This extension provides operator overloading for PHP 8.
There is an extension for operator overloading in PHP 7, pecl-php-operator, but it has been broken since PHP 7.4. This extension is a rewrite of that extension, but for PHP 8.
These operators are the ones that make the most sense to overload. They are assignment, unary, binary, and comparison operators.
| Operator Name | Operator | Implemented | Function Call |
|---|---|---|---|
| Identity | +$a |
Maybe1 | |
| Negation | -$a |
Maybe1 | |
| Addition | $a + $b |
Yes | $a::__add($b) |
| Subtraction | $a - $b |
Yes | $a::__sub($b) |
| Multiplication | $a * $b |
Yes | $a::__mul($b) |
| Division | $a / $b |
Yes | $a::__div($b) |
| Modulo | $a % $b |
Yes | $a::__mod($b) |
| Exponent | $a ** $b |
Yes | $a::__pow($b) |
| Operator Name | Operator | Implemented | Function Call |
|---|---|---|---|
| Assignment | $a = $b |
Yes | $a::__assign($b) |
| Operator Name | Operator Use | Implemented | Function Call |
|---|---|---|---|
| And | $a & $b |
Yes | $a::__bw_and($b) |
| Or | $a | $b |
Yes | $a::__bw_or($b) |
| Xor | $a ^ $b |
Yes | $a::__bw_xor($b) |
| Not | ~$a |
Yes | $a::__bw_not($b) |
| Shift left | $a << $b |
Yes | $a::__sl($b) |
| Shift right | $a >> $b |
Yes | $a::__sr($b) |
| Operator Name | Operator Use | Implemented | Function Call |
|---|---|---|---|
| Equal | $a == $b |
Yes | $a::__is_equal($b) |
| Identical | $a === $b |
Yes | $a::__is_identical($b) |
| Not equal | $a != $b |
Yes | $a::__is_not_equal($b) |
| Not equal | $a <> $b |
Yes | $a::__is_not_equal($b) |
| Not identical | $a !== $b |
Yes | $a::__is_not_identical($b) |
| Less than | $a < $b |
Yes | $a::__is_smaller($b) |
| Greater than | $a > $b |
Yes2 | $a::__is_greater($b) |
| Less than or equal | $a <= $b |
Yes | $a::__is_smaller_or_equal($b) |
| Greater than or equal | $a >= $b |
Yes2 | $a::__is_greater_or_equal($b) |
| Spaceship | $a <=> $b |
Yes | $a::__spaceship($b) |
| Ternary | $a ?: $b |
No | |
| Null coalescing | $a ?? $b |
No3 |
| Operator Name | Operator Use | Implemented | Function Call |
|---|---|---|---|
| Pre-increment | ++$a |
Yes | $a::__pre_inc |
| Post-increment | $a++ |
Yes | $a::__post_inc |
| Pre-decrement | --$a |
Yes | $a::__pre_dec |
| Post-decrement | $a-- |
Yes | $a::__post_dec |
| Operator Name | Operator Use | Implemented | Function Call |
|---|---|---|---|
| And | $a and $b |
Maybe1 | |
| Or | $a or $b |
Maybe1 | |
| Xor | $a xor $b |
Maybe1 | |
| Not | $a ! $b |
Maybe1 | |
| And | $a && $b |
Maybe1 | |
| Or | $a || $b |
Maybe1 |
| Operator Name | Operator Use | Implemented | Function Call |
|---|---|---|---|
| Concatenation | $a . $b |
Yes | $a::__concat($b) |
There are a few assignment operators that are overloaded. These are an operator
and an assignment operator combined4. For example, += is an addition assignment
operator.
| Operator Name | Operator Use | Implemented | Function Call |
|---|---|---|---|
| Addition Assignment | $a += $b |
Yes | $a::__assign_add($b) |
| Subtraction Assignment | $a -= $b |
Yes | $a::__assign_sub($b) |
| Multiplication Assignment | $a *= $b |
Yes | $a::__assign_mul($b) |
| Division Assignment | $a /= $b |
Yes | $a::__assign_div($b) |
| Modulo Assignment | $a %= $b |
Yes | $a::__assign_mod($b) |
| Exponent Assignment | $a **= $b |
Yes | $a::__assign_pow($b) |
| And Assignment | $a &= $b |
Yes | $a::__assign_and($b) |
| Or Assignment | $a |= $b |
Yes | $a::__assign_or($b) |
| Xor Assignment | $a ^= $b |
Yes | $a::__assign_xor($b) |
| Shift left Assignment | $a <<= $b |
Yes | $a::__assign_sl($b) |
| Shift right Assignment | $a >>= $b |
Yes | $a::__assign_sr($b) |
| Coalesce Assignment | $a ??= $b |
No | |
| Concat Assignment | $a .= $b |
Yes | $a::__assign_concat($b) |
There are a number of opcodes, more than 200 in total. Many of them don't make
sense to overload. The full opcode list can be found in the php-src repo
here.
Footnotes
-
This might be the same as other opcodes, or maybe there is no opcode for it, but I'm not sure. I haven't tested it yet. ↩ ↩2 ↩3 ↩4 ↩5 ↩6 ↩7 ↩8
-
Internally in the PHP engine, the
>and>=operators are just the<and<=operators with the arguments swapped. This extension swaps the operands back to the correct order before calling the function. This might cause some issues comparing objects to objects when not overloading the operator. Further testing is required. ↩ ↩2 -
I've tried to implement this one, but no matter what I return the PHP engine doesn't want to take the left hand argument. This might be kinda moot to do though, since if an object is null-ish, it wouldn't be able to check if it's null, right? (The object wouldn't be initialized, is what I'm getting at.) I'm not sure what to have the function return to satisfy the PHP engine, and if I can't write the PHP correctly, then that also means that I'd need to write up a special documentation note just for that function to describe how to implement it and what to return to get it to work in the userland (since I can't get it to work in userland myself). ↩
-
There isn't a separate opcode for
+=, it's justZEND_ADDas theextra-detailswithin theZEND_ASSIGN_OPopcode. Those separate opcodes were removed in PHP 7.4. This is one of the things that broke the original operator overloading extension. ↩
