Key features in PHP 7.4
- Class properties support type declarations.
- Starting from PHP 7.4, arrow functions will provide a shorthand syntax for defining functions with implicit by-value scope binding
- The full variance support is only available if autoloading is used by the user. Also, a single file will now only support non-cyclic type references.
- Numeric literals can contain underscores between digits.
- Weak references in PHP 7.4 will allow the programmers to retain a reference to an object that does not prevent the object from being destroyed.
- Users can now throw exceptions from __toString(). This was previously not permitted in PHP as it used to result in a fatal error.
- The CURLFile now supports stream wrappers in addition to plain file names.
- The FILTER_VALIDATE_FLOAT filter will support the min_range and max_range options, with the same semantics as FILTER_VALIDATE_INT.
- A new FFI extension is introduced. It will provide a simple way to call native functions, access native variables, and create/access data structures defined in C libraries.
- A new IMG_FILTER_SCATTER image filter is added to introduce a scatter filter to images.
