destroyed until the end of the script's execution. - In Zend, as soon as we overwrite an old result set with a new one, - the old result set which is no longer referenced, is destroyed. -* Full support for nesting arrays and objects within each other, in - as many levels as you want. -* Boolean type. true and false are now constants of type boolean. - Comparing any other value to them would convert that value to a - boolean first, and conduct the comparison later. That means, for - example, that 5==true would evaluate to true (in PHP 3.0, true - was nothing but a constant for the integer value of 1, so 5==true - was identical to 5==1, which was false). -* Runtime binding of function names. This complex name has a simple - explanation - you can now call functions before they're declared! -* Added here-docs support. -* Added foreach. Two syntaxes supported: - foreach(array_expr as $val) statement - foreach(array_expr as $key => $val) statement -* A true unset() implementation. A variable or element that is unset(), is now - sent to oblivion in its entirely, no trace remains from it. -* Output buffering support! Use ob_start() to begin output buffering, ob_end_flush() - to end buffering and send out the buffered contents, ob_end_clean() to end buffering - without sending the buffered contents, and ob_get_contents() to retreive the current - contents of the output buffer. - Header information (header(), content type, cookies) are not buffered. By turning - on output buffering, you can effectively send header information all throughout your - file, regardless of whether you've emitted body output or not. -* Full variable reference within quoted strings: - ${expr} - full indirect reference support for scalar variables - {variable} - full variable support - For example: - $foo[5]["bar"] = "foobar"; - print "{$foo[5]["bar"]}"; // would print "foobar" -* Ability to call member functions of other classes from within member functions or from - the global scope. You can now, for example, override a parent function with a child function, - and call the parent function from it. -* Runtime information for classes (class name, parent, available functions, etc.). -* Much more efficient syntax highlighter - runs much quicker, performs more reliably, and - generates much tighter HTML. -* A full-featured debugger has been integrated with the language (supports breakpoints, - expression evaluation, step-in/over, function call backtrace, and more). - - -Incompatabilities ------------------ - -Zend claims 100% compatability with the engine of PHP 3.0, and is -shamelessly lying about it. Here's why: - -* static variable initializers only accept scalar values - (in PHP 3.0 they accepted any valid expression). The impact - should be somewhere in between void and non existent, since - initializing a static variable with anything but a simple - static value makes no sense at all. - -* The scope of break and continue is local to that of an - include()'d file or an eval()'d string. The impact should - be somewhat smaller of the one above. - -* return statement from a require()'d file no longer works. It - hardly worked in PHP 3.0, so the impact should be fairly small. - If you want this functionality - use include() instead. - -* unset() is no longer a function, but a statement. It was never - documented as a function so the impact should be no bigger than - nada. - -* The following letter combination is not supported within encapsulated - strings: "{$". If you have a string that includes this letter - combination, for example, print "{$somevar"; (which printed the - letter { and the contents of the variable $somevar in PHP 3.0), - it will result in a parse error under Zend. In this case, you - would have to change the code to print "\{$somevar"; - This incompatability is due to the full variable reference - within quoted strings feature added in Zend. - - |