PHP 7 - Scalar Type Declarations

In PHP 7, a new feature, Scalar type declarations, has been introduced. Scalar type declaration has two options −

coercive − coercive is default mode and need not to be specified.

strict − strict mode has to exppcitly hinted.

Following types for function parameters can be enforced using the above modes −

int

float

bool

string

interfaces

array

callable

Example - Coercive Mode

<?php
   // Coercive mode
   function sum(int ...$ints) {
      return array_sum($ints);
   }
   print(sum(2,  3 , 4.1));
?>

9

<?php
   // Strict mode
   declare(strict_types = 1);
   function sum(int ...$ints) {
      return array_sum($ints);
   }
   print(sum(2,  3 , 4.1));
?>

Fatal error: Uncaught TypeError: Argument 2 passed to sum() must be of the type integer, string given, ...