Match expression
Description
Match expressions[fn:rfc] are similar to [Switch expression](Switch expression), but with safer semantics and the ability to return values.
Syntax
// After
this->lexer->lookahead[‘type’]) {
Lexer::T_SELECT => this->UpdateStatement(),
Lexer::T_DELETE => this->syntaxError(‘SELECT, UPDATE or DELETE’),
};
Return value
switch (1) {
case 0:
result = ‘Bar’;
break;
case 2:
$result = ‘Baz’;
break;
}
echo $result;
//> Bar
echo match (1) {
0 => ‘Foo’,
1 => ‘Bar’,
2 => ‘Baz’,
};
//> Bar
No type coercion
switch (‘foo’) {
case 0:
result = “This is what I expected\n”;
break;
}
echo $result;
//> Oh no!
echo match (‘foo’) {
0 => “Oh no!\n”,
‘foo’ => “This is what I expected\n”,
};
//> This is what I expected
No fallthrough
switch ($pressedKey) {
case Key::RETURN_:
save();
// Oops, forgot the break
case Key::DELETE:
delete();
break;
}
match ($pressedKey) {
Key::RETURN_ => save(),
Key::DELETE => delete(),
};
echo match ($x) {
1, 2 => ‘Same for 1 and 2’,
3, 4 => ‘Same for 3 and 4’,
};
Exhaustiveness
switch (operator) {
case BinaryOperator::ADD:
result = rhs;
break;
}
// Forgot to handle BinaryOperator::SUBTRACT
operator) {
BinaryOperator::ADD => rhs,
};
// Throws when $operator is BinaryOperator::SUBTRACT