PHP's migration from a simple scripting language designed to build web pages programatically to a very general server side web language means it serves eight out of ten websites using server-side code.
The new release is based on Zend Engine, which is faster and uses less memory. According to PHP tools vendor Zend Technologies, which led the PHP Next-Gen project on which PHP 7 is based, the performance improvements of PHP 7.0 range between 50% and 200% on real-world apps without changing a line of code. PHP 7 also has consistent 64-bit support.Andi Gutmans, Zend's CEO, says that the new version also has reduced memory requirements, around two-thirds of the original requirements, which means you may get three times the throughput as PHP 5.6.
Syntactically, a null coalescing operator has been added along with a combined comparison operator. Support for return type and scalar type declarations has also been added along with support for anonymous classes.
The new combined comparison operator, <=>, is being referred to as the Spaceship Operator. It can be used for combined comparisons – mostly when dealing with sorting. It is similar to strcmp() or version_compare() in behavior, but it can be used on all generic PHP values with the same semantics as <, <=, ==, >=, >.
The support for return type declarations and scalar type hints means developers will be able to declare what kind of return type a function is expected to have in a similar way to argument Type Hints. Argument type hints and the new return-type declarations also now support new scalar types, so you can denote that you’re expecting strings, floats, ints or bools to be passed or returned.
The changes to the syntax mean some older code is likely to fail under the new version.